Physiological characteristics of high-yielding and high-protein wheats in Canadian prairies: water use and water use efficiency

Abstract

The moisture condition in the Canadian prairies is often not favourable to wheat growth especially during grain-filling stage (McCaig and Clarke, 1995) because of the limited precipitation, high temperature and high wind speed. Under this environment, new cultivars with both high yield and high protein concentration should have either higher evapotranspiration (ET) or higher water use efficiency (WUE), or both relative to old low- yielding cultivars. Few studies have been done to compare water use among wheat cultivars released at different periods of breeding (Slafer et al., 1993). Research conducted in Australia revealed that new high-yielding cultivars had higher WUE which was attributed to higher grain yield and higher harvest index, while ET did not change (Siddique et al., 1990a) or was even reduced (Siddique et al., 1990b). In a comparative study in the Canadian prairies, Cutforth et al. (1988) found that four wheat cultivars ( two common wheat and two durum cultivars), which were different significantly in yield, did not differ in ET. Similarly, McNeal et al. (1971) found no difference in ET among five wheat varieties, which were different in height. The objective of this study was to estimate the differences between old cultivars and new high-yielding and high-protein cultivars in ET and WUE in the Canadian prairies.