Groundnut under organic farming: Genetic variability and association studies for yield, quality and disease resistance in recombinant inbred lines

A population consisting of 147 RILs derived from the cross TG 49 x GPBD 4 and their reverse cross consisting 20 RILs respectively (F7 generation) were utilized for the study. Both the populations were subjected to phenotyping for quality traits (oil content and protein content), disease resistance (rust and LLS both at 70 and 80 days after sowing) and three productivity traits (pod yield/plant, 100-seed weight and shelling %) for kharif 2009. In both the segregating populations, the analysis of variance indicated significant variation for all the yield traits and diseases, but the variation was found to be less for quality traits. High genotypic and phenotypic variation was observed for pod yield (kg/plant), shelling per cent, rust and LLS at stage I it indicates the presence of considerable amount of genetic variability for these traits whereas in oil content and protein content there is low GCV and PCV. There was a highly significant and positive correlation between the protein and oil content in GPBD 4 x TG 49 population but negative relation in the TG 49 x GPBD 4 population. Highly significant positive correlation was observed in 100-seed weight and pod yield per plant in both the population indicating that breeding for high yield can be achieved without comprising the large seed size, which is a preferred trait for confectionery groundnut. Several RILs superior to best parent were identified for different traits which could be utilized in future breeding programmes.