The Value of Diploid Peanut Relatives for Breeding and Genomics

Abstract

ABSTRACTCollection, evaluation, and introgression research has been conducted with Arachis species for more than 60 years. Eighty species in the genus have been described and additional species will be named in the future. Extremely high levels of disease and insect resistances to immunity have been observed in many species of the genus as compared to the cultivated peanut, which makes them extremely important for crop improvement. Many thousands of interspecific hybrids have been produced in the genus, but introgression has been slow because of genomic incompatibilities and sterility of hybrids. Genomics research was initiated during the late 1980s to characterize species relationships and investigate more efficient methods to introgress genes from wild species to A. hypogaea. Relatively low density genetic maps have been created from inter- and intra-specific crosses, several of which have placed disease resistance genes into limited linkage groups. Of particular interest is associating molecular markers with traits of interest to enhance breeding for disease and insect resistances. Only recently have sufficiently large numbers of markers become available to effectively conduct marker assisted breeding in peanut. Future analyses of the diploid ancestors of the cultivated peanut, A. duranensis and A. ipaensis, will allow more detailed characterization of peanut genetics and the effects of Arachis species alleles on agronomic traits. Extensive efforts are being made to create populations for genomic analyses of peanut, and introgression of genes from wild to cultivated genotypes should become more efficient in the near future.