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 th e soil was artificially infested by Aspergillus flavus Link ex Fries. In field tests the percentage of A. flavus- affected kernels and in mi croplot experiments the number of A. flavus colonies emerging from 100 seeds was determined. As the geocarpoplane is the main frontier of po d invasion, pod surfaces were measured and the number of seedborne col onies per 100 cm(2) of pod surface were calculated for each groundnut genotype. Some genotypes, which were similar in colony incidence (coun ts per 100 seeds), differed markedly from each other in colonization d ensity (number of seedborne colonies as calculated per unit area of po d surface). Cultivar EC-21115 had a low incidence of seed borne coloni es 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 co lonization density. Genotypes low in both these parameters should be t ested as potential sources of resistance.