Variability for agronomic traits in sunflower random-mating populations: Correlations, estimated gains from selection and correlated responses to selection

Abstract

Estimated gains from selection and interrelationship among agronomic characters were evaluated in the random-mating sunflower populations Local Open and UAF using data from two seasons (spring and fall). Among 66 combinations of 12 traits included; number of leaves per plant with days to anthesis and head diameter; plant height with seed yield per plant; days to flowering with days to anthesis, days to maturity and head diameter; days to anthesis with days to maturity, head diameter and seed yield per plant; and days to maturity with seed yield per plant showed significant, positive correlations in both sunflower populations during spring. Most often, genetic correlations were slightly higher than their respective phenotypic correlations in UAF sunflower population during spring and fall. But the trend was almost reverse in Local Open during both seasons. Estimates of percentage gain per generation for selection at 20% intensity indicated that this selection would be effective for improving seed and oil yield. The estimated gain for achene yield was 31.33 and 24.38% per generation (Local Open and UAF) when S1 testing was conducted in spring season. Correlated responses to S1 selection for yield and the components of yield indicated that indirect selection for achene yield and oil yield would be effective. Direct selection for yield was estimated to result in favorable increases in all yield components.