Genetics of Staygreen Trait and its Relation to Drought Tolerance in Sunflower Helianthus annuus L

Abstract

The present investigation was conducted to study the inheritance of staygreen newlinetrait and to identify superior recombinants and SSR markers associated with staygreen newlinethat imparts drought tolerance. Two staygreen genotypes, DSR14 and DSR47 were newlineidentified as drought tolerant and DSR56 and DSR20 as moderately tolerant by newlinecharacterizing the root traits under different soil moisture regimes. Fifteen hybrids newlinedeveloped by hybridizing contrasting parents in half diallele were evaluated for root newlinetraits under moisture stress and non-stress conditions. High magnitude of SCA variance newlinethan GCA variance was observed for most of the root and morpho-physiological traits newlinestudied under both water regimes. Two drought tolerant parents, DSR14 and DSR47 newlineand three hybrids viz., RHA274 × DSR14, CMS234B × DSR47 and DRSI 411 × newlineDSR14 were found to be good general and specific combiners respectively. newlineInheritance study of staygreen trait from two F2 populations (RHA274 × DSR14 newlineand CMS234B × DSR47) indicated dominant epistatic gene interaction with 12 newlinesenescent: 3 moderately staygreen: 1 staygreen ratio. Genetic variability studies newlinerevealed high GCV and PCV for seed yield per plant, leaf area, head diameter and test newlineweight under stress while low under non-stress condition. High heritability and GAM newlinewas observed for seed yield per plant, test weight, staygreen trait and leaf area under newlineboth the water regimes. Seed yield per plant had significant positive correlation with newlinedays to maturity, plant height, SCMR, leaf area, head diameter, staygreen score and test newlineweight under both the water regimes. newlineFrom the present investigation, the recombinant lines viz., 55-5, 96-1, 55-6 and newline133-4 from maintainer cross and 45-2, 242-6, 326-5 and 96-7 from restorer cross were newlinefound to be significantly high yielding under both water regimes. Single marker analysis newlinein two F2 populations revealed the markers ORS1146, ORS511, HA4011 and ORS995 newlinewere associated with staygreen and drought related traits studied.