Genetic base of Indian sunflower (Helianthus annuus L.) cultivars revealed through pedigree analysis.

Abstract

Sunflower (Helianthus annuus L.) is one of the world’s most important oilseed crops with a multitude of uses. Genetic base of this crop as revealed by the pedigree records of released cultivars appears to be narrow because of the frequent use of the same parents and their derivatives in heterosis breeding programmes. Pedigree analysis of 30 sunflower hybrids that have been released from 1980 to 2020 by public sector through hybridization in the country traced back to a few ancestors and thereby increasing the genetic vulnerability to biotic (diseases and insect pests) and abiotic (drought, salinity, heat) stresses. This appears to be insignificant part of the germplasm accessions conserved in Indian gene bank. Rate of infusion of new germplasm in sunflower breeding programmes has also been slow due to repeated use of the same germplasm for development of cultivars. This shows that a vast majority of accessions held in gene bank have made limited contribution in development of modern cultivars. In sunflower, 30% hybrids developed through hybridization have CMS-234A as female parent in their pedigree. Ancestors, RHA-95C-1 and CMS-17A appeared in 13% and 10% hybrids, respectively. Similarly, RHA-1-1, P-93R and RHA-6D-1 appeared in 7%, 7% and 10% cultivars, respectively. Only 6 parents (2 CMS & 4 R lines) could represent 33% of total genetic base of sunflower cultivars developed in the country.This analysis revealed that genetic base of sunflower hybrids is narrow and needs immediate corrective measures by involving trait specific germplasm accessions, exotic and wild relatives in breeding programmes for broadening the genetic base of cultivars. With the advent of modern breeding tools and techniques including various molecular biology tools it has become possible to incorporate genes from various divergent sources systematically in less time and with less financial resources for yield improvement and stabilization. The utilization of wild Helianthus species will lead to broadening of genetic base thus increasing crop resilience towards various biotic and abiotic stresses.