Genetic and genomic resources for accelerating marker-assisted ideotype breeding in pigeonpea ( <i>Cajanus cajan</i> L. Millsp.)

Pigeonpea (Cajanus cajan L. Millsp.) is a grain legume crop that is crucial for food and nutrition security in the sub-tropical regions of Asia and Africa. However, its production is constrained by undesirable varietal features and susceptibility to biotic and abiotic stresses. There is an urgent need to develop pigeonpea varieties with ideotype combining traits needed by the stakeholders. Landraces and wild relatives of pigeonpea are rich source of genes for genetic advance towards the desired ideotype. Pigeonpea genome and extensive transcriptome data required for gene discovery are available. Simple sequence repeat and single nucleotide polymorphism marker assays have been designed and used in mapping of genes and quantitative trait loci for key traits, but these need to be validated and utilized in breeding. Pigeonpea genetically modified for pod borer resistance is awaiting regulatory approval, and the power of genome editing is poised to be harnessed. Marker-assisted selection is still not a practical reality in pigeonpea, but mapping studies position the crop for future breakthroughs. Marker-assisted selection is expected to play a greater role in accelerating pigeonpea ideotype breeding. This review provides a comprehensive account of stakeholder preferences of varietal traits and genetic and genomic resources to help devise molecular breeding strategies for pigeonpea.