COMPARISON OF COMPONENTS OF RESISTANCE IN PEANUT TO LATE LEAFSPOT IN DIFFERENT ENVIRONMENTS

Little is known about the consistency of the resistance reaction of peanut (Arachis hypogaea L.) genotypes to late leafspot (Mycosphaerella berkeleyi Jenk.) in varied environments. This study was conducted to determine resistance reactions of peanut genotypes in two disparate environments. Four peanut lines with known levels of resistance to late leafspot in Florida were used to create 12 cross combinations. Parents and segregating generations from these crosses were grown at Gainesville, FL, and Kasinthula and Chitala, Malawi and inoculated with late leafspot. Latent period (LP), lesion diameter (LD), and amount of sporulation (SP) were evaluated. Measurements of the components at Gainesville were significantly correlated with those at Malawi. The correlations between locations for each component were LP, r = 0.52; LD, r = 0.64; and SP, r = 0.64. In both locations LP was negatively correlated with LD (r = 0.55) and SP (r = - 0.63); LD and SP were positively correlated (r = 0-44). Narrow-sense heritability estimates were similar at Gainesville and Malawi. Based on parent-offspring regression, heritabilities averaged 0.62 for LP, 0.55 for LD, and 0.42 for SP. Realized heritability estimates in Malawi were 0.69 for LP, 0.63 for LD, and 0.51 for SP.