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Effects of High Tunnel Production on Florida Strawberry Growth, Yield and Postharvest Quality

Permanent Link: http://ufdc.ufl.edu/UFE0025065/00001

Material Information

Title: Effects of High Tunnel Production on Florida Strawberry Growth, Yield and Postharvest Quality
Physical Description: 1 online resource (125 p.)
Language: english
Creator: Salame, Teresa
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: cutivars, florida, strawberry
Horticultural Science -- Dissertations, Academic -- UF
Genre: Horticultural Science thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The United States is the largest producer of strawberries in the world, with most of them targeted towards the fresh market. Protected strawberry production is widely used in Europe and other parts of the world; however, in California and Florida open-field production remains as the main production system. Strawberry production in high tunnels could potentially increase yield, improve fruit quality, promote early ripening, and reduce rain damage. If adopted in Florida, this technology opens new possibilities for strawberry production practices and eventually increases grower profits by improving winter production and providing fruit early in the season, allowing the advantage of high market prices during winter and early spring. The objectives of the study were to compare the effects of high tunnel and open-field production on growth, fruit earliness and yield of strawberry cultivars and to evaluate postharvest quality of strawberries. Six treatments were tested using three strawberry cultivars and two production systems. The experimental design was a split-plot design with four and six replications with production systems in the main plots and cultivars in the subplots. Passively-ventilated tunnels were utilized for the study. Strawberry plant diameter and chlorophyll content were determined at 8 and 12 weeks after transplanting and marketable fruit through thirty harvests per season. Fruits per plot were collected to determine color, soluble solids content and marketability of each treatment at harvest and after 8 days of storage at 7.2oC. During 2007-08 season, vitamin C content, acidity, pH and fruit firmness were also measured. Strawberry plants grown inside the high tunnel were 18% and 19% than plants in the open field at 8 weeks and 12 weeks after transplant for 2007-08 season. Early yields were 59% and 16% and total yields were 64% and 50% higher inside the high tunnels compared with open field for 2007-08 and 2008-09 seasons, respectively. Production systems had significant effects on marketable fruit percentage and soluble solids for ?Winter Dawn? and ?Florida Elyana?, with higher marketability and higher soluble solids from inside the high tunnels. For ?Strawberry Festival? the production systems had no effects on fruit marketability after storage in both seasons.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Teresa Salame.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Santos, Bielinski M.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0025065:00001

Permanent Link: http://ufdc.ufl.edu/UFE0025065/00001

Material Information

Title: Effects of High Tunnel Production on Florida Strawberry Growth, Yield and Postharvest Quality
Physical Description: 1 online resource (125 p.)
Language: english
Creator: Salame, Teresa
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 2009

Subjects

Subjects / Keywords: cutivars, florida, strawberry
Horticultural Science -- Dissertations, Academic -- UF
Genre: Horticultural Science thesis, M.S.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract: The United States is the largest producer of strawberries in the world, with most of them targeted towards the fresh market. Protected strawberry production is widely used in Europe and other parts of the world; however, in California and Florida open-field production remains as the main production system. Strawberry production in high tunnels could potentially increase yield, improve fruit quality, promote early ripening, and reduce rain damage. If adopted in Florida, this technology opens new possibilities for strawberry production practices and eventually increases grower profits by improving winter production and providing fruit early in the season, allowing the advantage of high market prices during winter and early spring. The objectives of the study were to compare the effects of high tunnel and open-field production on growth, fruit earliness and yield of strawberry cultivars and to evaluate postharvest quality of strawberries. Six treatments were tested using three strawberry cultivars and two production systems. The experimental design was a split-plot design with four and six replications with production systems in the main plots and cultivars in the subplots. Passively-ventilated tunnels were utilized for the study. Strawberry plant diameter and chlorophyll content were determined at 8 and 12 weeks after transplanting and marketable fruit through thirty harvests per season. Fruits per plot were collected to determine color, soluble solids content and marketability of each treatment at harvest and after 8 days of storage at 7.2oC. During 2007-08 season, vitamin C content, acidity, pH and fruit firmness were also measured. Strawberry plants grown inside the high tunnel were 18% and 19% than plants in the open field at 8 weeks and 12 weeks after transplant for 2007-08 season. Early yields were 59% and 16% and total yields were 64% and 50% higher inside the high tunnels compared with open field for 2007-08 and 2008-09 seasons, respectively. Production systems had significant effects on marketable fruit percentage and soluble solids for ?Winter Dawn? and ?Florida Elyana?, with higher marketability and higher soluble solids from inside the high tunnels. For ?Strawberry Festival? the production systems had no effects on fruit marketability after storage in both seasons.
General Note: In the series University of Florida Digital Collections.
General Note: Includes vita.
Bibliography: Includes bibliographical references.
Source of Description: Description based on online resource; title from PDF title page.
Source of Description: This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility: by Teresa Salame.
Thesis: Thesis (M.S.)--University of Florida, 2009.
Local: Adviser: Santos, Bielinski M.

Record Information

Source Institution: UFRGP
Rights Management: Applicable rights reserved.
Classification: lcc - LD1780 2009
System ID: UFE0025065:00001


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1 EFFECTS OF HIGH TUNNEL PRODUCTION ON FLORIDA STRAWBERRY GROWTH, YIELD AND POSTHARVEST QUALITY By TERESA PAOLA SALAME DONOSO A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF T HE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2009

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2 2009 Teresa Paola Salam Donoso

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3 To Gloria Isabel and Nuncio Fuad

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4 ACKNOWLEDGMENTS I would like to thank my family and f riends, whose constant encouragement and love have always inspired me. In addition, this work would not have been possible without the support and orientation of my advisor Dr. Bielinski Santos and the members of my supervisory committee Dr. Craig Chandl er and Dr. Steven Sargent to whom I am greatly thankful.

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5 TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................ ................................ ................................ ............... 4 LIST OF TABLES ................................ ................................ ................................ ........................... 7 LIST OF FIGURES ................................ ................................ ................................ ......................... 8 ABSTRACT ................................ ................................ ................................ ................................ ... 12 CHAPTER 1 INTRODUCTION ................................ ................................ ................................ .................. 14 2 LITERATURE REVIEW ................................ ................................ ................................ ....... 18 Strawberry Description ................................ ................................ ................................ ........... 18 Cultivar Description ................................ ................................ ................................ ................ 19 Strawberry Production Systems ................................ ................................ .............................. 21 High Tunnel Effects on Environmental Conditions ................................ ............................... 22 Postharvest Qual ity ................................ ................................ ................................ ................. 24 Importance of the Study ................................ ................................ ................................ .......... 27 3 EFFECTS OF HIGH TUNNEL PRODUCTION ON FLORIDA STRAWBERRY GROWTH, YIELD AND POSTHARVEST QUALIT Y. ................................ ...................... 28 Materials and Methods ................................ ................................ ................................ ........... 28 Results and Discussion ................................ ................................ ................................ ........... 32 2007 08 Season ................................ ................................ ................................ ............... 32 Plant diameter and chlorophyll content ................................ ................................ .... 32 Yields ................................ ................................ ................................ ....................... 33 C olor ................................ ................................ ................................ ......................... 33 Fruit firmness ................................ ................................ ................................ ........... 36 Marketable fruit ................................ ................................ ................................ ........ 36 Soluble solids ................................ ................................ ................................ ........... 37 Titratable acidity and pH ................................ ................................ .......................... 39 Vitamin C ................................ ................................ ................................ ................. 40 2008 09 Season ................................ ................................ ................................ ............... 43 Plant diameter and chlorophyll content ................................ ................................ .... 44 Yields ................................ ................................ ................................ ....................... 44 Color ................................ ................................ ................................ ......................... 45 Marketable fruit ................................ ................................ ................................ ........ 49 Soluble solids ................................ ................................ ................................ ........... 50 4 SUMMARY AND CONCLUSIONS ................................ ................................ ................... 101

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6 APPENDIX A TEMPERATURE DATA FRO M FAWN WEATHER REPOR T FOR BALM, FLORIDA DURING 2007 08 AND 2008 09 SEASONS ................................ ................... 106 B EFFECTS OF PRODUCTI ON SYSTEM ON STRAWBE RRY PH ON STRAWBERRY FRUITS BE FORE AND AFTER 8 DAY S STORAGE AT 7.2 O C IN FIVE DIFFERENT STORA GE TESTS ON 2007 08 SEASON ................................ ......... 116 LIST OF REFERENCES ................................ ................................ ................................ ............. 120 BIOGRAPHICAL SKETCH ................................ ................................ ................................ ....... 125

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7 LIST OF TABLES Table page 3 1 Data from temperature sensors located in open field and hi gh tunnel at 10 cm height, and temperature from FAWN weather report, for Balm during 2007 08 season. ............. 53 3 2 Effects of production systems and strawberry cultivars on chlorophyll content and pl ant canopy diameter at 8 and 12 weeks after transplanting (WAT). 2007 08 Season. ................................ ................................ ................................ ............................... 54 3 3 Effects of production systems and strawberry cultivars on early yield and total yield. 2007 08 Season. ................................ ................................ ................................ ................. 55 3 4 Effects of production systems and strawberry cultivars on yield 6 harvests following a freeze or near freeze temperature event. 2007 08 Season. ................................ .............. 56 3 5 Data from temperature sensors located in open field and high tunnel at 10 cm height, and temperature from FAWN weather report, for Balm during 2008 09 season. ............. 57 3 6 Effects of production systems and strawberry cultivars on chlorophyll content and plant canopy diameter at 8 and 12 weeks after transplanting (WAT). 2008 09 Season. ................................ ................................ ................................ ............................... 58 3 7 Effects of produ ction systems and strawberry cultivars on early yield and total yield. 2008 09 Season. ................................ ................................ ................................ ................. 59 3 8 Effects of production systems and strawberry cultivars on yield 6 harvests following a freeze or n ear freeze temperature event. 2008 09 Season. ................................ .............. 60 A 1 Daily average of data from FAWN weather report taken at 60 cm from soil, for Balm during 2007 08 season. ................................ ................................ ................................ .... 107 A 2 Daily average of data from FAWN weather report taken at 60 cm from soil, for Balm during 2008 09 season. ................................ ................................ ................................ .... 111

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8 LIST OF FIGURES Figure page 3 1 Overview of strawberry field production in open field (left) and in high tunnel (right) on a freeze event. January 3, 2008, temperature dropped to 2.8 o C. ................................ 61 3 2 tests. 2007 08 Season. ................................ ................................ ................................ ........ 62 3 3 strawberry before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 63 3 4 strawberry before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 64 3 5 tests. 2007 08 Season. ................................ ................................ ................................ ........ 65 3 6 strawberry before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 66 3 7 E strawberry before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 67 3 8 Effe tests. 2007 08 Season. ................................ ................................ ................................ ........ 68 3 9 strawberry before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 69 3 10 E strawberry before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 70 3 11 strawberry before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 71

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9 3 12 Effect before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ............................... 72 3 13 Effects of productio before and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ............................... 73 3 14 Effects of production system on after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. ................... 74 3 15 Effects of production system on marketable fruit on 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ........................... 75 3 16 after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. ........................... 76 3 17 fore and after 8 days storage at 7.2 o C in five different storage tests. 2007 08. Season. ................................ ................................ ................................ ....... 77 3 18 strawberry b efore and after 8 days storage at 7.2oC in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 78 3 19 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 79 3 20 strawberry before and aft er 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 80 3 21 before and after 8 days stora ge at 7.2 o C in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ............................... 81 3 22 before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ............................... 82 3 23 o C in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ........ 83 3 24 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ................. 84

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10 3 26 2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ........ 86 3 27 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ................. 87 3 28 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ................. 88 3 29 7.2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ........ 89 3 30 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ................. 90 3 31 strawberry before and after 8 days storage at 7.2 o C i n five different storage tests. 2008 09 Season. ................................ ................................ ................................ ................. 91 3 32 .2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ........ 92 3 33 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ................. 93 3 34 strawberry before and after 8 days storage at 7. 2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ................. 94 3 35 storage at 7.2 o C in five different storage tes ts. 2008 09 Season. ................................ ....... 95 3 36 storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ....... 96 3 37 storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ....... 97 3 38 content before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ .......................... 98

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11 3 39 before and after 8 days storage at 7.2 o C in four different storage tests. 2008 09 Season. ................................ ................................ ................................ ............................... 99 3 40 Effec before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season. ................................ ................................ ................................ ............................. 100 B 1 Effects of prod before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. ................................ ................................ ................................ ............................. 117 B 2 Effects of production syste and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. .......... 118 B 3 Effects of production system on strawberry pH o and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season. .......... 119

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12 Abstract of Thesis Presented to the Graduate School of the University of Florida i n Partial Fulfillment of the Requirements for the Degree of Master of Science EFFECTS OF HIGH TUNNEL PRODUCTION ON FLORIDA STRAWBERRY GROWTH, YIELD AND POSTHARVEST QUALITY By Teresa Paola Salam Donoso August 2009 Chair: Bielinski M. Santos Major: Hort icultural Sc ien ce The United States is the largest producer of strawberries in the world, with most of them targeted towards the fresh market. Protected strawberry production is widely used in Europe and other parts of the world; however, in California an d Florida open field production remains as the main production system. Strawberry production in high tunnels could potentially increase yield, improve fruit quality, promote early ripening, and reduce rain damage. If adopted in Florida, this technology ope ns new possibilities for strawbe rry production practices and eventual ly increases grower profits by improving winter production and providing fruit early in the season, allowing the advantage of high market prices during winter and early spring. The objec tives of the study w ere to compare the effects of high tunnel and open field production on growth, fruit earliness and yield of strawberry cultivars and to evaluate postharvest quality of strawberries Six t reatments were tested using three stra wberry cult ivars and two production systems. The experimental design was a split plot design with four and six replications with production systems in the main plots and cultivars in the subplots. Passively ventilated tunnels were utilized for the study. Strawberry p lant diameter and chlorophyll content were determined at 8 and 12 weeks after transplanting and marketable fruit through thirty harvests per season. Fruit s per plot were collected to determine color, soluble solids content and

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13 marketability of each trea tme nt at harvest and after 8 days of storage at 7.2 o C. During 2007 08 season, vitamin C content, acidity, pH and fruit firmness were also measured. Strawberry plants grown inside the high tunnel were 18% and 19% than plants in the open field at 8 weeks and 12 weeks after transplant for 2007 08 season Early yield s were 59% and 16% and total yields were 64% and 50% higher inside the high tunnels compared with open field for 2007 08 and 2008 09 seasons respectively Production systems had significant effects on m arketable fruit percentage and soluble solids higher marketability and higher soluble solids from inside the high tunnels F had no effects on fruit marketability after storage in both seasons

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14 C HAPTER 1 INTRODUCTION The commercially grown strawberry ( Fragaria x annanasa Duch.) is a natural hybrid between two American species: F. chiloensis and F. virginiana (NASGA, 1982). It is a perennial woody plant composed of a compressed stem or stems (crowns) from which leaves, runners, roots, and inflorescences emerge. The structure typically thought of as the fruit is an aggregate of single seeded fruits know as achenes, which are located on the outside of a red fleshy receptacle (Darnell, 2003). This fruit crop is widely spread around the world and it can be found in countries from the Ar c tic to the tropics (Childers, 1980). The United States is the largest grower of strawberry in the world with an area of 22,300 hecta res, followed by Russia and Spain (FAO, 2008). California grows 60% of the strawberry production in the United States (11,330 hectares), followed by Florida with 15% of the planted area (2,850 hectares). The fresh market is the main destination for about 7 of strawberry production in Florida occurs in the west central part of the state, specifically in Hillsborough County (Santos et al 2007). Hillsborough County has mostly fine, deep sandy soils and production occurs during the dry winter months, when temperatures average 17 o C, with maximum and minimum temperatures of 31 and 2 o C, respectively (FAWN, 2009). There are two main production syst ems for strawberry: open field and protective culture. Protective structures include greenhouses, high tunnels, and mini tunnels. A greenhouse is a structure with a glass or plastic roof and walls; air warmed mainly by heat from the soil is retained in the building. This characteristic can be beneficial for winter season production and for crop s that need high temperatures. On the other hand, during summer the temperature is too hot for many crop plants. Crops inside greenhouse s are produced in growing medi a. Structures

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15 range in size from small sheds to very large buildings. Greenhouses can be high technology production, with automatic equipment such as screens, lights, and heating and cooling systems controlled by computers (Ross, 1994). High tunnels are un heated, plastic covered, solar greenhouses, with passive ventilation through roll up si de walls (Orzolek et al., 2004); height might vary from 2 m to more than 5 m (Blomgren and Frisch, 2007). The crop is grown usually on soil. However, pot, bag and sack c ulture can be used, along with various growing media (e.g. peat, perlite, pine bark) depending on availability, price and crop. Mini tunnels or low tunnels are made of galvanized iron bars, with a height of about 50 cm fo r strawberry. Plants are grown i n t he soil. Mini tunnels are covered with clear plastic during cold weather or rain events (Soria Navarro, 2008b). Open field production is the main system used in the United States and Australia, while in Europe and Latin America high tunnels, mini tunnels a nd greenhouses systems are widely used (Santos et al., 2008). In Florida and California strawberry transplants are planted in raised beds, and covered with plastic mulch. The crop is drip irrigated, and safeguarded from frost by us ing row covers or sprin kler irrigation. However, strawberry production under protected structures might not need the use of sprinkler irrigation for freeze protection. Among the potential benefits of growing strawberries in high tunnels are yield improvement, fruit quality enhan cement, reduction of the incidence of insect populations, decreasing weed interference, and protection from rain damage (Chism, 2002; Jett, 2007; Kadir et al 2006; Ozdemir and Kaska, 1997; Voca et al 2007). In addition, high tunnels could diminish the effect of cold weather on late fall and winter production. The high tunnel effects on the crop may be due to changes in photosynthetic active radiation (PAR), temperature, air movement, and relative humidity. Photosynthetic organisms use light in a spectra l range between 400 and 700 nm, which may influence plant growth.

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16 Temperature affect s evapotranspiration, respiration and water absorption. Air movement might affect photosynthesis by affecting air composition, and improve fruit qual ity by reducing wind ve locity. I n cucumber, an increase in relative humidity affected leaf elongation, producing larger leaves (Bakker, 1991). Fresh s trawberry is considered one of most perishable fruit crops for this reason its postharvest quality is an important issue. Qualit ee of excellence or superiority; is a combination of attributes, properties or characteristic s that give each commodity appearance, firmness an d shelf life are important attributes O n the other hand consumer s judge quality by fruit appearance including size, shape, color, gloss iness and absence of disease and decay. Q uality of strawberry fruit is usually describe d based o n flavor which includes sweetness, acidity, astringen cy, bitterness, and aroma. T exture is also related to flavor including firmness, crispness and juiciness. Nutritive characteristic including soluble solids content, acidity, vitamin C and anti oxidants compounds are also consid ered in this matter (Cordenunsi et al., 2003; Kader, 2000; Sturm et al., 2003). For the purpose of this study, from the wide variety of characteristics mention ed above sweetness, acidity, color, vitamin C, appearance and firmness were selected to be analyz ed before and after s torage In spite of the popular use of high tunnels and protected agriculture in countries such as China, Spain, and Japan among others (Lamont, 2009), it is still necessary to investigate their effects on Florida strawberry productio n, due to the differences in climate, cultivars and production systems T herefore, t he objective of this research was to understand the effects of high tunnels on strawberry production, in comparison with open field production. The null hypotheses of this research were:

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17 a) There is no effect due to production system on plant growth, yield, fruit quality or postharvest shelf life. b) There is no effect due to cultivar on plant growth, yield, fruit quality or postharvest shelf life. c) There is no effect due to the i nteraction between production system and cultivar on plant growth, yield, fruit quality or postharvest shelf life.

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18 C HAPTER 2 LITERATURE REVIEW Strawberry Description The strawberry is a small plant that belongs to the Rosaceae family and the Fragaria gen us. The basic chromosome number for this genus is x=7, there about twenty species of Fragaria that can be classified in four groups based on ploidy levels diploid (2n=14), tetraploid (2n=28), hexaploid (2n=42) and octoploid (2n=56). The strawberry commerci ally grown ( F. x ananassa Duch) correspond to the octoploid group (Lopez Aranda, 2008). The Romans are thought to be the first ones who cultivated strawberries. The wild Fragaria species are distributed mainly in three zones: the Americas, Europe, and Asia (Davis, 2008). However, the cultivated strawberry is a widely adapted crop, able to grow in diverse areas. The Food and Agricultural Organization of the United Nation s listed 71 countries where strawberries were grown in 2007. The world leaders in strawbe rry production, based on percentage of the total fruit produced, it is the U nited S tates (29%), the Russian Federation (8.5%) and Spain (7%) (FAO, 2008). Strawberry is a perennial plant which is frequently cultivated as an annual (Galleta and Bringhurst, 1 990). Its leaves are trifoliate and are placed helicoidally around the crown (Darrow, 1966), and they usually remain on the plant for one to three months. The root system is formed by 20 to 30 primary roots and hundreds of lateral roots. The roots are main ly superficial with about 90% of them in the first 15 cm of soil (Dana, 1980). Environmental conditions may stimulate the development of leaf axillary buds or branch crowns. These axillary crowns do not have their own roots, and remain attached to the main crown. Runners or stolons are horizontal stems with two nodes, originated from the axillary buds of the crown (Darnell, 2003; Galletta

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19 and Bringhurst, 1990). Strawberry plants propagate by developing runners that produce daughter plants which root into th e soil at various distances from the parent plant. The strawberry inflorescence is a modified stem terminated by a primary flower. Branches emerge at nodes from buds. Each branch is terminated by a flower. Following the primary flower, there are typically two secondary, four tertiary and eight quaternary flowers, and their distribution may vary between cultivars and locations. Flowers generally have five petals and ten green sepals; stamen numbers range from 20 to 35, and pistils from 60 to 600. Primary f lowers have more pistils than secondary flowers (Handley, 2003). The true strawberry fruits are the achenes. Each pistil develops into an achene if the one ovary it contains is fertilized. The receptacle is modified stem tissue on to which the achenes are arranged, and is also the edible part of the fruit (Darnell, 2003). Strawberry cultivars are classified based on how they respond to photoperiod exposure in three categories : S hort day or June bearing cultivars initiate flower buds during short days (i.e. classified as short day types: L ong day or ever bearing cultivars initiate flower buds under long days or days with more than 97). And finally, day neutral cultivars are insensitive to light with regards to flower initiation and will initiate flowers Chandler and Legard, 2003). Cultivar Desc ription 'Strawberry Festival' was released by the University of Florida in 2000. This cultivar originated from a 1995 cross between 'Rosa Linda' a high early season yielder with desirable fruit shape, and 'Oso Grande', a University of California cultivar characterized by its ability to produce large, firm fruit (Crocker and Chandler, 2000). 'Strawberry Festival' has a vigorous plant

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20 that tends to produce numerous runners if planted in early October in central Florida. The calyx is large and showy. Its fr uit is attached to long pedicels, is medium to large, and mostly conic in shape. The external color of fully mature fruit is deep red and glossy, while internal color is bright red. The fruit has also very firm texture and excellent flavor. 'Strawberry F estival' is susceptible to anthracnose fruit rot (caused by Colletotrichum acutatum ), Colletotrichum crown rot (caused by C. gloeosporodies ), and angular leaf spot (caused by X. fragariae) (Crocker and Chandler, 2000; Chandler and Legard, 2003). During the 2006 07 season produced 48 t/ha in a central Florida trial (Santos et al 2007). s FL 93 10 3, and the pollen parent was FL 95 316, both non paten ted University of Florida breeding selections (Chandler, C.K., 200 9. Patent number US 2009/0013438 ). It has high early season (November through February) production when planted the last week of September or the first week of October in Florida. It produce s medium to large fruit on small plants, and its fruits are moderately resistant to Botrytis and Anthracnose fruit rot diseases when grown in west central Florida or other areas with a similar, subtropical climate (FFSP, 2008). During the 2006 07 2007). in 2008. Originated from FL 96 FL 95 200 (resulted from the cross of the lines FL 93 46 and FL 93 66, both with pedigree 2009). It produces fruit from December through March in Florida and these fruit a re large, firm, and flavorful. moderately resistant to Botrytis fruit rot, and Anthracnose fruit rot (Callies, 2008). Nonetheless, because its fruit are quite susceptible to rain damage, which causes surface cracking, it is only

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21 recommended for protected culture (Ch season (Callies, 2008). During the 2006 and a total yie ld of 47 t/ha in a central Florida trial (Santos et al, 2007). Strawberry Production Systems There are two main production systems for strawberry: open field and under protective structures such as greenhouses, high tunnels and mini tunnels. I pen field production system, strawberries are p lanted in pre formed beds, 61 to 71 cm wide and about 20 cm high. Soil is fumigated usually with a mixture of methyl bromide and chloropicrin. Beds are covered with black polyethylene mulch after injection of the fumigant. A small amount up to 50 kg/ha of preplant fertilizer is sometimes used, and is applied broadcast to the soil just before beds are formed. Fertilization and pest control is do ne according to IFAS (Institute of Food and Agricultural Sciences) r ecommendations (Peres et al., 2006). Fertigation is applied through a single drip tape (0.056 L/m/min), and a 15 L/min sprinkler system is used for frost protection and crop establishment. In most cases, bare root transplants are planted in double rows. Af ter transplanting, overhead irrigation is used for 8 hours for the first 10 days to ensure plant establishment. The high tunnel production system is in most aspects very similar to the open field system Both systems use the same type of beds, soil fumigat ion, preplant fertilizer, fertigation and pest control, bare root transplants, and overhead irrigation for plant establishment. The main difference between the systems is that with the high tunnel system beds are located inside the passively ventilated str ucture which is equipped with roll up side walls managed manually. High tunnels are usually 5 to 10 m wide and 2 m to 5 m tall. The design can be customized to the needs of growers and the available equipment. High tunnels can be built as a single tunnel o r as a multi units (Soria Navarro, 2008b).

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22 In Florida, the side walls are kept open for most of the season; however, when a freeze is expected the side walls are lowered the day before to help retain heat and maintain the air temperature above 0C. In thi s system, sprinklers are used only for crop establishment. In southern California the main production system is open field. The beds are 152 to 172 cm wide and 36 cm high. Four row beds with 36 cm within row plant spacing is common, which gives a plant de nsity of 76,850 plants per hectare. Plastic mulch is used and two drip lines per bed are installed under the mulch, preplant fertilized is applied broadcast, and liquid fertilizer trough the drip. Sprinkler irrigation is used for crop establishment. Pestic ide applications are based on recommendations from U niversity of C alifornia C ooperative Extension Service. Strawberry harvest is from January to mid July (Klonsky and De Moura, 2001). In Spain all the strawberries areas are produced using protected cultur e (i.e., mini tunnels, high tunnels or greenhouses). Strawberry plant s are grown in 30 to 35 cm high raised beds with a top width of 45 to 55 cm and a bottom width of 55 to 65 cm, and covered with plastic mulch. Additional specifications include one drip t ape per bed, two rows of plants per bed with a distance between ro ws of 22 to 28 cm, and a within row plant spacing of 25 to 35 cm, depending on the vigor of the cultivar. Plant populations range from 50,000 to 70,000 plants /ha In addition, in some places strawberries are being grown in soilless systems, with a plant density of 100,000 plants per hectare (Soria Navarro, 2008a). High Tunnel Effects on Environmental Conditions Tunnels are considered non permanent structures because they do not use electricit y, heaters or automatic ventilation systems (Panter, 2009). High tunnels can extend the season in cold climates and protect from rain, wind, hail and the occasional freeze in warm area s (Panter, 2009). Temperature differences inside and outside high tunne ls can vary between 2 and 17 o C (Kadir et al., 2006). Temperatures inside high tunnels are higher during the day, but similar to

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23 the open field during the night (Montero et al., 1985). Nevertheless, the polyethylene plastic cover of the tunnels reduces the photosynthetic active radi ation (PAR) by 40% (Santos et a l 2008). In locations with low PAR there could be insufficient light to reach the minimum required for the plant to develop normally, which might result in lower yields. However, that is not the c ase in Florida. High tunnels protect the crop from rain, which can result in lower air humidity and soil moisture (Montri and Biernbaum, 2009). Accordingly, high tunnels may also help reduce nutrient leaching (HTVSFPT, 2003). On the other hand, if there is not enough ventilation or if the sides and ends of the high tunnel are closed, temperature and humidity inside the tunnel can increase significantly (Montri and Biernbaum, 2009) The use of high tunnels can enhance the incidence of powdery mildew ( caused by Sphaerotheca macularis ) and two spotted spider mites ( caused by Tetranychus urticae ) (Demchak, 2004; Pottorff and Panter, 2009). High tunnels might also provide an opportunity to grow crops or cultivars that are sensitive to rain, Strawberry yields in high tunnels can be as much as 25% greater than those in the open field (Demchak, 2004). High tunnels have the potential to extend the early fall and late spring seasons. This can provide an opportunit y to produce ripe fruit when overall fruit production is low and prices are high (HTVSFPT, 2003; Kadir et al., 2006). Fruit produced under high tunnels might have better quality because of protection from rain and wind, which might increase its shelf life (HTVSFPT, 2003; Jett, 2007). Acidity, soluble solids content and vitamin C have been reported to be higher in strawberries from high tunnels compared to those from the open field (Kadir et al., 2006; Voca et al., 2007). High tunnels are used for a variety of crops. Plants destined for the cut flower industry growing inside high tunnels produce more stems per week than similar plants growing outside

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24 (Wien, 2009) It has been reported that protection from low temperatures allows tunnel grown plants to start producing up to a month earlier and continue several weeks longer than normal, while the protection from rain helped to main tain flower quality In California, high tunnels allow raspberries ( Rubus idaeus) to be produced out of season (Gaskell, 2004). Cher ries ( Prunus avium ) grown in Michigan under high tunnels produced fruit earlier, with larger size, highe r sugar levels and less wind bruising than fruits harvested outside of the high tunnel (Lang, 2009). Moreover, tomato ( Solanum lycopersicum ) harvest in high tunnels in Pennsylvania can begin earlier and last longer than in the open field, increasing the wholesale prices (Orzolek et al., 2002). Also, romaine lettuce ( Lactuca sativa ) grown in high tunnels was cleaner when compared to open field grown lettuc e, which requires intense washing (Rader and Karlsson, 2006). Postharvest Quality Strawberry is a non climacteric fruit and must be harvested at full maturity to achieve the maximum quality in relation to color and flavor (Voca et al., 2007) The fruit rip eness at harvest time will influence the quality for the final market. Matu re fruit seem to be more susceptible to mechanical damage than immature fruit and overripe fruit are likely to become soft after harvest (Kader, 1996 ). The US No. 1 standard for f r esh consists of strawberries of one variety or similar varietal characteristics with the calyx attached, firm, not overripe or undeveloped, and free from mold or decay and free from damage caused by dirt, moisture, foreign matter, disease, insects, or mech anical or other means (USDA, 1965). Each fruit has not less than three fourths of its surface showing a pink or red color, with a minimum diameter of not less than 1.9 cm The US standard description of fruit quality specifies the appearance that strawberr y fruit should have to be marketable, but does not precise the organoleptic characteristics or nutritional value, which usually are the characteristics that the consumer seek. The term quality is a broad term which usually referred to various product attri butes including appearance sensory attributes such as

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25 color, taste, smell and crispness and the nutritive characteristics such as sugar/acid ratio, quantity of soluble solids, vitamin C, total acids and anti oxidative compounds ( Cordenunsi et al., 2003; S turm et al., 2003). For the purpose of this study, from the wide variety of characteristics mention ed above sweetness, acidity, color, vitamin C, appearance and firmness were selected to be analyzed before and after storage for all the treatments. Level s of total titratable acidity and sweetness are important components of strawberry flavor. At the beginning of the ripening process the sugar/acid ratio is low, which makes the fruit taste sour but d uring the ripening process the fruit acids are degraded, the sugar content increases and the sugar/acid ratio achieves a higher value. Overripe fruits have very low levels of fruit acid and therefore lack the characteristic strawberry flavor (OECD, 2005). Sweetness can be estimated through the soluble solids co ntent This value is obtained using a refractometer and th e results are reported in o Brix and express the soluble solids content in the sample. Citric acid is the most abundant organic acid in strawberries, therefore total titratable acidity is measured a s citric acid content. Color can be measure d using a hand held colorimeter and is expressed as lightness (L*) hue angle, and chroma (C*). H ue is an angle in a color wheel of 360 o with 0 representing the hues red purple, 90 o yellow, 180 o bluish green and 270 o blue. C hroma (C*) represent s the intensity of the hue angle (Nunes et al., 2002) Lightness values describe darkening during storage, which could occur from increase in pigment concentration or oxidative browning reactions. Lightness, hue angle and ch roma values together give an objective determination of color, and allow analyzing and comparing different colors without the errors of subjective color determination (McGuire, 1992).

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26 Vitamin C is t he most important vitamin in fruits and vegetables for hu man nutrition an d more than 90% of it is supplied by fruit and vegetables ( Lee and Kader 2000) Vitamin C is measured as percentage of ascorbic acid An average value of vitamin C content in strawberry is 60 mg/100 g of fruit, values can vary widely amon g cultivars, studies in Japan has shown values ranging from 15.9 to 114.8 mg/100 g of fruit weight (Sone et al., 1999). S everal other factors can affect t he vitamin C content in fruits and vegetables including preharvest conditions such as cultural practi ces F or example t he higher the intensity of light during the growing season, the greater is vitamin C content in plant tissues. (Lee and Kader, 2000). Postharvest procedures can also affect vitamin C content Elevated temperatures during storage increase vitamin C losses (Vinokur et al., 2002) Visual appearance is subjective assessment of calyx appearance, water loss and sheen to rate the overall appearance of the fruit inside each clamshell, to determine the percentage of marketable fruit. Deterioration of strawberries is caused by injuries from harvesting, handling, decay and natural senescence (Kader, 2002) Management of temperatur es influence strawberry quality has been reported that s trawberries stored in semi constant temperature had less weight wa ter loss, less shriveling, and less incidence of bruising compared with those stored in fluctuating temperatures (Nunes et al., 2003) There is also a cultivar effect on appearance rating for postharvest quality for strawberries (Plott o and Chandler, 2006) Firmness of the fruit is determined by a n Instron penetrometer to measure individual firmness of the fruit based on the resistant of the flesh to deformation by the probe, values were expressed in Newton (N) F irmness then measure the resistance of the f ruit to mechanical damage. Has been reported that strawberries with different maturity stage has different firmness,

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27 strawberries were firmer at 3/4 red maturity level with a mean stress of 0.136N/mm 2 compared with fruit at 4/4 red with a mean stress of 0. 098N/mm 2 (Gunness et al., 2009) Importance of the S tudy Florida is the second largest producer of strawberry in United States, and it is the main supplier for the eastern United States and Canada during the winter. With urban development, space for agricu lture in the state is shrinking, so there is a pressing need to produce more on the same piece of land or in a smaller area. Protective structures, especially high tunnels and greenhouses are very popular worldwide for strawberry production, and might help to increase the yields and quality of strawberry fruit produced in the U.S. (Kadir et al, 2006). Per capita consumption of strawberry in the U.S. is 2.7 kg per person (USDA,2007), and taking into account its high vitamin C content, amongst other health b enefits, this quantity may increase with an appropriate marketing campaign (University of Illinois Extension, 2008). There have been many reported benefits of using high tunnels on different crops in different locations; however, there is no research avai lable on its application for strawberry in Florida. This study compares the performance of three cultivars, grown in high tunnels and the open field at Balm, Florida, with respect to plant growth, yield, fruit quality and postharvest shelf life.

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28 C HAPTER 3 EFFECTS OF HIGH TUNN EL PRODUCTION ON FLO RIDA STRAWBERRY GROW TH, YIELD AND POSTHARVES T QUALITY. Materials and Methods This study was conducted from October to March on the 2007 08 and 2008 09 seasons at the Gulf Coast Research and Education Center of the University of Florida, Balm, Florida. T he soil used for the experiment is a fine sandy Spodosol with <1.5% organic matter and pH of 7.2. Planting beds were pre formed with a standard bedder, 71 cm wide at the bas e, 61 cm wide on the top, and 25 cm high. In Sept ember 2007, the soil was fumigated with 392 kg/ha of methyl bromide + chloropicrin (67/33, v/v). After the fumigant injection, beds were covered with black high density polyethylene mulch. No pre plant fertilizer was used. Fertilization and pest contr ol was done according to the requirements of the crop (Peres et al., 2006). Fertigation was applied t h rough a single drip tape line (0.056 L/m/min) buried 5 cm, and the experimental area was equipped with 15 L/min sprinklers for frost protection and crop e stablishment. A factorial set of six treatments (three strawberry cultivars x two production systems) were tested. The experimental design was a split plot design with 4 replications on 2007 08 season and 6 replications on 2008 09 season. P roduction syste m s were the main plots, and cultivars were the subplots. The production systems used were high tunnels and open field; and the cultiv P assively ventilated tunnels ( 5 m high, 8.5 m wide and 91 m long ) were utilized for this study (Haygrove Tunnels, Herefordshire, United Kingdom). Bare root strawberry transplants from nurseries in Canada were planted o n 15 October for both seasons, in double rows 38 cm apart, 20 plants per 7.6 m plot. After t ransplanting, overhead irrigation was used for 8 hours for the first 10 days to ensure plant establishment ( the amount of water used was approximately 480,000 L/ha/day).

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29 Strawberry plant diameters and chlorophyll content readings were taken at 8 and 12 we eks following transplanting. G reenness of leaves was measured with a SPAD 502 (Minolta, Ramsey, New Jersey, U SA ) a numerical SPAD (Soil Plant Analysis Development) unit, ranging from 0 to 80 is calculated by the chlorophyll meter and used to estimate the chlorophyll content S trawberries with the calyx attached, a minimum of 80 % red, over 10 g in weight, free of mechanical defects, insects or disease were considered marketable. Market able fruit weight and number were measured, two times per week for a tot al of 30 harvests during the season. Early yield was considered as the yield from the first 10 harvests, and the total yield included the 30 harvests through the season. After freeze or near freeze events the y ield data on the six following harvests was re corder. Postharvest data was collected with fruit harvested on February 11 18 and 25, and March 17 and 24 for 2007 08 season. Fruits were harvested at the Gulf Coast Research and Education Center at Balm, Florida, and transported to the Horticultural Scie nces Department in Gainesville, and stored overnight in a cooler at 7.2 o C to be processed the next day. For season 2008 09, fruits were harvested on January12 and 26, February 9, 18, and 23, and March 16 and processed on site at the Gulf Coast Research an d Education Center. Storage temperatures for strawberries should be close to 0 o C, with minimum temperature fluctuation to maximize shelf life up to two weeks to allow the fruit to reach the market in good condition (Kader, 2002). In this study strawberry fruits were stored in plastic clamshells in a cooler at 7.2 o C for eight days. This temperature is notably higher than the recommendation, with the intention to force postharvest decay. Fully red f ruit s were stored i n 946 mL and 473 mL clamshells (Highland Corporation, Inc., Mulberry, Florida, U SA ) on season 20 07 08 and 2008 09, respectively. For 2007 08 season three fruit per treatment were taken and the external color

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30 was measured on both sides of the fruit with a Minolta CR 400 chroma meter (Minolta, Ram sey, New Jersey, USA) C olor was expr essed as lightness (L*) value hue angle value and chroma (C*). T hen the calyx was cut off, and the firmness (3 mm deformation) of the center 1 0 mm slice lengthwise was measured on both sides with an Instron 4411 (Instr on Corporation, Norwood, Massachusetts, USA), equipped with a 3 mm diameter tip and 5 kg load cell was used, crosshead speed was 0.83 mm s 1 This test measured individual fruit firmness based in the resistance of the tissue to deformation by the probe. F ruit stored in the clamshells were subjective ly assessed for v isual appearance as an a verage of subjective assessment of calyx appearance, water loss and sheen to rate the overall appearance of the fruit inside each clamshell, to determine the percentage o f marketable fruit with the idea of simulat ing when a consumer buys strawberries at the supermarket. The scale used for marketable attributes ranged from 0% (when there was no marketable fruit), 20%, 40%, 60%, 80% and 100% (when all fruit was marketable a s harvest fresh). The percentages represent the percentage of the fruit inside the clamshell that is saleable based on the variables mention above. Simultaneously, six fruit per treatment were frozen before and after storage to be processed at the end of t he season. Frozen samples were defrosted at room temperature, blended in a Hamilton Beach Model 908 blender (Proctor Silex, Inc, Washington, North Carolina, U.S.A.), and centrifuged on a Beckman Model J2 21 centrifuge (Beckman Coulter, Inc., F ullerton, Cal ifornia, U.S.A.). T he juice obtained was frozen in 20 ml plastic vials for later evaluation s Analyses made with the juice were replicated 3 times to assure precision. S oluble solids content ( B rix ) was measured by Abbe Mark II digital refractometer (Misco Refractometer, Cleveland, Ohio, U.S.A.), using a drop of unfrozen extract. pH and acidity were measured diluting 6 ml of sample on 50 ml of distilled water and stirred with a Metrohm 728

PAGE 31

31 stirrer (Metrohm USA, Inc, Westbury, New York, U.S.A. ) and titrated with Titrino 719 S (Metrohm USA, Inc, Westbury, New York, U.S.A.). T otal t itra ta ble acidity was calculated as citric acid. Vitamin C was measured for three sampling dates, February 18, February 25, and March 24. Vitamin C content was measured using 2 m L of sample and following the AOAC On 2008 09 season b efore and after storage color and soluble solids content were measured, thr ee fruits per treatment were taken; the external fruit color was measured as mentioned above To measure s oluble solids content the tip of each fruit (0.5 cm) was cut and the fruit was squeezed, the juice obtained was used for the measurement with a digita l hand held pocket refractometer Model PAL 1 (Atag o USA, Inc., Washington, USA). This procedure of measure soluble solids was used because it is a practical form of determination of soluble solids and can be easily replicated in the field and for growers. F ruits stored in the clamshells were assessed to determine marketable fruit using the same cri teria than the anterior season. Collected parametric data were analyzed using Statistix 9 software (Analytical S oftware, Tallahassee, Florida, USA) general linear model procedure to determine if there were signific ant differences between production system s and if there were any production system x cultivar interactions. significance level. Data with percentage unit was transformed with arcsin 1 and then analyzed. Measurements of pH were transformed to log base before its analysis, and after the statistical analysis the numbers were transformed back to the original units.

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32 Results and Discuss ion 2007 08 Season For 2007 08 season the Florida Automated Weather Network (FAWN) report that October started with warm temperatures with minimum of 18 o C maximum of 34 o C (Table 3 1). By the end of November minimum temperatures descend to 4.6 o C and maxim um temperatures around 30 o C. At the beginning of January (week 12) temperature dropped to 2.6 o C afterwards minimum temperatures were in the range of 2 to 11 o C, and maximum were around 30 o C (for daily average s see Appendix A). The data collected from t emperature sensors installed inside the high tunnels and in the open field, show a similar pattern, with an average of 1 to 5 o C difference between the systems. FAWN report five rainfall events with more than 25 mL of rain (January 19 and 23, February12 an d 23, March 7). Plant diameter and chlorophyll content Production systems and cultivars had significant effect s on strawberry plant diameter and chlorophyll content (Table 3 2 ) However, the re were no significant production systems x cultivar interaction effect on these variables. Plants inside high tunnel s were 19 and 18% wider than plants growing i n the open field at 8 and 12 weeks after transplant respectively. widest r respectively Chlorophyll content was an 8% higher i n the high tunnel than in open field at 12 ntent at 8 weeks with 45.2 weeks after transplant with 43.7 and 43.3 SP with 41.3 SPAD value

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33 Yields Strawberry yields were significant affected by production systems and cultivars (Tab le 3 3 and 3 4 ) However, there were no significant production systems x cultivars effects Early yields On January 3 (12 WAT) there was a freeze event. During that night temperature outside the high tunn els were recorded as low as 2.6 o C (Figure 3 1 ). For t he six harvests following this freeze event the yield inside the high tunnel was 74% higher than in the open field. Six harvests after the free with 1.5 4). T otal yields were 64% higher i n high tunnels than in the open Festiva ad the highest of 12 .4 t/ha, 9.4 t/ha and 7.7 t/ha Color There were five storage tests for five harvest times. For the fruit harvested on February 11 (17 WAT) production systems ha d no significant effect on light ness (L*) chroma and hue angle values, before and afte r the storage. ( Figures 3 2, 3 3 3 4 3 5, 3 6, 3 7, 3 8, 3 9 and 3 10 ). However, cultivars varied significantly in the color of their fruit ness values of 32.8, 31.5 and 31.3 respectively before storage and values of 34.7, 33.6 and 33.4 after storage. values of 4 1.3, 38.9 and 37.3, respectively. A fter storage there was no significant diffe rence in chroma among cultivars higher hue angle value, than with val ues of 33.3, 29.9 and 28.2 respectively before storage, and 33.8,

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34 27.9, and 28.6 respectively after storage (Figures 3.7, 3.8 and 3.9). There were no significant production systems x cultivars effects on fruit color. For the storage test on fruit harveste d February 18 (18 WAT) production systems had no significant effect on light ness chroma and hue angle values, before and after the storage. Values of light ness were 33.5 and 32.5, chroma 36.5 and 35.6, and hue angle values of 29.4 and 29.0, before and af ter storage respectively. There was no significant difference among cultivars on light ness values before and after storage Chroma values before storage were similar and higher on than o similar to with values of 37.4, 34.6 and 34.5, angle values, values were 32.0, 29.1 and 27.2 respectively. After storage the hue angle the interaction between production systems and cultivars was not significant. For light ness values on fruit harvested on February 25 (19 WAT) production systems had significant effect after storage, with values of 32.9 in high tunnels and 34.4 in the open field. There was not significant effect of production systems on light ness before storage, chroma and hue values Cultivars had a significant effect for light ness before and after storage, chroma

PAGE 35

35 respectively. However, the interaction between production systems and cultivars was not significant. Production systems for the storage test on fruit harvested on March 17 (22 WAT) had sign ificant effect on chroma before storage with values of 38.0 for high tunnels and 36.2 in the open field. There was not significant effect on light ness before and after storage, chroma after storage and hue angle values before and after the storage, with val ues of light ness of 32.9 before and 33.8 after storage, chroma of 36.4 after storage, and hue angle values of 28.9 and 30.5, before and after storage respectively. Cultivars had a significant effect on fruit color before and before and after the storage, with values of 34.7, 31.7 and 32.2 before storage and 35.4, 32.9 and 33.0 after storage D 39.7, 35.1 and 34.3 after storage angle values angle values of 3 2.1, 29.5, and 27.9 before storage, and hue angle values of 32.9, 27.3 and 28.5 after storage, respectively. However, the interaction between production systems and cultivars was not significant. Color measurements on fruit harvested on March 24 (23 WAT) showed no significant effect of the production systems on light ness chroma and hue angle before and after storage. The average values for light ness chroma and hue angle were 34.3 and 34.0, 35.5 and 37.0, and 30.0 and 31.1 before and after storage, respec tively. Cultivars had significant effects on light ness and

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36 light ness storage, and respectively. C ultivars had no significant effects on light ness and chroma values before storage, and hue angle values before and after storage, the average values were 34.3 for light before storage, 35.9 for chroma before storage, 29.6 and 31.1 for hue angle before and after storage respectively. However, the interaction between production systems and cultivars was not significant. Fruit firmness Fruit firmness was not significantly different between production systems or among cultivars before and after storage for th e five harvests tested (Figures 3 11, 3 12 and 3 1 3 ). Also the re were no significant interaction effects Fruit harvested on February 11 (17 WAT) the firmness average values for 3 mm deformation were 0.62 and 0.74 N before and after the storage. The firmn ess average values for fruit harvested on February 18 (18 WAT) were 0.79 and 0.86 N before and after storage. Fruit harvested on February 25 (19 WAT) had firmness average values of 0.49 and 0.61 N before and after storage. Firmness on fruit harvested on M arch 17 (22 WAT) average values of 0.72 and 0.81 N before and after storage. Fruit harvested on March24 (23 WAT) firmness average values were 0.65 and 0.79 N before and after storage respectively M arketable fruit The marketable fruit evaluation after 8 days storage was done within cultivar on both systems F days storage (Figure 3 14 ). For the harvest on February 18 (18 WAT) the clamshells from open field had 50% of ma rketable fruit compared with a 60% marketable fruit inside the high tunnel after the storage. On February 25 (19 WAT) open field had 60% of marketable fruit after storage

PAGE 37

37 compared with 45% marketable from high tunnel. On March 17 (22 WAT) fruit from open f ield was 60% marketable after storage, meanwhile, there was 50% marketable fruit from inside the high tunnel. On March 23 (23 WAT) fruit from open field was 60% marketable after storage in contrast with 40% from the high tunnel. produ ction systems had significant effects after storage on the fruit harvested on February 25 and March 17, the clamshells from inside the high tunnel had 50% and 40 % marketable fruit compared with 40% and 50% marketable fruit in open field, respectively (Fig ure 3 15 ). Production systems had significant effects on marketable fruit after storage for marketable fruit was 60% and 60% in comparison with 40% and 50% in open fie ld for both dates respectively (Figure 3 16 ). Soluble solids S oluble solids content varied significantly among cultivars for fruit harvested on February 11 (17 WAT) both before and after storage. Ho wever, production system had no effects on s oluble solid s content, and the interaction between factors was not significant. Before and after soluble solids (Figures 3. 1 7, 3 18 and 3 19 ). Fruit harvested on Feb ruary 18 (18 WAT) illustrate significant effects of cultivars on soluble solids content after storage. Nevertheless, production systems had not effects on soluble solids content, and the interaction between factors was significant for soluble solids conten t after soluble solids content with 8.4 o Brix followed by o o Brix before storage. After the highest soluble solids content with 7.9 o

PAGE 38

38 values of 7.2 and 7.1 o tunnel, with values of 6.3 and 6. 0 o soluble solids content with 5.4 o Brix. Production systems had significant effects soluble solids content for fruit harvested on February 25 (19 WAT) after storage. Cultivars had effects on fruit solub le solids content before and after storage. However, the interaction between both factors was no significant. Fruit produced in open field had higher soluble solids content after storage than fruit from inside the high tunnel, with values of 5.3 and 4.8 o B soluble solids soluble solids content, with values of 5.9, 5.1 and 4.2 o Brix before storage and soluble solids content of 5.9, 4.9 and 4.3 o Brix after storage. Cultivars had significant effects on soluble solids content for the fruit harvested on March 17 (22 WAT) before and after storage. However, production system had no significant effects on s oluble solids content, and the interaction between both factors was no significant. Before soluble solids o Brix, respectively. After storage t soluble solids content with 8.2 o soluble solids content of 6.3 and 6.2, respectively. Interaction among production systems and cultivars was significant for s oluble solids content on fruit h arvested March 24 (23 WAT) before storage. After storage cultivars had significant effects on s oluble solids content and production system had no effects. Before storage ad the highest s oluble solids content with values of 7.6, 6.9 and 7.4 o

PAGE 39

39 soluble solids content with 5.3 o Brix. After storage oluble solids content with 6 .9 o o Brix. T otal t itratable acidity Production systems had significant effects on total titratable acidity (expressed as citric acid) measured on strawberry before and after the stor age for fruit harvested on February 11 (17 WAT) The interaction between production systems and cultivars w as not significant (Figures 3 20, 3 21 and 3 22 ). Citric acid content on fruit inside the high tunnel was 15% superior compared with fruit in the ope n field before storage, on fruit after storage de citric acid content was 24% higher inside the high tunnel than open field. Cultivars had significant effects on fruit acidity before and after storage for fruit harvested on February 18 (18 WAT) However, the interaction between producti on systems and cultivars was no before st orage and 0.75, 0.77 and 0.63% citric acid after storage, respectively. Before storage cultivars had significant effects on acidity content for fruit harvested on February 25 (19 WAT) although, the interaction between production systems and cultivars was no significant. After storage, the interaction between both factors was significant. Before storage 0.72 and 0.57 % citric acid, respectively. After storage the gr eater citric acid content was found tent inside the high tunnel and in open field with 0.64 and 0.72 % citric acid.

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40 For fruit harvested on March 17 (22 WAT) cultivars had significant effects on strawberry fruit citric acid content after storage. However, the interaction between production s ystems and cultivars was not significant before and after storage. Before storage, the average citric acid Production system had significant effects on citric acid content after storage for fruit harvested on March 24 (23 WAT) Cultivars had significant effects on citric acid content before and after storage. However, t he interaction between both factors was no significant. Inside the nd 0.65 % citric acid before storage, and 0.91, 0.70 and 0.69 % citric acid after storage. For the five storage test s pH was also measured before and after storage but there was not a clear trends on the results (see appendix B) Vitamin C Vitamin C conten t for fruit harvested on February 11(17 WAT) was affected by production systems and cultivars before storage, there was no interaction between both factors. After storage the interaction among both factors was significant for vitamin C content (Figures 3 2 3, 3 24, and 3 25 ). Before storage the vitamin C content on fruit inside the high tunnel was 13% higher than 24.9 and 21.5 mg/100 g, and the lowest content was on with an average content of 13.6

PAGE 41

41 The interaction between production systems and cultivars was significant on fruit harvested on February 25 (19 WAT) for vitamin C content before stor age. After storage production systems and cultivars had significant effects on vitamin C content, however, the had vitamin C values of 21.3 and 19.8 mg/100 18.2 mg/100 g, resp ectively. After storage the vitamin C content in strawberry fruit produced 1 and 14.6 mg/100 g, respectively. Before and after storage production systems had significant effects on strawberry fruit vitamin C content for fruit harvested on March 24 (23 WAT) Cultivars had significant effects on vitamin C content after storage. Ho wever, the interaction between both factors was not significant before and after storage. The vitamin C content of strawberry fruit produced inside the high tunnel was 25% higher than open field before storage, and 15% higher after storage. Before the stor was also Strawberry plants grown in high tunnel were wider than plants in open field production. These results confirm that high tunnels p romote more growth in the plants than field conditions

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42 (Kadir et al., 2006). Since the PAR inside the tunnel is lower inside the tunnel this might be causing etiolating of the plants, plant elongate trying to reach more light. Chlorophyll content in plant leaves was higher in plant inside the high tunnel compare with the open field. In average SPAD values suggest that plants are growing in a normal range, considering the r elation between SPAD value and chlorophyll content for strawberry (r 2 =0.92) (Hilmerick et al., 1992) Yields The results obtained in this study correspond with previous research w h ere high tunnel conditions produce early strawberries and marketable fruit was greater inside than outside the high tunnels (Kadir et al 2006). The increase in the marketable yie ld is led by the tunnel protection (Lutchoomun and Cangy, 1997). A key advantage of high tunnel production is the exclusion of rainfall, which can detrimentally influence product quality (Montri and Biernbaum, 2009). Fruit color was not different in high t unnel and open field production system before and angle values followed the same pattern. Differences in color were capt ured by the colorimeter, but they could not be distinguished by comparing fruit side by side under bare eye, which means color could not be used as a variable to compare fruit from both systems. Production systems and cultivars had no effects on strawberry fruit firmness before and after storage this might be due to different ripe stages of the fruit at sample time Production systems had effects on marketable fruit Cultivars had effect on marketable fruit for two of the four storage test.

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43 Production systems had no effects on strawberry fruit s oluble solids content before and after the storage. Cultivars had effects on s oluble solids oluble solids con In general, production systems had little or no effects in strawberry fruit total titratable acidity. Cultivars had effects on fruit total titratable acidity. Production systems had significant effects on fruit vitamin C content; fruit from inside high tunnel had more v itamin C than fruit from open field. Cultivars had effects on v itamin C content. However there was int eraction between both factors on 2 sampling dates, out of six. Previous research on strawberry in high tunnels report highest total titratable acidity and s oluble solids content and highest Vitamin C values in high tunnels (Voca et al, 2007). In Balm for t he season 2007 08, there were differences between systems only for vitamin C values, with highest values on fruit from high tunnel. There were also differences between cultivars. 2008 09 Season For 2008 09 season FAWN report that October started with warm temperatures with minimum of 12 o C maximum of 29 o C (Table 3 5 ), minimum temperature dropped to 1.6 o C on the last week of October. November and February minimum temperatures range in average from 0 to 5 o C and maximum temperatures from 25 to 30 o C. March te mperatures rise with minimum temperatures reaching 11 o C and maximum of 31 o C (for daily averages see Appendix A) During this season three freeze events occur January 21 to 23, February 5 and 21, with minimum temperatures of 3, 5.6, 5, 2.8 and 0.6, r espectively. The data collected from temperature sensors installed inside the high tunnels and in the open field, show a similar pattern, with an average of 1 to 5 o C difference between the systems. FAWN report two rainfall events with more than 25 mL of r ain ( November 30 and December 11 ).

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44 Plant diameter and chlorophyll content Production system had significant effects on strawberry plant diameter and chlorophyll content in leaves at 12 weeks after transplanting (Table 3 6) Strawberry cultivars had effects on strawberry plant diameter and chlorophyll content in leaves at 8 and 12 week after transplant. However the interaction between the two factors was no significant. Plants inside the high tunnel were 10.7% wider than plants in the open field at 12 weeks had the widest after transplant with 35 cm d cm. Chlorophyll content was 2.3% higher on strawberry plants inside the high the h igher chlorophyll content at 8 weeks after transplant with of 48.5 and 48.5 SPAD value, Yields On early yields and total yields production systems and cultivars had significant effects. However, the interaction between both factors was not significant (Table 3 7) Early yield inside Total yield was 50% superior ins with 9.0 t/ha and 8.4 t/ha, respectively.

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45 During th e strawberry season there were three freeze o near t o freeze events, January 21 to January 23, February 5 and 21 (Table 3 8 ), after these freeze events the yield data for the following six harvests was collected. Interaction among production systems and cultivars were significant. After the first freeze eve n open field had the lowest yield after the with 3.7 t/ha, the trea field, with yields of 1.7 and 1.1 t/ha, respectively. Color Color measurements were taken to the strawberry fruits before and after the storage test for five harvest times (Figure s 3 26, 3 27, 3 28, 3 29, 3 30, 3 31, 3 32, 3 33 and 3 34) For the fruit harvested on January 12 ( 13 WAT) production systems had significant effects on light ness before storage and chroma before and after storage. Cultivars had significant effects on light nes s after storage, chroma before and after storage, and hue angle after storage. However, the interaction between production systems and cultivars was no significant. Fruit from inside the high tunnel had 5.4% lighter color, than fruit from open field before storage, chroma values were 3.9% and 10.4% higher inside the high tunnel before and after storage respectively. Light ness ness value.

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46 angle value after storage angle 24.8 hue angle angle value. Light ness values on strawberry fruit after storage, and hue angle values before and after storage were significantly affected by production system on fruit harvested on January 26 (15 WAT) Cultivars had significant effects on light ness values before and after storage, chroma values after storage, and hue angle values before and after storage. However, the interaction between both factors was significant only for chroma values be fore storage. Light ness values on fruit after storage inside the high tunnel were 4.9% greater than fruit in open field hue angle values were 4.9% superior before storage and 7.2% higher after storage in fruit from inside the high tunnel compared with fru ness value before ness values. After storage the peak light ness Festi ness value ness value. Chroma values after storage was higher on with 34.9 hue angle angle value before and after averages of 25.7 and 25.2 before and after storage res pectively. Chroma before storage was the

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47 with an average value of inside the high tunn el and open field, with 35.3 average chroma value. On February 9 (17 WAT) systems, and therefore the ana inside the high tunnels and in open field. Production systems had significant effects on hue angle values after storage; and cultivars had significant effects on chroma and hue angle values aft er storage. Interaction between both factors was significant for chroma and hue values before stora ge. Production systems had no significant effects on light ness values. Before storage the average light ness value was 35.5 and after storage the average ligh t ness value was 33.2. The hue angle value after storage was 0.8% greater in fruits from inside the high tunnels compared with angle value than inside t e greater hue values with angle value and was angle value was 25.8 found in el. For fruit harvested on February 23 (19 WAT) production systems had significant effects on light ness and hue angle values after storage. Cultivars had significant effect on light ness after

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48 storage, chroma before and after storage, and hue angle after s torage, and the interaction between both factors had significant effects only on light ness and hue angle before storage. The fruit from inside the high tunnel was 6.1% lighter after storage than fruit from open field. Hue angle values inside the high tunne ness value after storage averaging 34.3 light ness value, followed by ness highest 35.5 and 36.9, respectively. Hue angle light ness high tunnel with 37.2 and 36.9 light ness values, respectively, the lowest values were founded on ness values. For hue angle values 33.2 hue angle the high tunnel and in open field, with 26.4 average hue angle value. Production syst ems had significant effects on light ness chroma and hue angle after storage for strawberry fruit harvested on March 16 (22 WAT) Cultivars had significant effects on light ness chroma and hue angle before and after storage. However, the interact ion betwe en both factors was no significant. The light ness value on fruits from inside the high tunnel after storage was 34.0 compared with 33.3 in open field. Fruit from inside the high tunnel after storage had a 4.7% greater chroma value than open field, with 37. 4 and 35.7, respectively. Hue angle values

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49 highest light ness 32.9 light ness values. After storage light ness value was the highest in ness ter after storage. Hue angle angle value angle value angle value before storage and 24.4 after storage. Ma rketable fruit For the marketable fruit evaluation after storage the analysis was done within c ultivar on both systems (Figures 3 35, 3 36 and 3 37) effects only on fruit harvested on February 9 (17 WAT ) after 8 days in storage. Fruit from open (19 WAT) the clamshells from in side the high tunnel had 43% marketable fruit compared with 23% storage for fruit harvested on January 12, February 9 (17 WAT) and March 16 (22 WAT) inside the h igh tunnel the marketable fruit was 67, 63 and 53% compared with 27, 27 and 40% in open field for the three dates, respectively.

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50 Soluble solids S oluble solids content was measured in fruit before and after the five storage tests at five different harvest times (Figure 3 38 3 39 and 3 40 ). For the fruit harvested on January 12 (13 WAT) production systems and cultivars had significant effects on strawberry s oluble solids content after storage, and there was an interaction between the factors for the solubl e solids content before storage. The s oluble solids content of the fruit from inside the high tunnel was soluble solids content with 8.9 o Brix after storage, followed b o Brix and o oluble solids content before storage, w ith values of 9.7, 9.1 and 9.7 o Brix. The lowest s oluble solids content o Brix. S oluble solids content on fruit harvested on January 26 (15 WAT) showed no significant effect of productio n system before or after storage. Cultivar had significant effect on s oluble solids content before and after storage. However, the interaction between both factors was not oluble soli ds content before storage and after storage with an average of 10.1 and 11.0 o Brix, respectively, than and 9.5 o Brix, before and after storage respectively. The interaction between productions systems and cultivars was significant b efore and after the storage on fruit harvested on February 9 (17 WAT) the greater s oluble solids content 13.3 o Brix, follo with values between 10.4 and 11.2 o

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51 had the highest s olubl e solids content with 13.4 o field with values from 10.6 to 11.6 o Brix. Before and after storage the interaction between product ion systems and cultivars was significant on s oluble solids content for fruit harvested on February 23 (19 WAT) Before o inside the high tunnel with 10.6 o Brix o Brix, the lowest s oluble solids content before storage was 7.4 o oluble solids content 12.4 o Brix, Cultivar and production systems had significant effect on s oluble solids content for the fruit harveste d on March 16 (22 WAT) before and after storage. However, the interaction between both factors was not significant. S oluble solids content on fruit from inside of the high tunnel was superior than fruit from open field, the values inside the high tunnel we re 19.0% and 19.5% greater than open highest s oluble solids content before and after storage with values of 10.7 and 10.3 o Brix, h averages of 8.5 and 7.7 o Brix before and after storage, respectively. Strawberry plants grown inside the high tunnel were wider than plants grown in open field. Chlor ophyll content in strawberry leaves were similar o higher on plants inside the high tunnel

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52 Fruit harvested at different times (13, 15, 17 and 19 weeks) was stored for 8 days at 7.2 o C, and were later ana lyzed for a number of variables S oluble solids content of these samples was highest s oluble solids both systems, before and after storage. Hue angle was similar or had less marketable fruit after storage than in open field. In conclusion there were significant effects when strawberries were cultivated inside high tunnel at the Researcher Center (Balm, FL). Plants were wider, and produce more fruit in all the cultivars tested, as reported in other studies (Kadir et al., 2006; Lutchoomun and Cangy, 2008). Fruit inside the tunnel for the freeze event was protected from low temperatures and wind; and there was not damage on plant or fruit after the cold event inside the tunnel. No water was used inside the tunnel to prevent freeze compared with the ten nights of water used for open field production (in average in one night of sprinkler frost protection 627 ,000 liter per hectare of water are used), which suggests that implementation of high tunnels might improve water use efficiency while keeping good quality production. For the postharvest study fruit from inside the tunnels had higher s oluble solids content, and for two of the cultivars the marketability after storage inside the tunnel was similar o r better than in o pen field. However, more research needs to be done for other cultivars, and other locations. An economical analysis is needed to determine if the cost benefit of the implementation of this practice for growers.

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53 Table 3 1. Data from temperature sensors loc ated in open field and high tunnel at 10 cm height, and temperature from FAWN weather report, for Balm during 2007 08 season. Date Week Tunnel Open field FAWN Temperature ( o C) Avg. Min. Max. Avg. Min. Max. Avg. Min. Max. 17 Oct 07 Week 1 N/A N/A N/ A N/A N/A N/A 25.0 17.9 33.5 24 Oct 07 Week 2 N/A N/A N/A N/A N/A N/A 23.7 17.7 32.8 31 Oct 07 Week 3 N/A N/A N/A N/A N/A N/A 21.9 9.3 29.3 07 Nov 07 Week 4 18.0 7.8 29.1 17.7 7.4 28.7 16.2 5.6 26.9 14 Nov 07 Week 5 18.6 7.4 29.5 18.4 6.6 29.1 17.3 4.6 28.1 21 Nov 07 Week 6 21.7 12.6 31.1 21.4 12.2 31.1 20.1 11.6 29.2 28 Nov 07 Week 7 21.2 9.0 31.9 20.8 8.6 31.1 21.4 15.4 30.3 05 Dec 07 Week 8 20.8 7.8 31.9 20.5 6.2 31.1 18.4 4.3 29.4 12 Dec 07 Week 9 19.3 3.7 33.2 18.8 2.9 31.5 21.6 8.4 29.8 19 De c 07 Week 10 19.3 11.4 31.5 18.2 9.8 27.9 15.2 2.3 26.2 26 Dec 07 Week 11 21.6 10.2 33.2 20.9 9.4 31.1 19.8 11.9 28.8 02 Jan 08 Week 12 14.9 0.6 31.5 13.5 1.1 28.7 13.5 2.6 26.2 09 Jan 08 Week 13 19.3 5.4 33.2 18.0 2.9 29.9 19.5 9.4 28.5 18 Jan 08 W eek 14 18.5 10.6 24.4 17.2 4.2 28.7 15.5 2.8 27.1 25 Jan 08 Week 15 N/A N/A N/A 15.2 3.7 28.7 16.5 4.6 27.1 01 Feb 08 Week 16 N/A N/A N/A 19.9 7.0 31.5 16.9 2.7 28.8 08 Feb 08 Week 17 N/A N/A N/A 17.8 4.2 27.1 19.8 7.8 29.5 15 Feb 08 Week 18 N/A N/A N/ A 18.6 7.0 31.1 17.0 3.7 29.1 22 Feb 08 Week 19 N/A N/A N/A 20.4 5.4 31.1 19.7 6.7 29.0 29 Feb 08 Week 20 N/A N/A N/A 18.7 3.7 30.7 16.3 1.6 28.2 07 Mar 08 Week 21 N/A N/A N/A 18.3 4.2 31.1 18.4 3.7 29.7 14 Mar 08 Week 22 N/A N/A N/A 21.8 9.0 34.0 19.6 8.4 30.2 21 Mar 08 Week 23 N/A N/A N/A 18.0 3.3 31.5 20.7 10.6 29.6 28 Mar 08 Week 24 N/A N/A N/A 23.1 12.9 36.1 20.7 10.6 29.6

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54 Table 3 2 Effects of production systems and strawberry cultivars on chlorophyll content and plant canopy diameter a t 8 and 12 weeks after transplanting (WAT). 2007 08 Season Z Values followed by the different letters represent significant difference s among treatments Diameter Chlorophyll content cm SPAD value Production Systems 8 WAT 12 WAT 8 WAT 12 WAT Tunnel 26 a Z 33 a 43.7 41.2 b Open field 22 b 28 b 44.4 44.4 a P value 0.0032 0.0079 0.4127 0.0048 C ultivars 28 a 34 a 43.0 b 41.3 b 23 b 30 b 44.0 b 43.3 a 20 c 26 c 45.2 a 43.7 a P value <0.0001 <0.0001 0.0029 0.0004

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55 Table 3 3 Effects of production systems and strawberry cultivars on early yield and total yield. 2007 08 Season Early yield Total yield Production Systems ----------t /ha ---------Tunnel 2.0 a Z 12.2 a Open field 1 .3 b 7.5 b P value <0.0001 <0.0001 Cultivars 2.4 a 12.4 a 1.6 b 9.4 b 1.0 c 7.7 c P value <0.0001 <0.0001 Z Values followed by the different letters represent significant differences among treatm ents

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56 Table 3 4. Effects of production systems and strawberry cultivars on yield 6 harvests following a freeze or near freeze temperature event on January 3 when temperature dropped to 2.6 o C 2007 08 Season Yield after freeze Produ ction Systems (t /ha ) Tunnel 1.4 a Z Open field 0.8 b P value 0.0001 Cultivars 1.5 a 1.3 b 0.7 c P value <0.0001 Z Values followed by the different letters represent significant differences among treatments

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57 Table 3 5. Data from temperature sensors located in open field and high tunnel at 10 cm height, and temperature from FAWN weather report, for Balm during 2008 09 season. Date Week Tunnel Open Field Fawn Temperature ( O C) Av g. Min. Max. Avg. Min. Max. Avg. Min. Max. 20 Oct 08 Week 1 21.7 14.1 27.9 21.8 13.7 28.3 22.2 12.9 29.1 27 Oct 08 Week 2 16.2 4.2 27.1 16.2 3.7 27.5 15.9 1.6 27.4 3 Nov 08 Week 3 19.2 11.0 28.7 19.1 10.6 29.1 18.8 9.9 28.9 10 Nov 08 Week 4 20.2 7.4 32 .3 20.8 7.4 32.8 20.4 3.1 32.0 17 Nov 08 Week 5 12.8 2.9 24.8 12.8 2.9 24.0 12.0 0.8 23.6 24 Nov 08 Week 6 15.7 5.0 28.3 15.5 4.6 28.3 14.7 0.6 27.2 1 Dec 08 Week 7 15.4 3.3 26.0 15.3 2.9 26.7 14.7 1.3 26.3 8 Dec 08 Week 8 17.2 5.0 30.3 17.1 4.6 30.3 1 6.9 3.0 29.2 15 Dec 08 Week 9 20.0 11.8 31.1 19.4 11.4 28.3 18.9 9.5 27.4 22 Dec 08 Week 10 19.9 6.6 31.5 19.4 6.6 30.3 19.0 6.1 28.5 29 Dec 08 Week 11 18.8 8.2 31.5 17.9 7.8 28.3 17.5 5.3 27.3 5 Jan 09 Week 12 18.5 7.0 34.4 17.4 6.2 30.3 16.8 4.0 29.0 12 Jan 09 Week 13 13.5 2.9 31.9 12.4 2.5 26.0 12.0 1.6 25.7 19 Jan 09 Week 14 14.0 1.2 31.1 11.3 0.2 28.7 10.7 4.7 26.1 26 Jan 09 Week 15 18.7 3.7 32.8 16.6 2.5 29.1 16.4 1.4 28.4 2 Feb 09 Week 16 13.7 1.1 29.1 11.0 1.1 26.0 10.7 2.7 24.2 9 Feb 09 Week 17 20.9 8.2 37.0 19.0 6.6 31.1 18.6 5.4 29.5 16 Feb 09 Week 18 17.4 3.3 32.3 15.9 2.9 26.3 15.4 0.2 24.8 23 Feb 09 Week 19 18.8 6.2 36.6 17.1 5.4 30.3 16.4 4.9 28.4 2 Mar 09 Week 20 17.6 2.9 38.8 15.5 2.0 31.9 14.5 1.0 28.3 9 Mar 09 Week 21 24 .2 12.9 41.1 21.8 11.8 33.6 20.6 9.7 31.2 16 Mar 09 Week 22 21.9 11.4 39.7 21.1 11.0 31.9 20.3 11.0 29.8 23 Mar 09 Week 23 21.7 11.0 35.3 21.3 11.0 33.6 20.7 10.6 31.4 30 Mar 09 Week 24 23.9 9.0 37.0 23.4 8.6 34.0 20.8 7.4 31.3

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58 Table 3 6 Effec ts of production systems and strawberry cultivars on chlorophyll content and plant canopy diameter at 8 and 12 weeks after transplanting (WAT). 2008 09 Season. Diameter Chlorophyll Content C m S PAD Value Production S ystems 8 WAT 12 WAT 8 WAT 12 WAT Tunnel 24 31 a 46.3 49.1 a Open field 23 28 b 48.4 48.0 b P value 0.1527 0.0018 0.0741 0.0174 Cultivars estival 26 a 35 a 45.2 b 46.4 c 23 b 27 b 48.5 a 48.7 b 22 b 27 c 48.5 a 50.6 a P value 0.0002 < 0.0001 0.0029 0.0004

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59 Table 3 7 Effects of production systems and strawberry cultivars on early yield and total yield. 2008 09 Season. Production S ystems Early yield T otal yield ( t /ha ) Tunnel 2.9 a 14.4 a Open field 2.5 b 9.6 b P va lue 0.0231 0.0030 Cultivars estival 3.3 a 18.6 a 2.7 b 9.0 b 2.0 c 8.4 b P value <0.0001 <0.0001

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60 Table 3 8 Effects of production systems and strawberry cultivars on yield 6 harvest s following a freeze or near freeze temperature event. 2008 09 Season. Date Jan uary 21 t o 23 Feb ruary 5 Feb ruary 21 Min imum Temp. ( O C) 3, 5.6 5 2.8 0.6 Production Systems Cultivars ----------------------t /ha ---------------------Tunnel 4.6 a 4.4 a 5.4 a Tunnel 3.0 bc 3.0 b 2.7 c Tunnel 2.4 c 2.6 b 2.7 cd Open Field 3.3 b 3.1 b 3.7 b Open Field 0.8 d 0.9 c 1.1 e Open Field 1.3 d 1.2 c 1.7 de P Value 0.0184 0.0267 0.0135

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61 F igure 3 1 Overview of strawberry field production in open field (top ) and in high tunnel (bottom ) on a freeze event. January 3, 2008, temperatur e dropped to 2.8 o C

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62 Figure 3 2 Effects of production system on strawberry skin color light ness o C in five different storage tests. 2007 08 Season

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63 Figure 3 3 Effects of production system on strawberry skin color light ness strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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64 Figure 3 4 Effects of production system on strawberry skin color light ness strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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65 Fig ure 3 5 Eff o C in five different storage tests. 2007 08 Season

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66 Figure 3 6 Effects of production syst strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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67 Figure 3 7 Effects of production system on strawberry skin color chr strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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68 Figure 3 8 Effects of production system on strawberry skin color hue angle Festiv o C in five different storage tests. 2007 08 Season

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69 Figure 3 9 Effects of production system on strawberry skin color hue angle strawberry before and af ter 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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70 Figure 3 10 Effects of production system on strawberry skin color hue angle strawberry before and after 8 days storage at 7. 2 o C in five different storage tests. 2007 08 Season

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71 Figure 3 11 strawberry before and after 8 days storage at 7.2 o C in five different storage t ests. 2007 08 Season

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72 Figure 3 12 before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season.

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7 3 Figure 3 13 before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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74 Figure 3 14 Effect strawberry after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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75 Figu re 3 15 Effects of production system on marketable fruit on 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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76 Figure 3 16 after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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77 Figure 3 17 Effects of production system on strawberry s oluble solids o C in five different storage tests. 2007 08. Season

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78 Figure 3 18 Effects of production system on strawberry s oluble solids strawberry before and after 8 days storage at 7.2 o C in five different storage tests 2007 08 Season

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79 Figure 3 19 Effects of production system on strawberry s oluble solids o C in five different storage tests. 2007 08 Season

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80 F igure 3 20 Effects of production system on strawberry total titratable o C in five different storage tests. 2007 08 Season

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81 Figure 3 21 Effects of production system on strawberry total titratable strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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82 Figure 3 22 Effects of production system on strawberry total titratable o C in five different storage tests. 2007 08 Season

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83 Figure 3 23 Effects of p r oduction system on strawberry v o C in five different storage tests. 2007 08 Season

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84 Figure 3 24 Effects of p roduction system on str awberry v strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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85 Figure 3 25 Effects of p roduction system on strawberry v strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season

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86 Figure 3 26 Effects of production system on strawberry skin color light ness before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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87 Figure 3 27 Effects of production system on strawberry skin color light ness strawberry before and after 8 days s torage at 7.2 o C in five different storage tests. 2008 09 Season

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88 Figure 3 28 Effects of production system on strawberry skin color light ness strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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89 Figure 3 29 o C in five different storage test s. 2008 09 Season

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90 Figure 3 30 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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91 Figure 3 31 strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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92 Figur e 3 32 Effects of production system on strawberry skin color hue angle o C in five different storage tests. 2008 09 Season

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93 Figure 3 33 Effects of p roduction system on strawberry skin color hue angle strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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94 Figure 3 34 Effects of production system on strawbe rry skin color hue angle strawberry before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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95 F igure 3 35 le fruit after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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96 Figure 3 36 storage at 7.2 o C in five different storage t ests. 2008 09 Season

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97 Figure 3 37 storage at 7.2 o C in five different storage tests. 2008 09 Season

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98 Figu re 3 38 oluble solids content before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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99 Figure 3 39 Effects of producti oluble solids content before and after 8 days storage at 7.2 o C in four different storage tests. 2008 09 Season

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100 Figure 3 40 erry s oluble solids content before and after 8 days storage at 7.2 o C in five different storage tests. 2008 09 Season

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101 C HAPTER 4 SUMMARY AND CONCLUSI ONS The use of high tunnels in Florida might have several benefits to growers, such as early production, wh ich might provide a competitive edge in the market. During the 2007 08 season, field for the the first five harvests. Considering a 5.5 kg strawberry tray, insi de the tunnels, there were 80 extra trays produced, and assuming a $30 per tray (average December price), additional $2,400 per hectare would be gross earned. Since high tunnels are protected structures, they could allow growing other crops or cultivars, w hich might be susceptible to rain or low temperatures. Flowers are protected from strawberry cultivar susceptible to cracking, performed well under tunnel cult ure. Direct field observations indicated that the protection given by high tunnels decreased the incidence of some diseases, such as anthracnose fruit rot, botrytis fruit rot, and bacterial angular leaf spot, resulting on decreased pesticide use. Higher st rawberry yield has been reported inside tunnels compared with open fields (Kader et al., 2006). Improvement of postharvest quality including higher soluble solids content, and higher vitamin C content in strawberry have been also reported (Voca et al., 200 7). High tunnels also have some limitation to be used in Florida, as mention above tunnels might protect plants from diseases, but also at the Research Center at Balm higher incidence of powdery mildew ( Sphaerotheca macularis ), two spotted spider mites ( Te tranychus urticae ) and chili thrips ( Scirtothrips dorsalis ) were found on the tunnels compared with the open field. Cost of installation and maintenance of high tunnels need to be considered, including the labor to install the structure and open and close the walls when the temperatures raise or drop, and also

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102 the opportunity of opening and closing of high tunnels might influence the results and need to be studied. The occurrence of hurricanes in Florida is another limitation to high tunnels use. A hurrican e can destroy the plastic or the whole tunnel structure, which means to replace the plastic or build a new tunnel for the following season with all the costs involved. Another barrier to the implementation of high tunnels in Florida is that conventional gr owers have been growing their crops, in this case strawberry following the same cultural practices for generations. In general growers are not willing to change a system that is well known for them. In synthesis, the results from the two experiments conduc ted at the Gulf Coast Research and Education Center in Balm were similar in some aspects and different in others.For both seasons, strawberry plants grown inside the high tunnel were equal or wider than plants in the open field. A cultivar effect was obser different on early yields and total yields. Strawberry yields inside the high tunnel were greater than yields in o marketable fruit percentage after storage production systems had significa awberry marketability after storage. Soluble presented higher values compared to fruit grown at open field. Some of the variables measured had different response depending of the season. For the 2007 08 season chlorophyll content was higher in open field compared to high tunnel. While, for

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103 the 2008 09 season, chlorophyll content was higher on high tunnel than open field. In the same way, cultivars affected signific antly chlorophyll content. However, in overall independently of the production system and the cultivar chlorophyll content were sufficient for the normal development of the strawberry crop. On the season 2007 08 the strawberry yield after freeze inside the 09 the interaction between factors had effects on strawberry yield after the three freezes occurred. the 2007 08 season lightness values were lower f or strawberry fruit before storage and higher after storage. However, for the 2008 09 season lightness values were higher for strawberry fruit before storage and lower after storage. This difference might be due to changes in handling of the fruit. For the 2007 08 season fruit was harvested in Balm at the Research Center, and transported to Gainesville to the Horticultural Department, to be processed next day. While, for 2008 09 season fruit was harvested and processed during the same morning at the Researc h Center in Balm. Chroma values in all the cultivars showed no difference when analyzed by production system, but in most cases values were higher before storage. Hue angle value did not present a clear trend effect for both production systems and cultivar s, and in most cases hue angle values before storage were lower than hue angle values after storage. In general, soluble solids content was higher on fruit from inside the high tunnels, soluble solids content value from both seasons the first season had lower soluble solids content than the second season, which might be due to a variation during the sample processing and

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104 preparation. Samples collected during the 2007 08 season were frozen, and stored until the end of the season. After that samples were defrosted, blended, centrifuged, filtered and evaluated for soluble solids content (Brix), while for the 2008 09 season, the fruit was harvest, cut and squeezed and ev aluated. Freezing the sample may a dilute it, if ice get inside the bag, centrifuge and filter might take some solids and as result the reading could be diminish. Postharvest data collected during the 2007 08 season, showed that production systems had no e ffects on firmness value for strawberry fruit before and after storage for the three cultivars. Firmness values were higher after storage, compared with the values before storage. This might be explained because the sampling method is destructive. Fruit is cut and destroyed to be measured. Moreover, a different fruit was measure after storage, and that fruit could be in a different maturity stage. Total titratable acidity was not affected by either of the production systems, but different cultivars presente d significant different acidity values on most of the sampling dates. The highest igher before storage than after storage. Again, this might be due to use of different fruit to measure acidity. Vitamin C content was affected by both, the production systems and the different cultivars. Fruit from inside the high tunnel had equal or highe r vitamin C content than fruit from open collected, strawberry fru it after storage have lower vitamin C than fruit before storage. With the information discussed above it is possible to conclude that the use of high tunnels, for environmental conditions present at the Research Center (Balm, Florida) or other

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105 surrounding locations, could help growers to increase plant diameter, improve early yields and total yields, and increase soluble solids content for some cultivars. Protected conditions could also allow the production of other crops or cultivar susceptible to low temp eratures or rain. High tunnels structures serve as frost protection, and as result the water saving can be up to 600,000 L/ha of water per night of low temperatures, considering both strawberry seasons in this study there were 6 nights with low temperature s (3,600,000 L/ha of water). High tunnels can improve water conservation and reduce energy costs. Further studies need to be conducted to determine more effects of the high tunnels on the postharvest quality of the fruit, the effects of the high tunnels on other cultivars and other crops, intercropping systems to optimize the use of the high tunnels, and also a detailed economical study to determine the feasibility of using this production system.

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106 APPENDIX A TEMPERATURE DATA FROM FAWN WEATH ER REPORT FOR BA LM, FLORIDA DURING 2007 08 AND 2008 09 SEASON S

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107 Table A 1. Daily average of d ata from FAWN weather report taken at 60 cm from soil for Balm during 2007 08 season. Date A verage M inimum M aximum ( o C) 15 Oct 07 24.0 18.0 31.4 16 Oct 07 24.9 19.2 31.1 17 Oct 07 25.7 19.7 33.8 18 Oct 07 26.3 21.1 33.3 19 Oct 07 26.0 20.9 32.4 20 Oct 07 24.1 21.8 26.9 21 Oct 07 25.4 22.4 31.4 22 Oct 07 27.2 24.2 33.1 23 Oct 07 26.5 22.3 32.7 24 Oct 07 22.4 20.4 24.2 25 Oct 07 20.8 17.8 23.7 26 Oct 07 22.2 17.8 28.2 27 Oct 07 23.8 22.1 27.2 28 Oct 07 24.1 20.6 29.4 29 Oct 07 23.4 21.0 27.0 30 Oct 07 22.8 20.7 26.3 31 Oct 07 24.8 22.2 29.6 1 Nov 07 24.6 22.1 29.2 2 Nov 07 22.8 16.9 29.3 3 Nov 07 18.7 11.4 25.4 4 Nov 07 17.7 9.3 27.3 5 N ov 07 17.5 10.0 25.8 6 Nov 07 18.2 11.5 27.1 7 Nov 07 16.0 10.9 23.5 8 Nov 07 14.9 7.3 23.9 9 Nov 07 15.3 7.8 23.8 10 Nov 07 15.3 5.6 25.5 11 Nov 07 17.3 8.8 26.2 12 Nov 07 19.1 13.5 27.4 13 Nov 07 20.4 14.9 28.3 14 Nov 07 20.3 14.0 28.3 15 Nov 0 7 19.5 11.8 27.0 16 Nov 07 11.2 4.7 18.4 17 Nov 07 14.1 4.8 25.0 18 Nov 07 17.6 9.0 26.7 19 Nov 07 19.7 14.3 27.1 20 Nov 07 20.2 14.3 27.9

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108 21 Nov 07 19.7 13.2 27.9 22 Nov 07 20.7 14.5 26.9 23 Nov 07 19.7 14.7 24.0 24 Nov 07 19.2 11.7 27.6 25 Nov 07 22.7 17.6 29.5 26 Nov 07 22.3 17.8 29.2 27 Nov 07 21.9 16.1 29.2 28 Nov 07 22.5 17.5 29.0 29 Nov 07 22.0 17.5 27.5 30 Nov 07 20.1 17.6 23.5 1 Dec 07 20.7 15.6 28.6 2 Dec 07 21.9 15.9 30.5 3 Dec 07 21.1 13.8 27.7 4 Dec 07 14.7 6.5 21.5 5 Dec 07 13.4 4.4 22.8 6 Dec 07 16.7 9.4 27.2 7 Dec 07 19.7 11.1 29.6 8 Dec 07 22.0 16.8 28.6 9 Dec 07 21.8 15.3 28.4 10 Dec 07 21.6 16.4 29.5 11 Dec 07 22.1 16.5 29.2 12 Dec 07 21.6 15.8 28.9 13 Dec 07 21.6 14.9 30.0 14 Dec 07 22.2 17.9 27.6 15 Dec 07 2 4.1 21.5 28.7 16 Dec 07 18.9 8.5 24.1 17 Dec 07 7.5 2.3 14.2 18 Dec 07 12.4 3.4 22.7 19 Dec 07 16.8 9.6 25.3 20 Dec 07 18.0 11.0 26.4 21 Dec 07 18.7 13.1 23.7 22 Dec 07 15.3 10.7 18.8 23 Dec 07 18.7 14.0 25.5 24 Dec 07 18.8 15.0 26.0 25 Dec 07 19 .1 14.1 26.9 26 Dec 07 17.0 12.8 23.6 27 Dec 07 19.2 12.0 28.7 28 Dec 07 21.6 15.7 29.0 29 Dec 07 21.4 16.5 28.9 30 Dec 07 22.5 16.9 28.2 31 Dec 07 21.9 17.4 26.4

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109 1 Jan 08 19.1 9.9 22.8 2 Jan 08 6.1 0.0 10.5 3 Jan 08 4.4 2.6 12.5 4 Jan 08 10.6 3 .2 19.6 5 Jan 08 15.0 8.4 23.3 6 Jan 08 18.0 13.0 26.3 7 Jan 08 19.6 13.0 27.1 8 Jan 08 19.7 14.0 27.7 9 Jan 08 18.3 9.5 27.8 10 Jan 08 19.4 13.9 28.0 11 Jan 08 19.4 12.1 27.3 12 Jan 08 20.5 13.7 28.7 13 Jan 08 20.7 14.7 27.1 14 Jan 08 13.6 7.2 1 8.7 15 Jan 08 10.5 2.9 18.8 16 Jan 08 16.3 8.6 23.6 17 Jan 08 20.4 17.1 24.0 18 Jan 08 17.7 16.3 19.2 19 Jan 08 20.4 15.8 27.3 20 Jan 08 10.4 6.1 15.3 21 Jan 08 13.5 4.6 23.0 22 Jan 08 19.9 13.1 27.3 23 Jan 08 20.8 16.3 26.4 24 Jan 08 17.5 13.5 2 1.8 25 Jan 08 13.6 7.0 20.2 26 Jan 08 15.2 8.2 22.0 27 Jan 08 15.8 9.3 20.5 28 Jan 08 11.3 4.0 20.7 29 Jan 08 14.0 2.7 24.3 30 Jan 08 19.5 14.0 26.6 31 Jan 08 19.7 11.9 27.8 1 Feb 08 18.1 9.5 24.8 2 Feb 08 16.9 5.8 29.0 3 Feb 08 19.8 11.9 28.5 4 Feb 08 20.9 14.7 29.5 5 Feb 08 20.5 14.2 29.7 6 Feb 08 21.3 13.8 27.8 7 Feb 08 22.7 18.4 28.9 8 Feb 08 20.7 16.2 25.7 9 Feb 08 17.7 13.1 21.6 10 Feb 08 16.0 7.8 23.9

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110 11 Feb 08 15.1 4.5 24.5 12 Feb 08 18.1 12.1 24.3 13 Feb 08 18.8 11.5 23.5 14 Fe b 08 11.9 3.7 21.4 15 Feb 08 16.3 7.7 25.9 16 Feb 08 18.7 11.2 27.4 17 Feb 08 21.2 14.4 29.3 18 Feb 08 21.7 16.3 28.6 19 Feb 08 16.3 9.8 22.5 20 Feb 08 15.2 6.7 22.1 21 Feb 08 20.4 14.5 27.5 22 Feb 08 23.0 18.8 29.2 23 Feb 08 22.0 18.8 27.7 24 Fe b 08 20.2 15.3 25.5 25 Feb 08 21.1 16.4 26.8 26 Feb 08 23.1 17.0 28.4 27 Feb 08 12.8 4.2 20.0 28 Feb 08 8.8 1.6 16.9 29 Feb 08 13.5 3.0 23.3 1 Mar 08 17.3 9.5 25.6 2 Mar 08 18.4 10.8 26.8 3 Mar 08 20.5 11.5 28.9 4 Mar 08 21.9 18.8 25.7 5 Mar 08 1 9.3 15.5 23.7 6 Mar 08 17.5 11.8 25.2 7 Mar 08 23.1 17.1 30.0 8 Mar 08 15.5 5.9 20.5 9 Mar 08 12.2 3.7 20.5 10 Mar 08 17.5 10.4 24.5 11 Mar 08 20.5 16.1 25.9 12 Mar 08 19.0 13.1 23.8 13 Mar 08 17.2 8.5 25.9 14 Mar 08 17.1 15.6 20.1 15 Mar 08 22.2 14.7 29.0 16 Mar 08 24.5 17.1 30.5 17 Mar 08 21.3 16.5 28.4 18 Mar 08 21.7 15.7 28.4 19 Mar 08 23.3 18.0 29.9 20 Mar 08 20.7 11.3 25.6 21 Mar 08 18.8 10.7 27.3 22 Mar 08 18.4 14.8 21.4

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111 23 Mar 08 21.6 16.6 28.0 24 Mar 08 16.7 10.0 21.7 25 Mar 08 12.8 4.0 21.0 26 Mar 08 16.1 8.5 24.5 27 Mar 08 18.6 9.4 27.6 28 Mar 08 13.5 13.5 13.5 Table A 2 Daily average of data from FAWN weather report taken at 60 cm from soil, for Balm during 2008 09 season. Date A verage M inimum M aximum ( o C) 15 Oct 08 2 4.0 17.7 31.0 16 Oct 08 23.2 17.8 31.0 17 Oct 08 23.4 16.6 32.2 18 Oct 08 22.9 16.1 29.7 19 Oct 08 20.0 13.3 27.5 20 Oct 08 21.1 15.4 29.2 21 Oct 08 21.7 16.0 29.3 22 Oct 08 22.8 17.0 28.8 23 Oct 08 24.0 21.0 28.5 24 Oct 08 23.5 20.7 27.6 25 Oct 08 23.8 18.8 28.4 26 Oct 08 19.4 13.0 27.2 27 Oct 08 18.8 10.7 27.6 28 Oct 08 12.0 6.0 18.1 29 Oct 08 11.0 1.6 20.1 30 Oct 08 14.6 5.0 24.0 31 Oct 08 18.3 12.3 26.3 1 Nov 08 18.4 13.8 25.5 2 Nov 08 19.4 17.4 25.7 3 Nov 08 21.0 17.0 28.0 4 Nov 08 18.2 16.5 20.2 5 Nov 08 17.7 16.0 19.4 6 Nov 08 19.1 12.7 27.5 7 Nov 08 19.8 12.0 29.1 8 Nov 08 19.9 12.4 27.3 9 Nov 08 17.1 10.0 25.4 10 Nov 08 16.4 8.2 25.6 11 Nov 08 19.3 11.5 28.2 12 Nov 08 23.3 17.6 30.7 13 Nov 08 25.1 20.6 31.9

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112 14 Nov 08 24 .5 19.7 32.2 15 Nov 08 22.7 17.9 27.6 16 Nov 08 12.4 3.2 17.9 17 Nov 08 11.0 2.6 20.3 18 Nov 08 13.3 6.8 21.9 19 Nov 08 9.4 2.2 18.6 20 Nov 08 10.9 0.8 21.4 21 Nov 08 14.1 6.1 23.8 22 Nov 08 11.8 4.5 21.2 23 Nov 08 13.9 7.4 23.2 24 Nov 08 16.1 9. 6 25.6 25 Nov 08 15.0 7.8 23.9 26 Nov 08 12.4 2.8 23.0 27 Nov 08 11.1 0.6 23.4 28 Nov 08 13.4 3.3 26.3 29 Nov 08 17.3 6.4 27.4 30 Nov 08 18.6 15.2 25.2 1 Dec 08 16.5 11.9 20.6 2 Dec 08 11.7 2.1 17.0 3 Dec 08 11.0 1.3 21.7 4 Dec 08 16.2 8.8 26.0 5 Dec 08 16.7 8.1 26.5 6 Dec 08 17.2 9.3 24.4 7 Dec 08 14.2 6.2 19.9 8 Dec 08 13.4 3.0 24.5 9 Dec 08 19.3 10.3 28.1 10 Dec 08 22.5 18.8 29.4 11 Dec 08 19.9 16.5 22.3 12 Dec 08 14.4 8.2 18.3 13 Dec 08 11.7 3.0 20.4 14 Dec 08 17.8 10.9 25.5 15 Dec 08 20.2 17.8 25.1 16 Dec 08 19.9 13.6 27.4 17 Dec 08 20.5 14.6 27.6 18 Dec 08 20.2 14.7 27.6 19 Dec 08 18.7 12.5 27.5 20 Dec 08 16.7 11.0 25.2 21 Dec 08 17.5 9.6 26.1 22 Dec 08 12.6 6.7 17.3 23 Dec 08 15.1 6.1 24.8 24 Dec 08 21.6 15.2 28.2

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113 25 Dec 08 22.7 20.1 27.5 26 Dec 08 21.9 17.1 28.7 27 Dec 08 20.2 14.4 27.7 28 Dec 08 19.9 13.2 28.1 29 Dec 08 19.4 12.4 26.9 30 Dec 08 18.0 7.4 26.0 31 Dec 08 15.0 5.4 24.2 1 Jan 09 15.3 8.4 22.9 2 Jan 09 17.9 12.8 26.3 3 Jan 09 18.1 11.1 26.0 4 Jan 09 19.5 13.1 27.5 5 Jan 09 19.7 13.8 29.3 6 Jan 09 20.2 12.7 28.7 7 Jan 09 18.1 6.8 24.9 8 Jan 09 13.3 4.0 22.1 9 Jan 09 13.7 6.3 24.1 10 Jan 09 15.8 7.5 26.7 11 Jan 09 17.6 9.5 26.2 12 Jan 09 17.7 15.2 20.8 13 Jan 09 15.7 10.3 25.9 14 Jan 09 11.2 1.7 21.2 15 Jan 09 8.5 2.3 15.4 16 Jan 09 10.0 4.7 17.5 17 Jan 09 9.3 1.6 19.0 18 Jan 09 12.3 2.6 22.6 19 Jan 09 16.7 10.0 20.8 20 Jan 09 11.3 5.1 17.6 21 Jan 09 4.2 3.3 11.1 22 Jan 09 5.5 4.7 18.1 23 Jan 09 9.8 2.1 23.0 24 Jan 09 12.7 2.4 22. 7 25 Jan 09 15.5 5.6 26.3 26 Jan 09 18.2 9.0 27.5 27 Jan 09 20.2 13.2 28.2 28 Jan 09 21.4 16.8 28.6 29 Jan 09 21.0 16.7 27.1 30 Jan 09 14.1 8.8 18.8 31 Jan 09 8.9 1.7 17.6 1 Feb 09 11.8 1.4 21.3 2 Feb 09 16.0 11.8 19.4 3 Feb 09 12.2 3.0 15.8

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114 4 F eb 09 7.4 1.1 13.6 5 Feb 09 3.8 2.7 12.6 6 Feb 09 8.7 1.4 20.3 7 Feb 09 12.7 4.6 22.6 8 Feb 09 14.8 6.7 24.4 9 Feb 09 15.5 5.4 25.4 10 Feb 09 17.5 9.0 27.6 11 Feb 09 20.3 11.9 29.2 12 Feb 09 20.4 16.6 26.8 13 Feb 09 19.9 12.8 29.8 14 Feb 09 17. 3 9.8 24.9 15 Feb 09 20.2 15.8 26.7 16 Feb 09 18.4 8.9 24.3 17 Feb 09 14.1 5.6 24.1 18 Feb 09 17.0 7.5 24.9 19 Feb 09 18.1 15.1 24.3 20 Feb 09 12.5 3.2 18.7 21 Feb 09 12.0 0.2 24.5 22 Feb 09 16.3 7.7 24.7 23 Feb 09 15.4 8.7 23.6 24 Feb 09 14.5 5 .0 24.8 25 Feb 09 17.0 9.9 25.6 26 Feb 09 17.0 8.6 25.9 27 Feb 09 18.0 9.8 28.4 28 Feb 09 19.0 9.8 28.6 1 Mar 09 15.0 10.1 20.1 2 Mar 09 10.0 2.4 14.8 3 Mar 09 9.5 1.0 19.2 4 Mar 09 12.6 3.1 23.2 5 Mar 09 16.2 7.4 25.1 6 Mar 09 17.4 7.9 27.0 7 M ar 09 17.9 8.1 28.5 8 Mar 09 18.8 8.8 28.5 9 Mar 09 19.4 9.8 28.7 10 Mar 09 19.8 10.1 30.9 11 Mar 09 20.3 10.0 31.5 12 Mar 09 20.1 11.0 29.9 13 Mar 09 21.6 14.5 29.2 14 Mar 09 21.9 15.4 30.5 15 Mar 09 22.5 15.9 30.9 16 Mar 09 22.2 15.0 30.0

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115 17 Ma r 09 20.6 14.7 26.8 18 Mar 09 21.6 16.6 28.8 19 Mar 09 21.1 15.2 28.8 20 Mar 09 20.2 11.2 28.8 21 Mar 09 19.6 13.2 27.9 22 Mar 09 17.7 11.1 25.1 23 Mar 09 17.1 14.0 21.0 24 Mar 09 19.3 10.7 27.9 25 Mar 09 20.1 11.0 28.5 26 Mar 09 21.6 14.7 29.8 2 7 Mar 09 22.3 16.1 30.2 28 Mar 09 25.2 20.6 31.7 29 Mar 09 20.5 11.2 24.5 30 Mar 09 18.7 7.4 30.1

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116 APPENDIX B EFFECTS OF PRODUCTIO N SYSTEM ON STRAWBER RY PH ON STRAWBERRY FRUITS BEFORE AND AF TER 8 DAYS STORAGE A T 7.2 O C IN FIVE DI FFERENT STORAGE TESTS ON 2007 08 S EASON

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117 F igure B 1 before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season.

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118 Figure B and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season.

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119 Figure B 3 Effects of product before and after 8 days storage at 7.2 o C in five different storage tests. 2007 08 Season.

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120 LIST OF REFERENCES Bakker, J.C. 1991. Analysis of humidity effects on growth and production of glasshouse fruit vegetables. Dissertation Agicultural University Wageningen 155 pp. Blomgren, T. and T. Frisch. 2007. High tunnels. Using low cost technology to increase yields, improve quality and extend the season. University of Vermont Center for Sustainable Agri culture. Last accessed 16 July 2009. < http://www.uvm.edu/sustainableagriculture/hightunnels.html > Burgess, C.M. 1997. Nutrition of new everbearing strawberry cultivars. Acta Hort. (ISHS) 439:693 700. Callies, T. 2008. Safeguarding Strawberries. Florida Grower. Vol. 101:28 30. Chandler, C .K. and A. Whidden. 2007. Strawberry Cultivar Situation in West Central Florida. Berry/ Vegetable Time. University of Florida, IFAS Extension. Chand ler, C.K., B.M. Santos, N.A. Peres A. Plotto, C. Jouquand, and C.A. Sims In p ress ) Chandler, C.K. and D.E. Legard. 2003. Strawberry Cultivar s for Annual Production, p 19 25. In N.F.Childers (ed.). The St rawberry. A book for growers, others. Institute of Food and Agricultural Sciences, Horticultural Sciences Department, University of Florida, Gainesville, FL. Childers, N. 1980. The strawberry: cultivars to marketing. Horticultural Publications, Gainesville FL. 514 pp. Childers, N. 2003. The Strawberry. A book for growers, others. Institute of Food and Agricultural Sciences, Horticultural Sciences Department, University of Florida, Gainesville, FL. Chism, J. 2002. Warm Season vegetable production in high t unnels. Future Farms 2002: A Supermarket of Ideas. Last accessed 16 June 2009 < http://www.kerrcenter.com/publications/2002_proceedings/warm season_veggies.pdf > Cordenunsi, B.R., J.R. Nascimento, and F.M. Lajolo. 2003. Physico chemical changes related to quality of five strawberry fruit cultivars during cool storage. Food Chemistry 83:167 173. Crocker, T.E. and C.K. Chandler. 2000. Strawberry cultivar update. Last accessed 16 June 2009. < http://strawberry.ifas.ufl.edu/Agritech/agritech00cultivars.htm > Dana, M.N. 1980. The Strawber ry Plant and its Environment, p .32 34. In N.F. Childers (e d .). The Strawberry: Cultivars Marketing. Hort icultural Publ ication, Gainesville, FL. Darnell, R. 2003. St rawberry Growth and Development, p. 3 10. In N.F.Childers (ed.). The Strawberry. A book for growers, others. Institute of Food and Agricultural Scienc es, Horticultural Sciences Department, University of Florida, Gainesville, FL.

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121 Darrow, G.M. 1966. The Strawberry: History, Breeding and Physiology. Holt, Rinehart and Winston, New York, NY. Last accessed 16 June 2009. < http://www.nal.usda.gov/pgdic/Strawberry/darpubs.htm > Davis, T. 2008. An Introduction of Strawberries. University of New Hampshire, Durham, NH. 16 June 2009. < http://str awberrygenes.unh.edu/history.html > Demchak, K. 2004. Plasticulture Strawberries in Northern Climates. Great Lakes Fruit, Vegetable & Farm Market Expo Grand Rapids, MI. December 7 9, 2004. Last accessed 16 June 2009. < http://www.glexpo.com/abstracts/2004abstracts/plasticulture.pdf > Fletcher, S.W. 1917. The Strawberry in North America, History, Origin, B otany and Breeding. Macmillan, New York 232pp. Flo rida Automated Weather Netw ork (FAWN). 2009. Florida Automated Weather Network database. Last accessed 16 June 2009. < http://fawn.ifas.ufl.edu/>. Florida Foundation Seed Producers (FFSP). 2008. Strawberry Cultivars. Last accessed 16 June 2 009. < http://ffsp.net/strawberry.html > Food and Agricultural Organization. 2008. FAOSTAT. Last accessed 16 June 2009. < http ://faostat.fao.org/site/567/DesktopDefault.aspx?PageID=567#ancor > Galletta, G.J. and R.S. Bringhurst. 1990. Strawberry Management, p .83 156. In G.J. Galletta and D.G. Himelrick (eds.) Small Fruit Crop Management. Prentice Hall, Englewood Cliffs, New Jerse y. Gunness P. O. Kravchukb, S M. Nottinghamc, B and M J. Gidleya 2009. Sensory analysis of individual strawberry fruit and comparison with instrumental analysis Postharvest B iology and Technology 52: 164 172 Handley, D. T. 2003. The Strawber ry Plant: What You Should Know. University of Maine Cooperative Extension. Monmouth, Maine. Last accessed 15 December 2008. < http://www.newenglandvf c.org/sessions_03/strawberry2/strawberry_plant_what_you_should_k now.pdf > High Tunnel Vegetable and Small Fruit Production Team (HTVSFPT). 2003. Vegetable Production in High Tunnels: An Overview Dept. of Horticulture, Penn State University. Last accessed 1 6 June 2009. < http://plasticulture.cas.psu.edu/pdf/ht_1 8.pdf > Himelrick, D.G., C.W. Wood and W.A. Dozier Jr. 1992. Relationship between SPAD 502 meter values and extractable chlorophyll in str awberry. Advances in Strawberry Research 11:59 61. Jett, L.W. 2007. Growing strawberries in high tunnels in Missouri. University of Missouri, Columbia. Last accessed 20 June 2008. < http://www.hightunnels.org/PDF/Growing_Strawberries_in_High_Tunnels.pdf >

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122 Kader, A.A.1996. Maturity, ripening, and quality relationship of fruit vegetables. Acta Hort. 434:249 255. Kader, A.A. 2000. Quality of horticultural products. Acta Hort. 5 17:17 18. Kader, A.A. 2002. Postharvest technology of horticultural crops. UC Publication 3311. University of California, Division of Agriculture and Natural Resources, Oakland, California. 535 pp. Kadir, S., E. Carey, and S. Ennahli. 2006. Influence of hi gh tunnel and field conditions on strawberry growth and development. HortScience 41:329 335. Klonsky, K.M. and R.L. De Moura, 2001. Sample costs to produces strawberries. South Coast Region Ventura County UC Cooperative Extension. Last accessed 20 Ju ne 2008. < http://cesantacruz.ucdavis.edu/files/12721.pdf > Lamont, W. 2009. Overview of the use of high tunnels worldwide. Hort T echnology 19(1):25 29. Lee, S.K. and A.A. Kader. 2000. Preharvest an d postharvest factors influencing vitamin C content of horticultural crops. Postharvest Biology and Technology 20:207 220. Lopez Aranda, J.M. 2008. Fisiologa y anatoma de la planta de frutilla. Morfo anatoma Curso: El Cultivo de la Frutilla, Avances Te cnolgicos Pontificia Universidad Catlica de Chile, Facultad de Agronoma e Ingeniera Forestal, Santiago de Chile. 30 Junio 3 Julio 2008. Lutchoomun, S. and C.L. Cangy. 1997. Comparison of production systems and varietal evaluation of strawbe rry. Curep ipe Agricultural Resear ch Station Unit. Last accessed 18 March 2009.< http://www.gov.mu/portal/sites/ncb/moa/farc/amas97/html/p23.htm >. McGuire, R.G. 1992. Reporting of objective color measurements. HortScience 27(12):1254 1255. Montero, J.I., N. Castilla, E Gutierrez de Rave, and P. Bretones. 1985. Climate under plastic in Almeria area. Acta Hort (ISHS) 170:227 234. Montri, A. and J.A. Biernbaum. 2009. Management of the soil env ironment in high tunnels. HortTechnology 19(1):34 36. North American Strawberry Growers Association. 1982. Advances in strawberry research. Volume I. Springer, Netherlands Nunes, M.C.N, A.M.M.B. Morais, J.K. Brecht and S.A. Sargent. 2002. Fruit maturity and storage temperature influence response of strawberries to controlled atmospheres. J. Amer. Soc. Hort. Sci. 127:836 842. Nunes, M.C.N., J.P. Edmond, and J.K. Brecht. 2003. Quality of strawberries as affected by temperature abuse during ground, in fligh t and retail handling operations. Acta Hort. 604:239 246.

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125 BIOGRAPHICAL SKETCH Teresa P. Salam Donoso is or iginally from Santiago Chile. She pursued a Bachelor of Science in Agriculture at the Pontificia Universidad Catolica de Chile with a minor in Fruit Production, and graduated from it in the year 2001. From 2001 to 2003, she worked at the Southwest Florida Research and Education Center (Immokalee, FL) as a research assistant on production, uses and benefits of compost in agriculture. Teresa then returned to Chile and worked from 2004 to 2006 in the Country Service Program ("Servicio Pais") in the town of Me lipeuco, IX Region, performing extension work with small farmers in sustainable agriculture. From 2006 to 2007 she worked at the Southwest Florida Research and Education Center (Immokalee, FL), conducting research on Best Management Practices (BMP) for Nit rogen and Phosphorus fertilization for vegetables on Florida. As a m aster s student she worked in Dr. Bielinski Santos horticultural program at the Gu lf Coast Research and Education Center (Balm, FL), in the Horticultural Sciences Department at the Univers ity of Florida. During her years at UF, Teresa was also the Horticultural Sciences Department Representative Student to the Graduate Student Council and Secretary of Social Affairs of the Hispanic Graduate Student Association.