PREHARVEST KERNEL INVASION IN GROUNDNUT GENOTYPES BY ASPERGILLUS-FLAVUS AND ITS RELATION TO THE POD SURFACE-AREA

Field and microplot trials were conducted. In microplot experiments the soil was artificially infested by Aspergillus flavus Link ex Fries. In field tests the percentage of A. flavus- affected kernels and in microplot experiments the number of A. flavus colonies emerging from 100 seeds was determined. As the geocarpoplane is the main frontier of pod invasion, pod surfaces were measured and the number of seedborne colonies per 100 cm(2) of pod surface were calculated for each groundnut genotype. Some genotypes, which were similar in colony incidence (counts per 100 seeds), differed markedly from each other in colonization density (number of seedborne colonies as calculated per unit area of pod surface). Cultivar EC-21115 had a low incidence of seed borne colonies of A. flavus; however, the number of colonies per 100 cm(2) of pod surface was high. Cv. Lavkan was low, both, in colony incidence and colonization density. Genotypes low in both these parameters should be tested as potential sources of resistance.