Current Perspectives on Introgression Breeding in Food Legumes

Abstract

Food legumes are important for defeating malnutrition and sustaining agri-food systems globally. Breeding efforts in legume crops have been largely confined to the exploitation of genetic variation available within the primary genepool, resulting in narrow genetic base. Introgression as a breeding scheme has been remarkably successful for an array of inheritance and molecular studies in food legumes. Crop wild relatives (CWRs), landraces, and exotic germplasm offer great potential for introgression of novel variation not only to widen the genetic base of the elite genepool for continuous incremental gains over breeding cycles but also to discover the cryptic genetic variation hitherto unexpressed. CWRs also harbor positive quantitative trait loci (QTLs) for improving agronomic traits. However, for transferring polygenic traits, “specialized population concept” has been advocated for transferring QTLs from CWR into elite backgrounds. Recently, introgression breeding has been successful in developing improved cultivars in chickpea (Cicer arietinum), pigeonpea (Cajanus cajan), peanut (Arachis hypogaea), lentil (Lens culinaris), mungbean (Vigna radiata), urdbean (Vigna mungo), and common bean (Phaseolus vulgaris). Successful examples indicated that the usable genetic variation could be exploited by unleashing new gene recombination and hidden variability even in late filial generations. In mungbean alone, distant hybridization has been deployed to develop seven improved commercial cultivars, whereas in urdbean, three such cultivars have been reported. Similarly, in chickpea, three superior cultivars have been developed from crosses between C. arietinum and Cicer reticulatum. Pigeonpea has benefited the most where different cytoplasmic male sterility genes have been transferred from CWRs, whereas a number of disease-resistant germplasm have also been developed in Phaseolus. As vertical gene transfer has resulted in most of the useful gene introgressions of practical importance in food legumes, the horizontal gene transfer through transgenic technology, somatic hybridization, and, more recently, intragenesis also offer promise. The gains through introgression breeding are significant and underline the need of bringing it in the purview of mainstream breeding while deploying tools and techniques to increase the recombination rate in wide crosses and reduce the linkage drag. The resurgence of interest in introgression breeding needs to be capitalized for development of commercial food legume cultivars.

The performance of agronomic traits, genetic variability, and correlation studies for yield and its components in some red rice (Oryza sativa) promising lines

“…When combined with the heritability calculation, the genetic coefficient of variation would provide the best reference for the amount of advance predicted from the selection (Kumar et al 2017). Plant selection can be aided by correlation studies between yield and its contributing characters (Pratap et al 2020). The correlation coefficient may also be used to distinguish characters with little or no effect on rice yield.…”

Legume Breeding for the Agroecological Transition of Global Agri-Food Systems: A European Perspective

“…This can be remedied by a continuing infusion of genetic diversity coming from old varieties, landraces, ecotypes, or wild populations. However, legume breeding programs are relatively small, often forcing breeders to fulfill short-term breeding goals by using elite germplasm rather than “exotic” germplasm, which may require lengthy pre-breeding ( Dwivedi et al, 2016 ; Coyne et al, 2020 ; Pratap et al, 2021 ). This emphasizes the importance of pre-breeding programs carried out by public institutions that exploit landraces and wild relatives and make the resulting germplasm globally available.…”

An advanced lentil backcross population developed from a cross between Lens culinaris × L. ervoides for future disease resistance and genomic studies

“…Crop wild relatives have been used to improve the resistance and resilience of elite cultivars against various biotic and abiotic stresses in many crops (Hajjar and Hodgkin, 2007) including grain legumes (Pratap et al, 2021). (quaternary gene pool, see Wong et al, 2015).…”

“…Broadening the genetic base of breeding programs by introducing new genetic resources is required for development of improved lentil germplasm. Crop wild relatives have been used to improve the resistance and resilience of elite cultivars against various biotic and abiotic stresses in many crops (Hajjar and Hodgkin, 2007) including grain legumes (Pratap et al ., 2021).…”