Genetic Base of Korean Soybean Varieties Released from 1913 to 2002

Abstract

The genetic base was defined as the ancestral pool from which crop varieties were derived, and was used to characterize genetic diversity in crop breeding. Number of primary parents used between 1913 and 2002 in Korean soybean breeding programs was 65 and has been increased since 1950. The major genetic base of soybean varieties developed in Korea consisted of American introductions (52.2%), Japanese introductions (26.5%) and Korean local lines (21.3%). Recently, the contribution of Japanese introductions has been decreased, while that of Korean local lines has been increased as the diversification of soybean varieties was emphasized. The number of primary parents which contributed 50~80% of genetic base in soybean varieties increased and the resulted greater genetic diversity in recent years. The average number of primary parents per variety and average number of primary parent per pedigree of a variety increased from 0.79 and 1.4 before 1970 to 2.60 and 6.6 after 2000, respectively. While the genetic contribution of 20 primary parents to 97 Korean soybean varieties developed since 1913 was 51.4%, that of six primary parents, (Essex, Backmokjangyeup, Yukoo 3, Elf, Hill, and Jangdanbaekmok) was 24.1%. Yukoo 3 was the primary parent which used to develop 37 varieties, followed by Jangdanbaekmok, Backmokjangyeup, and Miyakishirome which contributed genetically to 35, 28, and 22 varieties, respectively. However, the degree of genetic contribution of the major six primary parents has been decreased in terms of per parent and accumulated contribution as more germplasms introduced in soybean breeding programs.