Combining ability and heterosis studies in sunflowrr (Helianthus annuus L.) for yield and its related traits

The research was conducted at the research area of the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad to analyze the performance of seven accessions of sunflower for yield and its related traits during 2014-15. The data were recorded on quantitative traits; days to maturity, plant height, stem diameter, head diameter, number of leaves, achene per head, achene yield per plant, 100-achene weight, filled achene percentage and oil contents and subjected to Analysis of variance, combining abilities, heterosis, correlation and path coefficient analysis. The accessions were significant for studied traits except oil contents. The accessions A-544, A-554 and A-552 showed significant general combining ability effects days to maturity, plant height, stem diameter, head diameter, number of leaves and filled achene %age, achene per head and achene yield per plant. The best cross combination A-546 x A-560 showed significant specific combining ability effect for number of leaves and filled achene percentage. Among reciprocal crosses, the cross A-560 x A-534 proved best for plant height and stem diameter while A-548 x A-546 for number of leaves and achene per head. Heterosis studies revealed that the best cross combination A-560 x A-554 showed maximum increase in heterosis for achene yield per plant and filled achene percentage. Genotypic correlation was higher than phenotypic correlation suggesting that environment effects are very low. Plant height, head diameter, number of leaves and achene yield had significant positive correlations. Correlations of achene yield per plant had significant positive correlations with days to maturity, stem diameter and head diameter. Head diameter, number of leaves, achene per head, 100-achene weight and filled achene %age had positive direct effect on achene yield per plant. While days to maturity, plant height, stem diameter, had negative direct effect on achene yield per plant.