Genetic diversity in wild and cultivated peanut

Abstract

Narrow genetic diversity and a deficiency of polymorphic DNA markers have hindered genetic mapping and the application of genomics and molecular breeding approaches in cultivated peanut (Arachis hypogaea L.). We developed and mined genome survey sequences (GSSs) and a peanut EST database, assessed the frequency of polymorphic SSRs, and initiated the development of several hundred SSR markers with the goal of breaking the DNA marker bottleneck in cultivated peanut. Primers were designed and tested for a broad spectrum of SSR motifs and repeat lengths, and 97 GSS-based SSR, 59 EST-SSR, and 612 previously reported SSR markers were screened among diploid and tetraploid germplasm accessions. Population structures were resolved and allelic diversities were estimated among wild and cultivated peanut. The frequency of polymorphic SSRs is sufficient for developing a critical mass of DNA markers for genetic mapping and downstream molecular breeding applications in peanut.