Two field experiments were carried out at Sidi Salem Directorate, Kafr El–Sheikh Governorate, Egypt, during the two successive winter seasons of 2011/2012 and 2012/2013to study the effect of four nitrogen fertilization rates (0, 37.5, 75 and 112.5 kg N/fed) and three phosphorous fertilization rates (0, 15 and 30 kg P2O5/fed) on the growth characters, yield, its component and some chemical properties of three bread wheat cultivars (Gemmeiza 9, Sakha 93 and Giza 168).The experimental design was split split plot design in four replications.
The obvious results of this investigation can be summarized as follows:
All traits of wheat under study, i.e. No. of tillers/m2, No. of spike/m2, plant height, spike length, No. of kernels/spike, 1000-kernel weight, kernels weight/spike, straw yield/fed, grain yield/fed, biological yield/fed, harvest index, kernels nitrogen content (%) and grain protein yield/fed showed significantly increased by increasing nitrogen fertilizer rates, except kernels phosphorous content (%). Application of 112.5 kg N /fed significantly gave the maximum values of all traits. Increasing phosphorous fertilizer rates up to 30 Kg P2O5/fed significantly increased No. of tillers/m2, No. of spike/m2, plant height, spike length, straw yield/fed, grain yield/fed, biological yield/fed and kernels phosphorous content (%) in the two seasons. While, No. of kernels/spike, 1000-kernel weight, kernels weight/spike, harvest index, kernels nitrogen content % and grain protein yield/fed were not affected by increasing phosphorous fertilizer rates. The results showed that wheat cultivars were significantly differed in all traits studied under study in the both seasons, except biological yield kg/fed, kernels nitrogen content (%) and kernels phosphorous content (%). Gemmeiza 9 cultivar significantly surpassed Sakha 93 and Giza 168 cultivars in plant height, spike length, 1000-kernel weight, kernels weight/spike, grain yield/fed, harvest index and kernels protein yield/fed in the both seasons, while, Sakha 93 recorded the highest values of No. of kernels/spike. Morever, Giza 168 surpassed the other two cultivars in No. of tillers/m2, No. of spike/m2 and straw yield/fed. The first order interactions between (112.5 kg N/fed X 30 Kg P2O5/fed), (112.5 kg N/fed X Gemmeiza 9) and (30 Kg P2O5/fed X Gemmeiza 9) as well as the second order interaction between 112.5 kg N/fed X 30 Kg P2O5/fed X Gemmeiza 9 were significantly recorded the greatest grain yield/fed as compared with the others interactions in the both seasons. It could be summarized that sown wheat Gemmeiza 9 cultivar and fertilization by 30 Kg P2O5 + 112.5 kg N/fed maximized grain yield per unit area.