Genetic divergence studies for yield and physiological attributes in groundnut (Arachis hypogaea L.).

Thirty genotypes of groundnut were evaluated during kharif 2011 in Andhra Pradesh, India, for 19 yield and physiological traits. All the 30 genotypes were grouped into 14 clusters with a variable number of entries in each cluster revealing the presence of a considerable amount of genetic diversity in the material. Cluster I had the maximum number of 10 genotypes, followed by cluster II with 6 genotypes and cluster X with 3 genotypes. The maximum intra-cluster distance was recorded for cluster X (6.31), followed by cluster II (5.13) and cluster I (4.95), revealing substantial diversity within the clusters. The maximum inter-cluster values were observed between cluster III and cluster XII (12.35), followed by cluster V and cluster XIII (12.10), indicating maximum divergence between the genotypes included in these clusters. Cluster means for different traits indicated that none of the clusters contained genotype with all the desirable characters. Among the various traits, the highest contribution towards divergence was found for number of secondary branches per plant (29.89%), followed by crop growth rate (CGR) at 75 days after sowing (DAS) to harvest (18.39%), CGR at 30-75 DAS (10.57%), 100-seed weight (8.51%), plant height (8.51%), SPAD chlorophyll metre reading (6.9%) and harvest index (5.75%). The data on inter-cluster distances and per se performance of the genotypes were used to select genetically diverse and agronomically superior genotypes. The genotypes exceptionally good for one or more traits were CAUG-1, CSMG 2006-6, LGN 123, R- 2001-2 and TCGS 150.