Assessment of genetic diversity among the maintainer and restorer inbreds of sunflower (Helianthus annuus L.)

Sunflower (Helianthus annuus L.) is one of the most important oilseed crops grown worldwide because of its supreme oil quality and commercial importance. Assessment of diversity among inbreds is a vital prerequisite to select parents for a hybridization programme. Hence, in the present investigation, the genetic divergence of 29 genotypes consisting of both maintainer and restorer inbreds was studied using Mahalanobis (D2) analysis. Genotypes were grouped into eight clusters, in which cluster I was the largest with 13 genotypes. Clusters IV, VI, VII and VIII were the smallest, with one genotype each. The maximum intracluster distance was observed in cluster I followed by II. Maximum inter cluster distance was recorded between clusters II and V followed by clusters II and VII. Days to 50% flowering had the maximum contribution (32.76%) for genetic divergence. Superior mean performance for head diameter, 100 - seed weight, seed yield per plant and oil content was observed in cluster VI whereas earliness in terms of days to 50% flowering and days to maturity was observed in cluster II. Cluster VIII recorded superior mean performance for volume weight and the lowest mean plant height was observed in cluster VII. Hence, hybridization between cluster II (CMS 10B, HA 89B, RHA-1-1) and cluster V (CMS 519B, HA 430B) could create more variability in the segregating generations. Key words: Sunflower, genetic diversity, inbreds, maintainer, restorer.