Studies on presowing drought hardening of wheat

Abstract

The effects of presowing drought hardening of wheat on subsequent leaf relative water content (RWC) and grain yield were assessed under a number of environmental conditions.

In general, the treatment reduced the rate at which critical levels of RWC developed during periods of moisture stress, but not necessarily the final value to which the RWC fell. No differences were found in any of the measured parameters during periods when there were no internal water deficits.

Grain yield increases due to the hardening treatment varied "from 0 to 20%" in the different experiments. This variation is explained in terms of both the phenological stage at which RWC differences occurred and the transient effect of the RWC differences.

The results are also discussed in relation to both the cause of the observed RWC differences and the potential practical role of the technique in arid zone agriculture.