Chemical contents in groundnut peg in relation to pre-harvest resistance to Aspergillus flavus

摘要

Pre-harvest Aspergillus flavus infection is one of the most important factors contributing to the production of aflatoxins in groundnut. Concerns over toxic and carcinogenic effects of aflatoxins in groundnut food products have stimulated much effort to reduce, pre-harvest, the fungus infectivity. The objective of present research was to determine groundnut genotypes resisting to A. flavus contamination and chemical levels in their pegs. Forty-seven groundnut genotypes were studied, under inoculated and uninoculated conditions, using a peg-screening method on M3S1B selective medium. The contents of calcium, copper, magnesium, manganese, iron, zinc and tannins in groundnut peg of each genotype were analyzed and compared with the percent peg infection. The results show that groundnut genotypes responded differently in their resistance to the fungal infection only under inoculation condition. The infections were least in US120 (4.10% each) follow by J_(11), 511CC, PRO40-1, Lumpang, ICGX990093 and ICGX990094 genotypes as the percent infection below 30.0%. KK4 x U4-7-5 represented the maximum (95.0%) percentage of peg infection. Among the chemicals analyzed, only calcium concentration in aerial peg and soil peg were significantly negative correlated with percent peg infection, with r = -0.65~(**) and r = -0.53~* respectively. The results revealed that the lower the percent-infected peg of groundnut genotype, the higher calcium content in their pegs.