Studies on the soybean varieties in Korea -1. Classificiatons of Ecotypes and Maturity groups-

대두의 품종에 관한 연구 -제1보 생태형과 성숙군의 분류-

Experiments were carried out to classify the ecotypes and maturity groups of soybean varieties, and to make clear the relationships among these ecotypes, maturity groups and some characteristics in the growing and ripening process of soybean varieties in Korea. Soybean varieties used as the material were 138, 57 varieties collected from Japan, America and Canada and 81 local varieties of Korea. These varieties were grown in the Experimental Farms, College of Agriculture, Seoul National University, Suwon, Korea and Chinju Agricultural College, Kyungsang Namdo, Korea. Seed sowing was conducted at 8 times from April15 to July 29, at 15 day-intervals, in 1962. The classification methods of ecotypes and maturity groups applied in this study, and the results obtained are summarized as follows; 1. Ecotypes were classified from the standpoint of the periods from emergence to flowering, the shortened ratio of days from sowing to flowering by delayed sowing, and the periods from flowering to maturity(as shown in Table A). 2. All varieties wer classified into 10 ecotypes of Ia$_1$, Ib$_1$, IIa$_2$, IIb$_1$, IIb$_2$, IIIb$_1$IIIb$_2$, IIIc$_1$and IIIc$_2$ symbols. Korean local varieties, however, belong to 6 ecotypes of IIb$_1$, IIb$_2$, IIIb$_1$, IIIc$_2$, IIIc$_1$ and IIIc$_2$, respectively(table 1). 3. Durations from sowing to maturity were from 120 to 190 days in April sowing plots of all varieties. From the standpoint of the durations, maturity groups were classified into 9 groups from group I, extreme early, to group IX, extreme late, but our local varieties belong to 5 maturity groups of III, IV, V, VI and VII symbols, respectively(Table 2). 4. Kinds of ecotypes and maturity groups, and the number of soybean varieties belonging to those are as shown in Table B. 5. In this study, it was observed that there were some close relations between these ecotypes and maturity groups (Table 3,4), and among the ecotypes, maturity groups and some other characteristics in the growing and ripening process of the soybean varieties(Table 5). 6. Furthermore, it was also observed that the kinds of ecotypes and maturity groups of recommended varieties in the southern Korean provinces are more numerous than those of the northern provinces in Korea.