Estimation of Combining Ability and Gene Action in Some Egyptian Wheat Landraces

FIVE LANDRACES from wheat (Triticum aestivum L.) collected from diverse areas of Egypt and their ten possible crosses as well used to establish the experimental materials for this investigation. We desire to assess the variations among wheat genotypes and available crosses to estimate the magnitude of general combining ability (GCA) and specific combining ability (SCA) for physiological traits, yield and yield components. Mean squares for parent showed high significant for net photosynthesis rate (Pn), transpiration rate (E), stomatal conductance (C), days to maturity, no. of kernels per spike and 1000- kernel weight. Crosses mean squares showed high significant for Pn, E, C, no. of kernels per spike and 1000-kernel weight, on the other hand there was no significant for no. of spikes per plant and grain yield. High significant recorded for Parent vs crosses mean squares for E, C, no. of kernels per spike and 1000- kernel weight. The parental lines L₁ exhibited significant positive desirable GCA effects for Pn, C and grain yield/plant. The most desirable SCA effects recorded by cross namely L₁x L₃ for C, days to maturity, no. of spikes per plant and grain yield /plant, also, L₁ x L₄ for E, no. of kernels per spike and grain yield/plant. Although that there was a positive and negative correlation among traits study but was not significant value except the correlation between transpiration rate (E) moreover, stomatal conductance (C) was positive significant value. (r= 0.90).