Response of some wheat cultivars to moisture stress and nitrogen fertilization

الملخص EN

This investigation was carried out at the experimental farm of: faculty of Agriculture and Veterinary medicine, Thamar University, Thamar governorate, Yemen, during 2003/2004 and 2004/2005 growing seasons.

The main objective of this study was to investigate the response of two wheat cultivars to water stress imposed at some different growth stages and to nitrogen rates.

A split -split plot design with three replications was used.

Five irrigation treatments ( wl= full irrigation, w2= water stress at tillering stage, w3= water stress at stem elongation stage, w4= water stress at heading stage and w5= water stress at grain filling stage ) were occupied the main plots, four nitrogen rates (nl= 60, n2=120, n3= 180 and N4 = 240 kg N/ ha) were assigned to the sub- plots, whereas both cultivars (Saba and Gahran) allocated the sub - sub plots.

Results indicate that water stress imposed at the different growth stages under this investigation has reduced significantly number of spikes/ m , number of kernels/ spike, 1000- kernel weight (g) , grain yield t / ha, biomass yield t / ha and water consumptive use m / ha .

However, imposed water stress at the different growth stages had no significant effect on harvest index trait.

Concerning the nitrogen rates, the results revealed that increasing nitrogen levels from 60 to 240 kg N / ha increased significantly these traits in both seasons.