Title Page
 Table of Contents
 List of Figures
 List of Tables
 Part I: Literature review
 Part II: Section No. 1. Mechanical...
 Part II: Secion No. 2. Correlation...
 Part III: Appendix No. 1. The influence...
 Part III: Appendix No. 2. Preconditioning...
 Biographical sketch

Group Title: Physical and chemical properties of resistance exhibited by certain genotypes of Arachis hypogea to invasion by aflatoxin producing Aspergillus spp. /
Title: Physical and chemical properties of resistance exhibited by certain genotypes of Arachis hypogea to invasion by aflatoxin producing Aspergillus spp.
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00098186/00001
 Material Information
Title: Physical and chemical properties of resistance exhibited by certain genotypes of Arachis hypogea to invasion by aflatoxin producing Aspergillus spp.
Physical Description: 77 leaves : ill. ; 28 cm.
Language: English
Creator: LaPrade, Jesse Cobb, 1941-
Publication Date: 1973
Copyright Date: 1973
Subjects / Keywords: Plant Pathology thesis Ph. D
Peanuts -- Breeding   ( lcsh )
Peanuts -- Diseases and pests   ( lcsh )
Dissertations, Academic -- Plant Pathology -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
Abstract: Data froK inoculations of whole, shelled peanuts from 165 Florida breeding 3.ines with conidia from three isolates of the Aspergillus flavus group (N.R.R.L. 3794, N.R.R.L. 2999, and one Florida isolate) revealed statistically significant differences in tolerance to colonization by the fungus. If seed coats were punctured with a needle or abraded with carborundum before inoculation there were no significant differences in tolerance among the lines. When intact seeds were soaked in an aqueous solution of 1.0 per cent 2, 3, 5-triphenyl-2H-tetrazoliuni diloride (T.Z.C.), a uniform reduction of T.Z.C. occurred on the cotyledons of the susceptible lines but not those of the tolerant lines. This suggested that the seed coats of the tolerant lines were not as permeable as those of the susceptible lines. Aqueous extracts of intact seeds of both tolerant and susceptible lines stimulated' germination of A. flavus conidia when compared to conidia incubated in distilled water. Diethyl ether extracts of intact seeds of tolerant peanut lines revealed no germination inhibition when compared with conidia incubated in distilled water. Thus an intact testa was required for tolerance and appeared to function as a mechanical barrier to penetration by the fungus. Wax- like accumulations were noted in scanning electron micrographs on the testes of dried peanut seed. Seeds from breeding lines which were tolerant to colonization by Aspergillus flavus (N.R.R.L. 2999) appeared to possess more of the wax-like accumulations than did several which were highly susceptible. Extraction of waxes and lipids from Intact seeds with dilorofom: methanol, 2:1 (v/v) , for up to 5 minutes increased the susceptibility of the extracted seeds. No reduction in germination percentage of the seed extracted for 5 minutes was noted. A suspension of A. flavus conidia was placed on the dried solvent residue from a 5 minute and a 2 hour extraction of intact tolerant peanut seed. Germination of A. flavus conidia was slightly stimulated by the residue, compared to distilled water. It appears that the wax-like accumulations help prevent A. flavus from penetrating the intact seed coat. Several preconditioning factors that fluctuate under ordinary gracing and storage conditions were shown to affect the tolerance expressed by two tolerant breeding lines and the moderately tolerant Florunner variety. Pod rot caused primarily by severe nematode infections on Florunner peanuts led to higher levels of aflatoxin contamination under field conditions compared with pod ret caused primarily by fungi. Peanuts of a tolerant breeding line dug 5 weeks before or 1 week after inoculation were more susceptible than peanuts dug at optimum maturity. Tolerance was lost after 1 year of storage of shelled peanuts coTipared with non-shelled peanuts of the same tolerant genotype, The term tolerance as used throughout this context refers to a variable level of infection by fungi of the A. flavus group on peanuts of breeding lines and cultivars. This term was used to differentiate the reaction observed in this study from a hyper sensative reaction.
Thesis: Thesis--University of Florida, 1973.
Bibliography: Includes bibliographical references (leaves 69-76).
General Note: Typescript.
General Note: Vita.
Statement of Responsibility: by Jesse Cobb LaPrade.
 Record Information
Bibliographic ID: UF00098186
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: alephbibnum - 000413910
oclc - 37852566
notis - ACG1044


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Table of Contents
    Title Page
        Page i
        Page ii
    Table of Contents
        Page iii
        Page iv
    List of Figures
        Page v
        Page vi
    List of Tables
        Page vii
        Page viii
        Page ix
        Page x
        Page xi
        Page 1
        Page 2
        Page 3
        Page 4
        Page 5
    Part I: Literature review
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
    Part II: Section No. 1. Mechanical tolerance of selected genotypes of dried peanuts to colonization by strains of Aflatoxin producing Aspergillus spp
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
    Part II: Secion No. 2. Correlation of peanut seed coat surface wax accumulations with tolerance to colonization by Aspergillus flavus
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
        Page 43
        Page 44
        Page 45
    Part III: Appendix No. 1. The influence of peanut moisture content on the reliability of the screening technique used to determine tolerance of breeding lines
        Page 46
        Page 47
        Page 48
        Page 49
        Page 50
        Page 51
    Part III: Appendix No. 2. Preconditioning factors affecting colonization by Aflatoxin producing Aspergillus spp
        Page 52
        Page 53
        Page 54
        Page 55
        Page 56
        Page 57
        Page 58
        Page 59
        Page 60
        Page 61
        Page 62
        Page 63
        Page 64
        Page 65
        Page 66
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
    Biographical sketch
        Page 77
        Page 78
        Page 79
        Page 80
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