A New PCR-Based Linkage Map in Pearl Millet

Pearl millet [Pennisetum glaucum (L.) R. Br.] is a multipurpose cereal grown for grain, stover, and green fodder. Relative to other cereal species, it ranks sixth in annual world production. Use of molecular marker technology for pearl millet genetic improvement has been limited because of an insufficiently developed linkage map. The majority of the pearl millet molecular markers (RFLP and SSR) mapped to date are clustered around the seven pearl millet chromosome centromeres, and only a few marker loci are mapped to more distal regions. There is a need for more evenly distributed markers throughout the linkage map and greater marker coverage of the gaps in earlier established maps. The objective of this research was to develop a PCR-based molecular marker linkage map for pearl millet on the basis of a recombinant inbred line (RIL) population resulting from a cross between lift 23DB and PI 536400. This mapping effort involved 152 RILs and 196 PCR-based DNA markers (66 SRAPs, 63 RAPDs, 27 ISSRs, 31 pearl millet, 6 sorghum, and 3 maize SSRs). The average genetic distance between markers was 9.2 cM, varying from 0 to 25.6 cM. The number of markers in each linkage group (LG) ranged from 6 to 35. The resulting map consisted of nine linkage groups that spanned about 1796 cM. The majority of the markers used in this study to construct the genetic linkage map were randomly distributed in each LG, which makes it useful in pearl millet mapping and breeding.