15.5 Concluding remarks

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Drought resistance is clearly a multifaceted adaptive feature of vascular plants. Some mechanisms responsible for survival in nature or improved yields under drought have been outlined, but almost certainly still more await discovery. Existing knowledge already highlights that a mix of divergent traits has evolved across a wide range of taxa in response to drought stress, including drought seasonality and intensity.

Survival in nature is testimony to the enduring success of such features, while a steady increase in wheat yields over the past 150 years bears testimony to the efforts of crop scientists. Improvements in drought resistance are possible via breeding and selection for improved genotypes, but selection criteria are most useful when based upon an appreciation of underlying processes rather than pure empiricism.

While most instances of crop improvement cited here have been based on wheat, examples can also be drawn from other crop species. Experience with wheat provides the incentive to improve the general drought adaptation of new crops where genetic variation exists with respect to water use attributes.