Introgression Breeding in Brassica juncea

Abstract

AbstractIntrogression breeding refers to the transfer of one or more genomic segments from one genome to another, usually between species, for crop improvement. Brassica juncea is a major vegetable and oilseed crop with a large number of close and distant relatives. Many of these relatives contain useful agronomic traits and can be hybridized with varying degrees of difficulty with B. juncea. Previously, introgression breeding in B. juncea (2n = AABB) has been successfully carried out to introduce novel genetic diversity and heterosis from progenitor diploid species B. rapa (2n = AA) and B. nigra (2n = BB) as well as closely related allotetraploids B. carinata (2n = BBCC) and B. napus (2n = AACC). Additional traits of agronomic importance have been introgressed from wider relatives such as Brassica fruticulosa, Erucastrum cardaminoides and Sinapis arvensis which do not share a genome in common with B. juncea, to produce B. juncea lines with resistance to mustard aphid, Sclerotinia disease and auxin herbicide. Several hybrid breeding systems (cytoplasmic male sterility plus fertility restorer lines) have also been developed via hybridization with species such as Moricandia arvensis, Trachystoma ballii and various Diplotaxis species. Introgression breeding can be challenging, but shows excellent potential for the introduction of highly valuable qualitative traits such as biotic stress resistances from wild relatives into B. juncea. In future, increasing accessibility and availability of resources such as genome sequences of wild relatives, allowing genotyping of early generation hybrids and development of genetic markers linked to specific traits, is expected to facilitate introgression breeding for crop improvement of B. juncea.KeywordsIntrogression breeding Brassica juncea Genetic diversityHybridizationResynthesis