Molecular Breeding for Stay-Green: Progress and Challenges in Sorghum

This chapter focuses on the usage of stay-green as a breeding target under water-limited conditions. It reviews recent progress in different areas of stay-green research, with a particular focus on sorghum, where this trait has been most studied. Given the potential benefit of stay-green, genotypes displaying this trait have been used to identify the genomic regions responsible for this phenotype. Several quantitative trait loci (QTLs) have been identified, using different breeding populations and stay-green QTL donors, and different types of drought stress. The chapter reviews the experimental conditions in which phenotyping for stay-green has taken place and the different ways of assessing this phenotype, either from leaf senescence curves or leaf greenness assessments. It summarizes current work being done at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), in Andhra Pradesh, India to introgress several known QTLs for staygreen into various agronomically elite genetic backgrounds.