Pedigree analysis of nationally approved soybean cultivars from 1984 to 2013 and implications for breeding

摘要

To reveal origins of 316 state authorized varieties from 1984 to 2013, rules of their parents' selection including types and hybrid configurations of direct parents, geo-graphical sources and types of their ancestors were analyzed. Various important direct parents and ancestors were summarized and nuclear contribution of ancestors was also estimated by pedigree analysis. Among 316 registered cultivars, 298 (94.3%) were bred by hybridization, and most of their direct parents were cultivars or breeding lines (65.5%). Cultivars and breeding lines were mostly used as female parents, with 53.0% and 38.7%respectively. The 316 released cultivars were traced to 373 final ancestors, mainly com-posed of landraces (55.5%) and breeding lines (36.7%). The 373 final ancestors came from different regions, including 121 from northern area, 110 from Huang-Huai-Hai area, 53 from southern area and 76 from abroad. These ancestors were mainly from the same ecologic zone as the approved cultivars. Newly approved cultivars always have more ancestors and a broader genetic base. However, distribution of these ancestors was unbalanced, and a few ancestors provided significant genetic contributions to later generations, such as the most concentrated final ancestors from Huang-Huai-Hai region followed by northern and southern regions. These results offer more information regarding their important parents and provide valuable references to soybean breeding. We should increase soybean ger-mplasm exchanges with different regions and make use of elite lines, foreign cultivars and wild soybean germplasm to broaden the genetic background.