Abstract only

Moisture stress is known to be one of the main limiting factors affecting realization of yield potential in wheat. Development of drought tolerant varieties, in addition to the proper management practices, can contribute to preventing yield reduction under the water shortage conditions. For this purpose, a complex study was conducted to screen selected wheat germplasm for drought tolerance under the specific environmental conditions. The studies were carried out in 1999-2001 at Gobustan Zonal Station of Azerbaijani RI of Agriculture under rainfed conditions. Material of the study included high yielding winter bread wheat varieties that had been developed by the institute and released for Highland Shirvan such as Gobustan, Azamatli-95 and Qiymatli-2/17 , as well as the check variety Bezostaya-1. To characterize the water regime, the rate of general water supply ( GWS), daily water deficiency (DWD), residuary water deficiency (RWD), and moisture-holding capacity (MHC) of the flag leaf during ontogenesis were measured. GWS of the leaves drops from the stage of booting to the end of vegetation in all studied varieties. The fact can be explained by physiological senescence and reduction in soil humidity. At the same time, GWS of leaves in the most (70- 75%) of the new high-yielding varieties insignificantly differs from that of the check at the beginning of vegetation period, while this difference increases by 2-3% by the end of vegetation period. In all of the investigated varieties, DWD and RWD of the leaves tend to increase from the booting stage to the wax stage. At the booting and heading stages, DWD of the leaves in all varieties equals to 10-12%, while RWD to 2-4%. During the grain filling and the milk stages, when the soil moisture content decreases, DWD and RWD increase andreach27- 35% and 13-17% accordingly. It is noteworthy that differences among the varieties are not sharply pronounced according to these traits. The WRC values of the leaves in the studied wheat varieties at the stages of booting and heading are close to 47-50% and 31-37% respectively. During the grain filling and at the wax stage, WRC Of the leaves of the new high-yielding varieties are higher than that of the check by 10-12%. The results of the study suggest that determination of water regime values can be useful for estimating of wheat drought tolerance. The other conclusion is that Gobustan and Azamatli-95, introduced from the international nurseries of CIMMYT and ICARDA, possess enough drought tolerance to be grown under rainfed conditions.

English

0408|AGRIS 0401|AL-Wheat Program

Juan Carlos Mendieta

CIMMYT Publications Collection