Realizing hybrids between the cultivated peanut (Arachis hypogaea L.) and its distantly related wild species using in situ embryo rescue technique

Abstract

Cross-incompatibility between peanut cultigen and species outside section Arachis, impedes the transfer of desirable traits such as high resistance, good quality and high productivity from incompatible species in cultivar development. To recover hybrids from 4 incompatible crosses involving 3 wild species, viz., A. pusilla Benth., A. appresipilla Krapov. & W.C. Greg. and A. paraguariensis Chodat & Hassl., an in situ embryo rescue technique was exploited, resulting in hybrid seeds from all the 4 crosses. The key of this technique is to apply growth substances to pollinated flower bases, and the next step is to wait and harvest seeds directly, whose hybridity is to be tested by miniature inverted-repeat transposable element markers. The technique is advantageous over its in vitro counterpart in earlier intervention, easier operation, and shorter duration required for obtaining hybrids. These superiorities warrant its wide use in the genus Arachis as well as in other plant taxa where post-zygotic hybridization barriers also exist.