Study on general combining ability of inbred lines and heterosis of sunflower crosses in different moisture conditions

To study general combining ability (GCA) and estimation of heterosis in sunflower inbred lines for seed yield and other three agronomic traits، 68 inbred lines crossed with open pollination variety Lakumka. In next year inbred lines along with topcrosses were planted in RCBD with 2 replications under two moisture conditions in Sararood Agricultural Research Station. Analysis of variance in both moisture conditions showed significant differences among inbred lines and topcrosses in 1% level of probability for all traits that means there were high genetic variation among genotypes under study. The highest seed yield in drought stress condition were belonged to SIL-109 inbred line with 14. 6 and SIL-175×lakumka topcross with 38. 6 g/plant. In non-stress condition SIL-102 inbred line and SIL-99×lakumka topcross had the highest seed yield with 26. 7 and 32. 2 g/plant، respectively. Average seed yield of inbred lines and topcrosses in non-stress condition were two times more than stress condition. Heterosis for seed yield in stress and non-stress conditions were 25. 25 and 43. 77 percent، respectively. Considering heterotic combinations in both conditions showed that more number of topcrosses had positive heterosis under non-stress condition as compare to drought stress condition and showed better yield potential. Estimation of GCA under both moisture conditions revealed that GCA of inbred lines increased in stress as compare to non-stress condition. Drawing biplot of GCA for inbred lines showed that 8 and 10 inbred lines were close to seed yield vector for stress and non-stress conditions، respectively and had high GCA.