Wheat phenology and yield under drought: A review

Abstract

The purpose of this review was to characterize the wheat crop phenology under drought conditions, at different stages of crop growth. Effects of drought on wheat plants are variable, and depend on the phenological stage of the plant as well as the duration, intensity and frequency of the drought. The crop evapotranspiration increases over the course of the phenological cycle, reaching a maximum in the growth stage (from the beginning of heading until the end of flowering), which is the most sensitive stage of the crop to drought. At ripening, the evapotranspiration decreases to save and allocate the energy to grain yield. The drought affects the plant density in the initial phase, tiller number per plant in the tillering phase, and plant height in the stretching phase, most severely. At the flowering stage, the processes related to fertilization and fixation of grain are most severely affected, i.e., the number of viable seeds per area decreases. In the grain formation stage, the ability of the source (leaf) to use and translocate the assimilates to the grain is most severely affected, thus affecting the grain weight.