Response of grain yield and some of its components, water produvtivity and nitrogen use efficiency for some bread wheat cultivars to N-rate under deficit irrigation, induced via corrugation method, on vertisol

. The adopted treatments were assessed in a split- spilt plot design, with three replicates. Grain yield and its components, water productivity and N-use efficiency, for the adopted wheat cultivars, were in consideration. The most important findings could be summarized as follows: . Irrespective of wheat cultivars and N- rates effects, wheat grain yield was significantly increased under corrugation practice by 8.96 and 10.47%, in the first and the second seasons, respectively, as compared with the farmer's irrigation practice. The grain yield components; i.e., number of spikes/m2, number of kernels/spike and 1000-kernel weight traits seemed to increase, with different levels of significance, under corrugation practice in the two seasons of study. The saved irrigation water ranged between 17.21 and 16.29%, respectively, in the first and second seasons, respectively. Corrugation practice exhibited higher values for water productivity and N-use efficiency in the first and second seasons, comparable with the farmer's irrigation practice. The improved values, for all investigated parameters, under corrugation practice, could be ascribed to its potency to optimize soil water in the root zone throughout the even water distribution over the field during the entire growing season., Regardless of the influence of both irrigation practices and N-rates, grain yield of Sakha 94 cultivar surpassed those for Giza 168 and Gemmeiza 9 cultivars with different significant levels, in the first and second seasons, seasons of study. Gemmeiza 9 cultivar exhibited higher values of number of kernels respectively. Sakha 94 cultivar exhibited higher number of spikes/m2 than these of Giza 168 and Gemmeiza 9 cultivars and the differences were significant in the two / spike and 1000- kernel weight than those of Sakha 94 and Giza 168 cultivars. However, the significant levels differed in the two successive seasons.