EVALUATION OF SUNFLOWER GENOTYPES UNDER LOAMY SAND AND CLAY SOIL CONDITIONS

Twenty-six genotypes of sunflower (16 F₁-hybrids, four female lines, four restorer lines and two check varieties; Sakha 53 and Giza 102) were evaluated under two contrasting environments, i.e., loamy sand soil at A.R.C., Arab El-Awamer Res. Stn., and clay soil at Assiut Univ. Exper. Farm in season 2016. Genotypes mean squares of 13 studied traits was significant (P<0.01) either in the separate or in the combined analysis. The differences between the two environments were significant for all traits except head diameter (HD).  The genotype x environment interaction was significant for all traits, indicating differential responses of genotypes to the two environments. The F₁-hybrids, females and males were earlier than the two checks in days to 50% flowering. The fertile clay soil delayed days to 50% flowering than loamy sand soil. The phenotypic (PCV%) and genotypic (GCV%) coefficients of variability were low, and heritability in broad sense was intermediate (43.17%) for days to 50% flowering.  The combined analysis of plant height showed high PCV (13.58%), GCV (11.81%) and heritability (75.58%). The GCV of head diameter was high and reached 15.95, 14.41 and 11.84% at loamy sand, clay soil and combined analysis; respectively. Stalk diameter was larger at clay than at loamy sand soil, and heritability estimates were 74.19, 77.05 and 66.67% at loamy sand, clay soil and combined analysis; respectively. Four of the F₁-hybrids was heavier in 100-seed weight than the checks. The GCV and heritability estimates were high for 100-seed weight. Husk % and husk; g of 100 seeds tended to be higher at loamy sand than at clay soil. The combined means of oil % showed that five hybrids significantly exceeded the better check Giza 102. Oil % was higher at loamy sand than at clay soil. Heritability estimates of oil % were high at both locations (97.86 and 86.25%) and very low (5.69%) from the combined analysis, because of the large mean squares of GxE interaction. Kernel weight in 100 seeds was higher at loamy sand than at clay soil. The GCV and heritability estimates were high for kernel weight. Number of seeds/head was higher at clay soil than at loamy sand. Three F₁-hybrids significantly exceeded Sakha53in kernel weight from the combined data.  The GCV and heritability estimates were high for NS/H. Seed yield/head and oil yield/head were higher at loamy sand than at clay soil, and four F₁-hybrids were significantly better than the check. High estimates of GCV and heritability were high for NS/H. The GCV estimates in seed yield were 43.48, 39.33 and 33.57%, and heritability were 98.85, 96.67 and 75.22% at loamy sand, clay soil and combined analysis; respectively. The resulted indicated that the genetic materials should be evaluated under diverse environments to get reliable estimates of genetic parameters