Breeding for next-generation biotic stress-tolerant pigeonpea for sustainable food legume production

Pigeonpea, scientifically known as Cajanus cajan (L.) Millsp, is an important leguminous crop grown in tropical and subtropical areas. However, its production is increasingly threatened by biotic stresses, including sterility mosaic disease (SMD), fusarium wilt (FW), Helicoverpa armigera, Maruca vitrata, and other emerging plant pathogens, posing significant challenges to its sustainability. The pigeonpea gene pool exhibits considerable genetic diversity for biotic stress resistance, offering potential for developing resistant cultivars. The establishment of well-defined core and mini-core collections simplifies the breeding process by providing easier access to genetic diversity and facilitating the development of resistance to biotic stresses. The availability of a draft genome sequence in the databases, along with extensive marker resources, has steered research toward trait mapping for disease resistance. These genomic resources have provided valuable insights into the pigeonpea genome, enabling precise and efficient solutions to production constraints. Despite these resources and the genetic variability within the gene pool, much of it remains untapped and underutilized in breeding programs aimed at enhancing disease resistance in pigeonpea. Modern genomic tools such as next-generation sequencing, haplotype-based breeding, and genome-wide selection are enhancing selection efficiency and driving next-generation breeding-a crucial step in the genetic improvement of pigeonpea. Breeding for biotic stress tolerance can greatly benefit from molecular markers and the identification of candidate genes associated with resistance mechanisms. Furthermore, the development and scrutiny of extensive repositories of fusarium wilt (FW)-responsive genetic material and advanced expressed sequence tags (ESTs) further enrich the genomic resources available for pigeonpea research.This review highlights the ongoing genetic improvement of pigeonpea by integrating conventional breeding with genomic research, highlighting the synergistic approach to addressing biotic stress challenges.