MAGNITUDE OF HETEROSIS AND HERITABILITY IN SUNFLOWER OVER ENVIRONMENTS

This study was conducted using 5 cytoplasmic male sterile (CMS) lines and 5 restorers of sunflower, in a line x tester fashions at two locations to determine and quantify the magnitude of heterosis and heritability over environments. The traits studied were days to 50% flowering, days to maturity, 1000-seed weight, seeds head -1 , oil content and seed yield. Heterotic studies revealed that not a single cross combination showed consistent promising results for all traits. Best cross combinations at Peshawar were TS-18 x TR-13(-3.06) for early flowering, TS-18 x TR-6023(- 37.91) for early maturity, TS-4 x TR-6(47.56) for 1000-seed weight, TS-11 x TR-5(80.70) for seeds head -1 , TS-11xTR-6023(98.25) for oil contents and T335xTR-5(117.97) for seed yield. At Mansehra the crosses identified for desirable heterosis were TS-4 x TR-6(-22.45) for days to flowering, T335xTR-13(-56.29) for days to maturity, TS-11xTR-6(30.71) for 1000-seed weight, TS-4 x TR-5(33.39) for seeds head -1 , Ts-4xTR-5(132.23) for oil contents and TS-11x TR-3(30.53) for seed yield Kg/h. Most of the crosses exhibited positive heterosis for all traits however, some of the crosses also depicted negative but desirable heterosis for traits like days to flowering and maturity. Very high heritability estimates were observed for 1000-seed weight, seeds head -1 , oil content and seed yield at both locations. On the basis of seed yield and oil contents the cross combinations TS-335xTR-5, TS-11x TR-3, TS-11xTR-6023 and TS-4xTR-5 are recommended for commercial and further use in plant breeding programs.