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Everglades Station Mimeo Report 60-5 POPCORN TESTS EVERGLADES AREA 1952 1959 by Victor E. Green, Jr. and Emmett D. Harris, Jr. i This report contains results of research with popcorn grown on organic soils in south Florida and supercedes Mimeo 59-10, 58-4 and 57-4, which can be discarded. The work was conducted in cooperation with the Ames Seed Farms of Ames, Iowa and the Central Popcorn Company of Schaller, Iowa, who furnished seed and determined expansion ratios and quality. Agronomic Evaluation To date, the agronomic research on popcorn in the Everglades area has consisted chiefly of screening released and experimental hybrids. Tests were begun in 1952 and are continuing. Poor yielding and disease susceptible varieties are discarded each year and are replaced by other varieties. The tests have had the following characteristics in the various years: 1952 1953 1954 1955 1956 1957 1958 No. of Varieties Date of Planting Dates of Harvest Width between rows, ft. Drill Spacing-Plants/Hill Population, thousands/acre Row Length, Ft. Rows per plot Harvested Area, Rows Replications, Number Design, Randomized Com- plete Block Insect Control Leaf Blight Control Three-foot rows used each year 2-15" 1-12" each year thereafter 19.3 14.5 each year thereafter 50 50 50 40 89 25 50 50 3 6 3 3 1 1 1 1 1 6 3 1 1 1 1 1 4 4 3 4 each year thereafter R.C.B. Latin R.C.B. each year thereafter square 3 sprayings/crop .of 1 quart 25% DDT emulsion per acre None in any year Each year wireworms were controlled by applying 3 to 5 pounds of technical aldrin or heptachlor per acre into the soil by spraying and immediately disking. An- nually, the crop was planted and thinned by hand, and skips in the stand were replanted soon to insure a perfect stand. Cultivations numbered three per crop at about two-week intervals after germination. Soil was thrown to the rows to help reduce root lodging. '? V/ Victor E. Green, Jr., Associate Agronomist and Emmett D. Harris, Jr.,-,: Assistant Entomologist, Everglades Experiment Station, Belle Gladei,' < 5 -2 Fl orida. \'3 f. \95 4 1/28 5/28 6 3/6 6/16 to 7/3 12 2/1 5/21 to 6/9 1959 19 1/30 6/7 15 1/28 6/6 to 6/20 21 2/7 6/5 and 6/18 18 2/26 6/16/ 23 2/17 6/10 16 September 1959 Stalk and ear heights were measured following anthesis. About two weeks after anthesis, reaction to northern leaf blight caused by Helminthosporium turcicum Pass. was determined. No blight readings were made in 1952. In 1953, they were made by W. N. Stoner, then Assistant Plant Pathologist, Everglades Station: in 1954 and 1959 by the senior author, and in 1955 to 1958 by Miss Alice Robert of the Crops Research Division, U.S.D.A. As the varieties ripened, they were picked, husked and weighed. Samples were taken for moisture determination, weight-per-bushel test, and for popping. The latter two tests were performed by the Central Popcorn Company for the 1952- 1957 crops and by the Ames Seed Farms in 1958 and 1959. Yields were calculated at 15.5 percent moisture on an acre basis. Shelling percentages were calculated in 1955 and 1956. In 1952 the test was merely observational and was carried out to check whether any of the varieties from Iowa were adaptable to the south Florida environment. The March 6 planting yielded marketable popcorn, but the April 1 planting was a complete failure. All corn usually fails when planted late in this area. Table 1 shows the 1952 yields and harvest dates. Table 1. The Characteristics and Performance of Six Popcorn Varieties at Belle Glade, Florida, 1952. Central Hybrid Number Yield, Ibs./A at 15.59 Moisture 1 1930 7--2-52 2 1745 7-2-52 3 2065 7-3-52 4 1860 7-3-52 5 585 6-16-52 6 325 7-3-52 1_ Planted March 6, 1952 In 1953, four improved varieties were received from the Central Popcorn Company. They were numbered according to days required to approximate maturity near Schaller, Iowa. The data collected during 1953 are shown in Table 2. Table 2. The Characteristics and Performance of Four Popcorn Varieties at Belle Glade, Florida, 1953. Variety Yields, lbs/A Disease Stalk Off. Normal Moisture at 15.5% Index L/ Ht.,Ft. Volume Expansion, at Harvest, 2/ Moisture Test Volumes C-105 1985 0.5 6 27 32 21.97 C-110 2600 2.0 8 29 33 18.82 0-112 2780 4.0 8 33 35 24.46 C-115 3330 3.0 8 35 35 26.06 Scale 0-5 L.S.D. for yields: .05 : 505 lbs.; .01 = 765 lbs. I/ Readings on April 23. Higher numbers indicate more injury. 2/ Planted January 28, 1953. Harvested May 28, 1953. nRtp h4 namtpat L/ The variety C-115, the latest maturing variety, yielded better than the earlier varieties, even though resistance to Helminthosporium leaf blight was greater in two of the other three. On lots of seed that were dried, shelled and equalized for prime moisture content, the popping volumes of Florida grown material were two to four volumes lower than Iowa grown corn. This was the first indication that the later varieties might give the highest yields and the best popping quality in south Florida. The shortness of the stalks suggested the possibility of combining the grain. Hybrid 110 had considerable weevil infestation, but the other hybrids were free from insect damage. The ears of 115 were normal in size, while those of the earlier varieties were much shorter than normal. In 1954, the five best 1952 varieties, the 1953 varieties, Purdue 31 and 32, and Japanese Hulless (Improved Baby Rice) were grown. 1954 was a bad blight year and some of the varieties had dry leaves when the grain was in the milk stage. Stalk heights did not exceed seven feet and ears were no more than three and one half feet from the soil surface. With such low ear formation, weed control assumes major importance. Expansion of the kernels was reduced by 2.5 to 8 volumes by leaf blight. The variety Central Hybrid 1 was the highest yielding variety, 2990 pounds per acre. Central 4 rated second. Both these varieties had the highest popping volumes. See Table 3. In 1955, Central Hybrids 1, 2 and 4 were planted again along with ten new released from Iowa, the variety South American and the inbred YS(RS)F11 from the Cuba Agricultural Experiment Station. The year was very good from the standpoint of corn production. Blight readings were not taken until three weeks before har- vest. Good yields were received from all varieties except South American. Stalk heights of the corn belt popcorns varied from 5.4 feet to 6.8 feet and all varie- ties seemed well suited to combine harvesting if care is taken not to break the hull of the grains. The Cuban variety averaged 8.8 feet in height and possessed the most resistance to leaf blight. It yielded 3670 pounds per acre. However, it had the lowest shelling percentage and popping volumes of Florida grown corn were higher than the normal expansion figures for all varieties. Shelling per- centages of the Central varieties were between 76.7 and 82.5, and the Cuban variety, due to a large cob, yielded about 72 percent grain. Central Hybrid 4 was the earliest maturing variety as reflected by the moisture content at harvest. In 1956, 19 varieties of popcorn were grown. These included the best varieties from former years along with additional crosses from the Central Popcorn Company. Central Hybrid No. 1 gave the highest yield of grain again for the third year. The characteristics and performance of the varieties are shown in Table 5. In 1957, northern leaf blight assumed epiphytotic porportions. This factor along with an extremely high rainfall during the early growth of the plants caused severe stunting and reduced yields. The three highest yielding entries were experimental varieties 7-303, 7-336 and 7-310 from the Central Popcorn Company. However, the varieties scoring less than 3.0 for blight were Purdue 202 and Central Hybrid No. 1. The tallest stalks did not produce the highest yields. Nor were high yields related to the length of the growing season. The agronomic and industrial characteristics of the popcorns grown in 1957 are shown in Table 6. Table 3.-- The Characteristics and Performance of 12 Popcorn Varieties at Belle Glade, Florida, 1954. Height,Ft. Stalk Ear 6.0 5.5 7.0 6.5 6.5 7.0 6.0 7.0 6.0 7.0 6.0 6.5 3.0 2.5 3.5 3.5 3.5 3.5 2.5 3.0 2.5 3.0 2.5 3.0 Weight/ bushel Ibs. 65.5 63.0 65.0 65.5 62.0 64.0 61.0 63.5 61.5 61.0 59.5 63.0 Off. Volume Test Normal Expansion Volumes 32.5 33.5 31.5 31.0 26.0 29.0 26.0 30.0 30.0 30.0 21.5 30.5 L.S.D. for yields: .05 = 750 Ibs.; .01 : 1000 Ibs. C : Central Popcorn hybrid; P : Purdue Hybrid 2/ Readings on April 26. Higher numbers indicate more injury. Planted February 1, 1954. Table 4.--The Characteristics and Performance of 15 Popcorn Varieties at Belle Glade, Florida. 1955. Variety I/ Yields lbs/A 15.5% Disease Index 2/ Height,Ft. Stalk Ear Weight/ Bushel lbs. Off. Volume Test Normal Expansion Volumes 1 c-i Hy. 4610 8 0-5-319 4260 5 0-5423 3670 15 YS(RS)F11 3670 6 C-5-428 3430 12 C-5-343 3110 2 C-4 Hy. 2990 3 C-5-404 2990 4 0-5-409 2920 13 C-2 HY 2750 7 C-5-436 2650 10 C-5-331 2640 9 0-5-330 2370 11 C-5-332 2330 14 South 1060 American 3.4 4.0 4.0 3.0 3.6 4.5 4.5 4.1 3.8 3.6 4.5 4.8 5.0 4.9 4.9 6.8 6.3 6.0 8.8 5.8 6.0 5.4 6.0 6.0 7.0 5.9 5.9 6.0 5.8 6.3 3.6 3.3 3.0 5.1 2.9 3.0 2.8 2.8 2.9 3.6 3.0 3.0 2.8 3.0 3.3 65.5 66.5 63.5 64.0 65.0 65.5 66.5 65.0 65.5 63.0 65.5 66.0 63.5 63.5 62.0 37.5 40.o 38.0 23.0 38.0 39.0 39.0 40.0 39.0 36.0 37.5 40o.o 37.5 40.0 31.5 31.14 28.59 23.57 34.40 24.17 28.59 21.20 25.77 29.61 32.77 23.72 23.57 24.33 28.59 23.72 S.D. for Yields: .05 e 1280 Ibs.; .01 = 1710 Ibs. C Central Popcorn Company; YS(RS) F11 is an open-pollinated variety from the Cuba Agri. Expt. Station. Readings on May 16. Higher numbers indicate more injury. Planted Jan. 28, 1955. Harvested June 6, 1955. High moisture indicates lateness. YS(RS)F11 he.rvested June 20. Variety V C-1 c-4 P-32 C-2 C-3 c-115 0-105 P-31 C-5 C-110 Jap. H. C-112 Yields Ibs/A 15.5% 2990 2270 2200 2080 2020 1980 1670 16co 148o 1380 980 950 Date of Harvest 6- 8-54 5-25-54 6- 9-54 6- 8-54 6- 8-54 6- 9-54 5-21-54 6- 8-54 5-25-54 5-25-54 5-21-54 6- 2-54 Disease Index 2/ 2.0 2.5 2.0 3.0 2.5 2.5 3.0 2.0 3.0 4.0 2.5 4.0 Moisture at Harvest 4 L. V __ Table 5. The Characteristics and Performance of 19 Popcorn Varieties at Belle Glade, Florida. 1956. Variety i/ Yields Ibs./A @ 15.5% Disease Index 2/ Height, Ft. Wt./Bu. Stalk Ear lbs. Off. Volume Test Normal Expansion, Volumes * Pulling Percent- age Times Grown, yrs. Yield, Av. Ibs./A @ 15.5% C-1-HY C-6-329 P-31 C-5-401 P-32 C-2-HY C-55 C-6-343 C-115 C-5-HY P-202 c-6-417 C-4-lHY C-6-3o3c YS(RS)FU1 C-6-412 c-6-337 c-6-312 C-105 No Significant Difference between Yields 1/C Central Popcorn Company. YS(RS)F1 is an open-pollinated variety from the Cuba Agr. Exp. STa. 2/ Readings by Miss Alice Robert, FCRB,ARS,USDA on May 15, 1956. Scale 0-5. 0 no injury. P Purdue Hybrid Planted January 30, 1956. Harvested June 7, 1956. 3085 2750 2560 2550 2515 2500 2435 2370 2370 2345 2335 2325 2255 2140 2125 2065 1720 1450 1365 1.9 2.1 2.1 2.6 2.3 2.5 2.3 2.7 2.1 3.1 1.4 2.5 3.0 2.1 1.9 2.8 2.3 1.6 3.3 6.0 6.3 6.5 5.9 6.5 6.5 5.6 6.8 6.5 6.0 5.1 5.9 5.3 6.0 6.4 5.6 6.1 6.1 5.5 3.3 3.1 3.0 2.9 2.6 3.3 2.8 3.6 3.5 2.4 2.9 3.1 2.8 2.8 3.5 2.6 3.0 2.9 2.4 65.7 67.0 66.o 67.0 66.0 66.7 65.0 66.0 66.3 65.3 66.0 66.0 65.3 66.0 64.5 65.0 66.3 65.6 62.7 36.0 35.0 34.0 37.0 34.0 32.0 34.0 36.5 33.0 40.0 38.0 38.0 38.0 35.0 33.0 37.5 37.5 33.0 34.5 84.1 81.8 82.4 80.6 82.8 80.3 81.5 82.3 83.3 82.3 78.5 80.9 79.2 82.1 76.7 85.1 83.6 77.9 76.8 3155 2080 2360 2270 2560 1470 2345 2900 1675 ._ __ Table 6. The Characteristics and Performance of 21 Popcorn Varieties at Belle Glade, Florida. 1957 Variety I/ Yields, Ibs./A @ 15.5% V/ Disease Index 3/ Height,Ft. Wt./Bu. Stalk Ear Ibs. Off. Volume Test Normal Expansion, Volumes C-7-303 C-7-336 C-7-310 C-7-389 C-1-HY P-31 C-7-419 c-4-HY P-32 C-7-374 C-7-369 YS(RS)FlU c-6-408 C-7-313 Gattoni C-7-300 C-115 C-7-432 C-7-424 P-202 C-7-306 3120 2735 2555 2080 1950 1950 1730 1615 1540 1465 1405 1395 1385 1380 1280 1250 1200 1075 lo4o 985 850 3.5 3.0 3.8 3.8 2.9 3.3 3.9 4.0 3.1 3.0 3.8 3.3 4.4 3.3 3.0 4.3 3.3 3.6 3.0 2.5 3.3 5.5 6.5 5.5 6.0 5.0 5.5 5.0 4.5 5.5 6.5 5.5 5.0 5.0 6.0 8.0 4.5 5.0 5.5 5.0 4.0 5.5 3.0 3.5 2.5 3.0 3.0 2.5 2.5 2.0 2.5 3.0 3.0 2.0 2.0 3.0 4.5 2.0 2.5 3.0 2.5 2.0 3.0 30.0 35.0 29.0 31.5 34.0 24.0 32.0 31.5 24.0 28.5 30.5 33.0 30.5 35.0 10.0 31.0 29.0 30.5 29.0 27.0 33.0 84.1 82.4 82.8 76.7 83.3 78.5 18.98 26.00 17.34 20.00 18.37 19.34 19.34 17.84 20.00 22.67 16.33 17.58 17.94 22.67 16.84 16.62 29.00 22.67 18.64 15.55 18.64 2915 2035 2200 2085 3 2395 4 2220 2 1660 LSD .05 : 665 Ibs.; LSD .01 = 885 Ibs. / C Central Popcorn Company; P Purdue Hybrid. Gattoni is an open-pollinated variety from Panama and YS(RS)FUI is from Cuba. / Yields joined by the same line are not significantly different; others are. / Readings by Miss Alice L. Robert, CRD-ARS-USDA. Scale 0-5. 0 No injury. May 8, 1957. Planted February 7, 1957. Harvested June 5, 1957. Gattoni Harvested June 18, 1957. Shelling Percent- age S Moisture at Harve st Times Grown Yrs. Av.Yield lbs./A @ 15.5% In 1958, seven varieties were repeated along with eleven popcorns that had not been tested before in this area. Yields generally were low in 1958, and are attributable to poor growth of the plants during their early life brought about by low air and soil temperatures and abnormal plant nutrition. The highest yielding varieties were, along with the best three in 1957--C7-303(ASF5'-.3435), C7-310 (ASF54-3437) and C7-336(ASF92-3454), the newly tried varieties-Iowa 4258, ASF A-81, ASF 38-2874, and ASF 2894-3856. Yields were not related to incidence of Northern Leaf Blight. Good resis- tance to blight was displayed by Purdue 202, Iowa 4258, Nebraska 104 and ASF 2894- A34, all of which had readings below 2.0. An ear corn quality index was used in 1958 to define the overall appearance of the ears. Grades range from 10.0 for perfect ears down to 1.0 for very poor ears. The above data plus weight per bushel determinations, popping quality, and average yields of the older varieties are shown in Table 7. The official volume test data are compared with the new weight volume test method. The new method gives an index figure for calculating expansions by measuring the cubic inches of popped corn from 150 grams of raw popcorn and calculating cubic inches per pound of raw popcorn. On 18 samples, there was a very close correlation between the two test methods. The correlation coefficient was 4 0.971, which was highly significant. At the one percent level, a value of only 0.575 was required for significance. In 1959, a test of 23 varieties was grown. Eight varieties were repeated from the 1958.test, six of which were high yielding and two of which had given fair yields over a four-year period. Seed of Iowa 4258 and ASF 92-3454 (C-7-336) were not obtained for the 1959 test. Fifteen varieties were tested for the first time. They represented new, improved crosses for yielding ability, resistance to leaf blights and for quality. Sulfur was added to the soil and thoroughly mixed therein to reduce the soil pH value to 6.0 or below. The nutrient status of the soil was improved considerably over that in the past. The agronomic characteristics and performance of the 1959 varieties are shown in Table 8. The average yields over a number of years are also shown. Two varieties gave a three-year average yield of about a ton of grain per acre. These were ASF 54-3435 and ASF 54-3437. These varieties are identical to Central 7-303 and Central 7-310. The highest yielding 1959 variety was ASF 3881. This popcorn, along with a number of other multiple-eared varieties gave excellent yields. Four varieties yielded over 3000 pounds per acre. Entomological Evaluation On June 21 and 22, 1956 a 25-ear sample was taken from each replicate of each variety and examined for tip and side injury by the corn earworm, Heliothis zea (Boddie) and also for weevil injury. Injury to the side of the ears by the corn earworm and injury by weevils was too light to make comparisons and the data are not given in this paper. For tip injury by earworms, each ear was given a score (0 to 5) based on the depth from the tip that feeding occurred. The number of ears of each sam- ple having a certain score was multiplied by that score and the resulting products were added and the sum divided by 25 and multiplied by 100. The average score for four replicates of each variety is reported along with the percentage of worm-free ears (Table 9). The method of scoring was as follows: Table 7. The Characteristics and Performance of 18 Popcorn Varieties at Belle Glade, Florida. 1958 Yields, lbs/a @ Variety i/ 15.5% Disease Index 2/ Ear Corn Quality 3/ Wt/Bu. lbs. Off. Volume Test 4/ Weight Volume Test 5/ Times Grown, Years Avg. Yields, lbs/A 15.5% Ames Seed Farms 54-3435 ( Ames Seed Farms 54-3437 ( Iowa 4258 Ames Seed Farms 92-3454 ( Ames Seed Farms 2894-385( Ames Seed Farms 28-2894 Ames Seed Farms A-81 Ames Seed Farms 2894-3138 Nebraska 104 Ames Seed Farms 2694-A34 Purdue 303 Ames Seed Farms 3856-A92 Purdue 31 Purdue 202 Central 4 Hybrid Ames Seed Farms 96-3856 Purdue 32 Iowa 3574 07-303) :C7-310) C07-336) 63 B 1690 1420 1415 1350 1215 1190 1120 930 905 795 780 575 570 550 520 495 435 360 2.6 2.8 1.9 2.3 2.1 2.8 2.4 3.4 1.9 1.9 2.9 2.3 4.1 1.4 2.8 2.5 2.9 2.0 7.5 9.0 8.5 7.5 8.5 8.5 8.5 6.5 8.5 7.0 8.0 6.5 6.0 8.0 7.0 6.5 7.0 8.0 67.8 67.0 67.7 65.9 66.5 65.7 67.0 66.3 65.7 67.6 65.8 66.5 62.0 65.0 65.0 66.1 62.8 64.9 34.0 31.8 37.0 27,0 37.5 36.1 37.0 33.1 33.4 32.2 34.4 33.3 28.0 35.8 37.0 34.7 31.8 36.2 945 900 1035 775 1055 1040 1040 940 960 900 975 950 850 1040 1070 995 950 1045 2405 1990 2045 1670 1290 1920 1670 Varieties 15, 16, and 17 shown as Ames Seed Farm Varieties are identical with the Central Popcorn Co. numbers shown in parentheses, and were the best varieties grown in 1957. LSD .05 405 lbs./A. LSD .05 535 lbs./A. Readings by Miss Alice L. Robert, Plant Pathologist, Corn and Sorghum Section, CCRB-CRD-ARS-USDA. May 26, 195 A score of 10.0 indicates a perfect popcorn ear and a score of 1.0 a very poor ear in appearance. Popping expansion volume ratio Raw: Popped. Cubic inches of popped corn per pound of raw popcorn. Planted February 26, 1958. Harvested June 16, 1958. y/ 8. Table 8. The Characteristics and Performance of 23 Popcorn Varieties at Belle Glade, Florida. 1959. Varieties Vl Yields, Ibs/A C 15.5% Disease Index 2/ Ear Corn Quality I/ Wt./Bu. Ibs. Off. Volume Test / Weight Volume Test 2/ Height,Ft. Stalk Ear Ears/50' Row,No. Erect Stalks at harvest S Times Grown, Years Avg.Yields, Ibs./A @ 15.5% ASFUA381 3455 "3843 28K 3210 lopop 8 3110 ASFB8 5696 3050 Purdue 213 2880 ASFP8 4496 2775 " KA 3538 2750 Iopop 6 2650 ASF96 3843 2605 " 968 3138 2565 " 38 2894 2385 " 81 5696 2080 " 54 34371/ 2050 " A84356 2035 Purdue 32 2015 Nebraska 104 1930 AsF81 4496 1880 "2894-3856 1760 " 84 5696 1680 " 45A 5696 1630 Purdue 202/ 1540 ASF54 34353J 1460 " A-81 1375 3.5 2.0 2.0 2.5 3.5 2.5 3.0 3.5 2.5 3.0 3.5 3.0 3.5 2.0 3.5 3.5 3.5 3.0 3.5 3.0 1.5 3.5 3.0 9.0 8.0 8.5 9.0 8.5 9.0 8.5 8.5 7.5 8.5 8.5 8.5 8.0 7.5 7.5 8.5 6.0 7.5 8.0 8.5 7.5 8.0 8.0 66.5 65.0 65.0 66.5 66.0 65.5 66.o 65.0 66.0 66.5 66.5 64.5 65.0 66.5 65.0 65.0 65.5 65.o 63.5 65.5 64.5 65.5 63.5 38.3 33.6 36.8 40.1 35.1 38.6 36.2 33.9 33.2 34.4 36.9 37.6 36.2 37.8 35.7 35.2 37.4 33.1 37.0 34.5 33.5 35.9 35.1 logo 975 1070 1140 1000 1100 1040 985 950 98Q 1025 1100 1050 1075 1040 1020 o1060o 960 1090 985 985 1075 1025 7.5 7.0 7.0 7.0 7.0 7.0 7.0 7.0 6.5 7.5 7.5 7.0 7.0 6.0 7.0 7.5 7.0 7.0 7.0 7.0 5.5 7.5 7.0 3.5 3.5 4.0 4.0 4.0 3.5 3.5 4.5 3.0 4.0 4.0 3.5 3.5 3.0 4.0 4.0 3.0 3.5 3.5 3.5 3.0 3.5 3.5 114 121 83 104 91 94 96 84 83 96 81 69 49 63 56 51 69 64 62 45 46 43 43 3 2005 1740 14#00 2 1450 1350 2090 1250 L.S.D. for Yields .05 440 Ibs./A; .01 585 Ibs./A., Variety 22, ASF54-3435 is identical to Central 7-303; Variety 23, ASF54 3437 to C7-310. 0.5 resistant to 5.0 susceptible to Northern Corn Leaf Blight. Readings on May 12, 1959. 3 A score of 10.0 indicates a perfect popcorn ear and a score of 1.0 a very poor ear in appearance. Popping expansion volume ratio Popped: Erw. SCubic inches of popped corn per pound of raw popcorn. ___ -5- Score Amount of Injury 0 None 1 Up to 1/8 the length of the ear 2 Up to 1/4 the length of the ear 3 Up to 1/3 the length of the ear 4 Up to 1/2 the length of the ear 5 More than 1/2 the length of the ear. Of the 25 ears in the sample, five ears of representative size were meas- ured to obtain an average for each replicate of each variety. The number of ears per plot had been counted when the popcorn was harvested. The data were analyzed statistically in such a way that the effect of ear length, number of ears per plot, and yield upon the earworm score could be determined. The length of ear did not have a significant effect upon the ear- worm score (r 0.2220). As the weight (r s -0.4203**) and the number (r n 0.2784*) of ears per plot increased the amount of injury as measured by earworm score decreased. Variety C-6-329 had significantly less earworm injury than all other varieties except P-32, C-l-$l, C-6-312, C-55, and C-6-417 in 1956. In 1957, because of low yields, it was necessary to omit some of the varieties from the entomological investigation and to examine only 10 ears per plot. For damage by both corn earworm, Heliothis zea Boddie, and stored- grain insects (predominantly the rice weevil, Sitophilus oryza (L.)) each ear was scored from 0 to 5 to indicate the degree of injury. The scores were averaged and multiplied by 100 for each plot. These examinations were made July 31, 1957, or 56 days after harvest. Between the time of harvest and examination the ears were stored in open bags with no protection against stored grain insects. The method of scoring was as follows: No. Corn Earworm Stored Grain Insects 0 no damage no damage 1 damage to tip 1-10 kernels 2 damage to kernels to one-half 10-20 kernels inch below tip of ear 3 damage to kernels to one and one- 20-30 kernels fourth inches below tip 4 damage to kernels to two and one- 30-40 kernels half inches below tip 5 damage to kernels to more than two and 50 plus kernels one-half inches below tip. Differences among varieties in the degree of earworm damage were non- significant (Table 10). Among the varieties examined, C-7-336 was significantly more resistant than all varieties other than C-7-310 and C-6-408 to stored- grain insects. In 1957, the number of ears yielded per plot did not have a significant effect on the degree of earworm or stored-grain insect damage. In 1958, it was again necessary to omit some of the varieties and to examine only 10 ears per plot because of low yields. Damage by the corn ear- worm was evaluated by assigning a score (0 to 5) to indicate the degree of damage. The scores for each plot were averaged and multiplied by 100. -6- The method of scoring individual ears for corn earworm damage was as follows: Score Amount of Injury 0 None 1 Up to 1/8 the length of the ear 2 Up to 1/4 the length of the ear 3Up to 3/8 the length of the ear Up to 1/2 the length of the ear 5 Greater than 1/2 the length of the ear To evaluate stored grain insect damage 100 kernels were taken from each plot after shelling and observed for the number of damaged kernels. Examina- tions for both corn earworm and stored grain insect damage were made on December 17 and 18, 1958. Covariance analysis indicated a significant negative correlation (r =-0.3712) between stored grain insect damage and ear length but non-significant correlation between ear length and earvorm damage (r -0.0127) and between earworm damage and stored grain insect damage (0.2322). The F value for comparing varieties for earworm damage was significant (F s 2.33* d.f. : 10,30). The multiple range test indicated that Ames Seed Farms 38-2894 had significantly less earworm damage than Ames Seed Farms 2894-3138 or Nebraska 104. (Tablb 11). Ames Seed Farms 92-3454 (C7-336) had significantly less earworm damage than Nebraska 104. The F value for comparing varieties for stored grain insect damage was not significant (F = 1.97, d.f. = 10,30) and was changed little when the regression of damage on ear length was considered (F = 1.92, d.f. = 10,29). The multiple range test showed that Iowa 4258 suffered significantly more stored grain insect damage than all varieties other than Ames Seed Farms varieties 2894- 3856, 54-3437 (C7-310), and 38-2894, when regression on ear length was consi- dered in the analysis (Table 12). When the regression was not considered, the damage suffered by Purdue 303 was also not significantly different than that to Iowa 4258. On July 1 to 3, 1959, ears were rated for earworm damage exactly as in 1958 with the exception that a sample size of 25 ears per plot were examined. Corn was examined for stored grain insect damage using the same method as that in 1958. For each plot the length of five ears was taken to the nearest half-inch. Stored grain insect damage was practically non-existent so no variety com- parisons could be made. Covariance analysis indicated a non-significant negative correlation (r s -0.0364) between ear length and the earworm damage score. The F value for comparing varieties for earworm damage was highly signi- ficant (F s 3.27** d.f. a 22,66) as was that for comparing ear lengths (F a 12.13**' Average ear length and earworm score are shown for each variety in Table 13. The number of significant differences shown by the Student-Newman-Keuls test (Federer, Walter T. 1955. Experimental Design. 544 pp. The MacMillan Company, New York, N.Y.) was relatively small. Significant ** Highly significant Table 9. Earworm Damage, Number, and Length of Belle Glade, Florida. 1956. Variety 7 c-6-329 1 P-32 3 C-1-HY 6 c-6-312 4 C-55 L1 C-6-417 L4 P-31 L8 C-2-HY L2 C-5-401 L3 YS(RS)FU LO C-6-412 2 P-202 8 C-6-337 L9 C-4-HY 5 C-6-303c L6 c-115 9 c-6-343 )0 C-5-HY .5 0-105 Length of Ear, Mm 18.4 16.1 14.7 16.2 17.3 16.0 17.1 16.6 16.5 18.0 16.4 16.3 16.0 15.8 15.3 17.0 17.1 16.6 11.2 Av. number of Ears/Plot 105 121 139 83 110 111 116 115 117 102 102 97 85 124 109 104 125 125 102 Popcorn Ears, % Worm- Free Ears a Scores joined by the same line are not significantly different; others are. Table 10. Variety 0-7-336 C-7-310 0-6-408 0-7-303 C-4-HY 0-7-369 0-7-389 C-7-419 P-32 Earworm and Stored Grain Insect Belle Glade, Florida. 1957. Earworm Damages 163 155 190 193 195 183 160 200 195 Damage to Popcorn Ears. Stored Grain Insect Damages 203 223 228 265 277 290 298 305 313 Earworm Scores 110 119 126 128 130 134 143 143 145 145 146 147 147 148 150 157 161 178 282 a Damage Scores joined by the same line are not significantly different; others are. Table 11. Earworm damage to Popcorn Ears. Belle Glade, Florida, 1958 Variety Ames Seed Farms 38-2894 92-3454(C7-336) A-81 Iowa 4258 Purdue 303 aes Seed Farms 2894-A34 " 2894-3856 " 54-3437(07-310) " 54-3435(07-303) " 2894-3138 Nebraska 104 a) Scores Joined by the same line are not signifi- cantly different; others are. Table 12. Ear length and stored grain insect damage to popcorn ears. Belle Glade, Florida, 1958. Average Ear Length Variety Inches* Not Corrected for regression on Length Corrected Am ies Seed Farms A-81 " 54-3435(07-303) " " 92-3454(c7-336) S 2894-A34 it I It 2894-3138 " 38-2894 " 54-3437(07-310) S t 2894-3856 Nebraska 104 Purdue 303 Iowa 4258 Significantly different from all varieties other than 2894-3856, 54-3437 (C7-310), 38-2894, and Purdue 303. b Significantly different from all varieties other 2894-3856, 54-3437(07-310), and 38-2894. Ames Seed Farms varieties than Ames Seed Farms varieties * F Test for differences in ear length was significant. Earworm Score a An 105 118 130 135 140 148 153 160 178 193 210 5.4 6.5 6.5 6.2 5.8 6.1 6.4 5.9 6.1 5.0 5.7 66 65 66 68 72 75 76 82 70 75 92a 70 69 70 70 70 76 79 82 71 68 90b - --- Table 13. Ear Length and Corn Earworm Damage to Popcorn Ears. Belle Glade, Florida, 1959. Ear Variety Length, Earworm Inches Scorea ASF KA 3881 6.5 174 ASP 3843 28K 6.2 182 ASF 96 3843 6.6 189 ASF KA 3538 6.3 192 ASF 88 5696 7.2 194 ASF 81 5696 6.8 199 AS? 88 4496 6.9 199 Purdue 213 5.9 206 ASF A 81 6.7 216 ASF 84 5696 6.9 217 ASF 54 3437 (07-310) 7.8 217 Iopop 8 5.6 219 ASF 2894 3856 6.4 221 Nebraska 104 6.9 223 ASF 45A 5696 7.0 223 ASF 38 2894 6.2 224 ASF 968 3138 6.2 225 ASF 54 3435 (07-303) 6.9 228 Iopop 6 6.0 231 Purdue 202 7.0 236 Purdue 32 7.0 242 ASF A84356 6.8 246 ASF 81 4h96 6.5 261 a Means joined by the same line are not significantly different; others are. EES 60-5 250 copies SUMMARY AND CONCLUSIONS Tests were begun in 1952 to determine if popcorn could be profitably pro- duced in the Everglades region of Florida. The area is characterized by high rainfall, large corn insect populations and the possibility of an epiphytotic of northern leaf blight annually. Data collected during the eight-year period showed that profitable yields of high quality grain could be produced by planting early in February, by good insect and weed control measures, and by promptly harvesting the grain as soon as the moisture therein had dropped to about 25 percent. Spraying for leaf blight may be necessary. Late maturing varieties (requiring in excess of 115 days) gave higher yields of popcorn with greater expansion ratios. Premature drying caused by northern leaf blight was detrimental to expansion of the popped product. Central Hybrid No. 4 gave a six year average yield of 1920 pounds, Purdue 32 gave a five year average of 1740 pounds, ASF 54-3435 and ASF 54-3437 gave three year average yields of 2090 and 2005 pounds per acre, resp. Tests showed that Florida grown grain when dried properly to prime mois- ture content could, upon popping, give expansion ratios up to 40:1. Normal expansion figures vary from 33:1 to 39:1. Shelling percentages of the varieties varied from 76 to 84 percent grain, which is quite satisfactory. Test weight of the shelled corn was normal. Florida-grown popcorn was shown to be excellent for taste, tenderness and flakiness by numerous testimonials, many of which were voluntary and spontaneous. EES 60-5 150 copies |