Relationships between fungi Aspergillus flavus infestation and aflatoxin production and agronomic characteristics, yield components and isozymes and protein patterns of peanut lines

One of the serious problems of peanut seeds consumption is the production of aflatoxin caused by fungi Aspergillus flavus group. Breeding for less A. flavus infestation and aflatoxin production in seed are the alternative methods for solving this problem. Thus, this study was conducted to evaluate the characteristics used for selection lines having less A. flavus infestation and aflatoxin production to improve the efficiency of selection. In the study of relationships between A. flavus infestation and aflatoxin production, and agronomic characters and yield components found the significant difference among the varieties in most of the characters study, except days to 50 percent flowering and seed length. The study of correlation coefficient revealed that some components of seed characters (seed thickness) and some seed coat and pericarp characters (seed coat weight) had the positive correlation coefficient with aflatoxin production in seed. While some yield components (no. of mature pods per plant) and some components of seed (seed moisture percentage) had the positive correlation coefficient with A. flavus infestation in field, and seed coat character (tannin percentage) had the negative correlation coefficient with A. flavus infestation in laboratory. On path-coefficient analysis, days to 50 percent flowering and number of branches of growth characteristics had the high negative and positive direct effect on aflatoxin production in seed, respectively. Among the yield component characteristics, number of mature pods per plant had the high positive direct effect on A. flavus infestation on seed in the both field and laboratory, While number of immature pods per plant, number of seed per plant and number of seed per pod had the high positive direct effect on A. flavus infestation on seed in field. When the seed coat and pericarp characteristics were considered, seed coat weight was found to have the negative direct effect on aflatoxin production in seed and seed coat thickness and seed coat percentage were found to have the high positive and negative indirect effects, respectively. Moreover, seed coat percentage and tannin percentage had the high positive direct effect on A. flavus infestation on seed in field. Among the seed components, seed thickness had the positive direct effect on aflatoxin production in seed, In addition seed moisture percentage had the positive direct effect on A. flavus infestation on field seed. Isozyme patterns of esterase from stem, leaf and cotyledon of the 4, 7 and 9 days seedlings could not identify the difference between the resistant and susceptible cultivars based on A. flavus infestation on seed and aflatoxin production in seed. The 18 protein patterns were identified but none of them could be use to specify the cultivars resistant A. flavus infestation and aflatoxin production in seed.