Drought Stress Effect on Crop Pollination, Seed Set, Yield and Quality

Abstract

The effect of drought stress on crop growth and yield has become more common worldwide in the last two decades. The reproductive stage is the most criti- cal stage for drought stress during crop growth, because it strongly impacts yield and seed quality. Improving crop growth and yield under drought is thus a major goal of plant breeding. Drought stress negatively affects flower pollination by decreas- ing the amount of viable pollen grain, increasing the unattractiveness of flowers to pollinators, and decreasing the amount of nectar produced by flowers. Consequently crop seed set is lowered. Moreover, drought stress affects crop yield by reducing grain yield and all yield components. The correlation is clear between crop pollina- tion, seed set and yield. Drought stress not only affects seed production, but also affects seed quality such as germination and vigor tests. In this chapter we review the currently available information on pollination, yield, and yield components and seed quality under drought. We give an outlook towards the physiological and bio- chemical processes involved in the reduction of crop yield in response to drought stress at the reproductive stage. We focus on physiological processes of plant repro- ductive organs in response to drought stress at anthesis and the attractiveness of the flowers to pollinators. Here we help plant breeders to select drought tolerant traits by understanding the correlations between pollination, yield, yield components and seed quality under drought stress at reproductive stage and to explain how drought stress effects final yield and seed quality during this stage.