Genomics-assisted breeding for improving stress tolerance of graminaceous crops to biotic and abiotic stresses: Progress and prospects

Abstract

Advances in genomics research have led to the development of high-quality reference genome data, genome-wide molecular markers, quantitative trait loci (QTL), and high-throughput genotyping platforms for cereal crops. The availability of these genomic resources has facilitated the development of breeding technologies such as genomics-assisted breeding (GAB). GAB is an advanced form of marker-assisted breeding where genome-wide genetic selection and high-density genotyping are performed to generate elite varieties with better agronomic traits. Marker-assisted selection (MAS) is a genotypic variation based indirect selection method that reduces the time and cost of breeding. The different approaches of MAS include marker-assisted backcrossing (MABC) or introgression of agronomically important alleles or QTLs with relatively large effect, marker-assisted recurrent selection (MARS) for introduction of complex traits and genomic selection (GS) based on overall molecular markers distributed throughout the genome. In view of these, the present chapter discusses the application of genetic and genomic resources in identification and mapping of stress-tolerant genes/QTLs and their application in molecular breeding. In addition, the chapter also summarizes the current status of marker-assisted selection approach for improving tolerance to drought and virus infection in major graminaceous crops. The challenges and future prospects of GAB in enhancing crop productivity under stress conditions have also been summarized.