COMBINING ABILITY FOR COMPONENTS OF RESISTANCE TO EARLY LEAF-SPOT ANDYIELD OF INTERSPECIFIC AND INTRASPECIFIC PEANUT LINES

Seven interspecific peanut lines and the cultivar <<Southern Runner>> were crossed in a half-diallel, i.e. without reciprocals. F-1 plants w ere selfed and F-2 progenies evaluated for early leaf spot reaction an d yield The purpose of the study was to ascertain from F-1 and F-2 pop ulations, crosses which were most likely to give the greatest expressi on of early leaf spot resistance and yield. Field early leaf spot asse ssment was made using the Florida leaf spot rating scale and determina tions were mode for lesion diameter, amount of sporulation, and latent period in both the field and laboratory. Genetic analysis was perform ed using the Griffing method 2 model 1. Significant differences existe d among crosses for visual leaf spot rating, latent period, and amount of sporulation in the F-2 generation (P=0.05). Pod yield based on ind ividual plants, differed significantly (P=0.05) among the F-2 progenie s but not in the F-1. little heterosis was found among the F-1 hybrids . Performance in the F-1 was not reflected in the performance of the F -2 as rank correlation between the two populations for pod yield was l ow (r=0.32) and not significant (P=0.05). Combining ability effects (b oth general and specific) were significant for yield and disease param eters in the F-2 generation.