Performance of wheat and triticale cultivars in a variable soil-water environment. II. Evapotranspiration, water use efficiency, harvest index and grain yield

Abstract

This communication, based on a 3-year field study, describes the drought susceptibility of 17 cultivars of wheat and triticale, expressed in terms of grain yield, harvest index, pre- and post-anthesis evapotranspiration (ET) and water use efficiency (WUE). At the time of sowing, the available water (between-0.02 MPa and -1.5 MPa) in the soil profile varied between 12.7 and 17.6 cm depending upon the year. A large proportion of this water was consumed by the plants before anthesis, in the unirrigated treatment, leaving on average only 4.2 cm water in the initial 150-cm soil profile. However, precipitation in the post-anthesis phase increased the amount of available water. At crop maturity the soil profile had almost no available water. There were no differences in ET or WUE among the varieties studied. Grain yield and harvest index increased with increase in ET up to a certain level. Whereas the proportion of water used in the post-anthesis phase was important in irrigated plants, both pre- and post-anthesis water use were important in unirrigated wheat. Increase in ET decreased WUE but increased the harvest index. No relationship could be deduced between drought susceptibility and pre- and post-anthesis water use.