Limited-transpiration trait for increased yield for water-limited soybean: From model to phenotype to genotype to cultivars

Abstract

Soybean (Glycine max (L.) Merr.) is the most widely grown grain legume in the world due to its many uses in feed, food, and industrial products. However, soybean yield is particularly sensitive to soil water deficits, and seemingly, opportunities exist to increase yield by improving specific plant traits. One trait that has proven to be especially useful is the limited-transpiration trait in which water loss by the plants is constrained by the plant under high atmospheric vapor pressure deficit conditions. This chapter reviews the integrated studies at several levels and disciplines to identify the trait, develop some physiological and genetic understanding of the trait, apply classical breeding approaches to develop germplasm expressing the trait, and a simulation analysis across the USA to identify where, how often, and how much the trait in soybean will benefit farmers. The research on the limited-transpiration trait has now led to higher yielding commercial germplasm for water-deficit environments based on expression of the limited-transpiration trait. As often suggested but rarely put into practice, a multi-level, multi-faceted approach was applied in the study of the limited-transpiration trait to generate scientific understanding that was applied in crop breeding to generate higher yielding genotypes.