Effect of Nitrogen Rates on Growth and Yield of Some Wheat Genotypes Under Post- anthesis Water Stress Levels

Abstract

The experiment was conducted during the seasons of 2013/2014 and 2014/2015 at Dongola research station farm high terrace. Dongola, Northern State, Sudan. The objective of this study was to determine the effect of nitrogen levels, verities and irrigation intervals on growth and yield of wheat. Experimental design used was randomized complete block in split-split plot arrangement with three replications. The main plot consisted of three water intervals (7,14 and 21days) and the subplots consisted of two varieties (Wadi El Neil and EL Neileen) while the sub-sub plot consisted of four nitrogen levels (43, 86 and 129 kg N/ha) . The vegetative and reproductive growth parameters studied were plant height, number of tillers /meter square, leaf area index. Yield and yield components parameters were spike length, number of grains/spike, thousand grain weight, spike index, grain yield, biological yield and harvest index. Water use efficiency parameters were drought tolerance index. stress susceptibility and stress tolerance index. Nitrogen use efficiency parameter was used as the efficiency of nitrogen. Nitrogen significantly affected all vegetative growth parameters in both seasons with the exception on leaf area index which exhibited significant differences in the second season only. Irrigation intervals affected all vegetative growth in both seasons . Wheat varieties significantly affected leaf area index in both seasons and plant height in the first season. Nitrogen fertilizer significantly affected all yield and yield components parameters in both seasons with the exception of spike length which exhibited significant in the second season only. Irrigation intervals affected significantly some of the yield components in both seasons as biological yield , yield and harvest index. There were significant differences among wheat varieties in number of grains /spike and harvest index in both seasons and thousand grain weight and biological weight in the first season and yield in the second season. Water use efficiency are presented in from of tolerance index, (TI) stress stability index and stress tolerance index for all treatments in tolerance index and stress stability. Mean while stress tolerance showed significant difference for both season and application of 129 kg N/ ha gave the greatest values. Nitrogen use efficiency significantly decreased with the increase of nitrogen rate in both seasons.