Author(s): Wannows AA, Azzam HK, AL Ahmad SA
The present study was undertaken to study the gene action, narrow sense heritability, interrelationships among traits and path coefficient analysis for grain yield and its components, plant and ear height, leaf area index (LAI), specific leaf weight (SLW) and physiological maturity (Ph. M). Fifteen hybrids produced using a half diallel fashion in 2008 season were evaluated for grain yield and its components and morpho- physiological traits during 2009 season. The obtained results indicated that all estimates of additive (VA) and dominance (VD) variance were significant for all characteristics with exception of additive variance for specific leaf weight Also, dominance variance for leaf area index, plant and ear height, ear length, and number of kernel per row. However the magnitude of VA was consistently larger than that of VD for all characteristics with exception of specific leaf weight, silking date, stay green, 100- kernel weight and grain yield where VD values were larger than VA values.High narrow sense heritability estimates were detected for leaf area index (96%), number of kernel per row (86%), plant height (85%), ear height (83%), physiological maturity (82%), number of rows per ear (77%), ear length (73%) and ear diameter (62%) and Emphasizing that the additive genetic variance was the major component of genetic variation in the inheritance of these traits and the effectiveness of selection for improving these traits. However, moderate narrow sense heritability estimates were obtained for leaf angel (48%), specific leaf area (46%) and 100- kernel weight (44%). While estimates were low for grain yield (39%), silking date (34%), stay green (27%) and specific leaf weight (26%). These results indicated the importance of choosing the suitable segregating generations for exhibiting the best expression of gene of different studied traits. Correlation coefficients among traits indicated that grain yield was positively and significantly associated with number of kernel per row (0.589), ear length (0.465), and leaf area index (0.497).The path coefficient analysis was calculated to detect the relative importance of characters contributing to grain yield. Data showed that each of leaf area index, ear diameter and physiological maturity had high positive direct effects on grain yield.