Improving crop yield under drought stress through physiological breeding

Abstract

Drought is recognized as a major constraint that impairs yield of almost all the important crops. To facilitate drought tolerance and maintaining yield under such calamity, a thorough understanding of various physiological traits that govern the yield under water stress condition and integration of tolerance strategies from different disciplines is a prerequisite. Roots are critical in extracting water from soil and their architecture and anatomical traits largely determines crop functioning under water related stress. Various root parameters like deep root with greater xylem vessel radii and lower resistance to water flux can be used as a criterion for selecting drought tolerant genotypes. Physiological factors like water use efficiency (WUE) and transpiration efficiency (TE) are associated with increased yield in a range of crop species under drought. Thus, breeding for improved WUE, TE and various root traits could be beneficial for improving yield under drought stress. While plant physiology improves understanding of the complex network of drought tolerance-related traits, molecular biology and genomics approaches identify the candidate genes and quantitative trait loci (QTLs) associated with these traits. Recently, QTLs for various morpho-physiological and yield traits under drought stress have been identified through molecular mapping approaches and are highly relevant for the selection of drought-resistant genotypes. Thus, understanding the physiological traits of plants under drought and then incorporation of these improved drought-associated-traits through physiological breeding might be helpful in sustaining the crop yield and productivity.