Genetic Diversity and Classification of Cytoplasm of Chinese Elite Foxtail Millet [ (L.) P. Beauv.] Germplasm

摘要

A single cytoplasmic source of foxtail millet male sterile lines has become a major limiting factor for wide utilization of heterosis in foxtail millet. To explore genetic diversity of Chinese foxtail millet cytoplasm, 23 pairs of mitochondrial DNA (mtDNA) primers that showed a high level of polymorphism among selected 14 genetically diverse foxtail millet accessions were identified after screening 34 pairs of consensus mtDNA primers that were derived from various plant species. The 23 pairs of primers were used to analyze genetic diversity of cytoplasm in 111 Chinese elite foxtail millet accessions. Genetic similarity coefficients for differentiation of cytoplasmic types were calculated based on the phylogenetic tree and female-parent-derived pedigree graph of all the tested accessions. The results show that the genetic diversity of foxtail millet cytoplasm is low, which makes Chinese foxtail millet germplasm vulnerable to the infection by cytoplasm-related diseases. The 111 tested accessions can be classified into eight cytoplasmic types: Qinyuanmujizui, Huangruangu, Riben60ri, Dahuanggu, Yingsuigu, Heizhigu, MissingI, and MissingII. The eight cytoplasmic types matched with the geographic and ecological distribution pattern of the most tested accessions. The results provided a scientific foundation for rationally utilizing these germplasm lines, diversifying cytoplasmic types in male sterile lines, and further improving hybrid foxtail millet cultivars.