Classification of rice varieties by diriscminant functions Phylogenetic differentiation of the cultivated rice, XIV.

Abstract

Based on the study of chalacter assoilation among rice varieties collected from different Asian countries, one of the writer(OKA 1953) formerly pointed out that the varieties could bc classified into two groups, "Contlnental " and "Insular " (so named in accordance with geographical distribution but largely corres, ponding to the s.o-called Indica and Japonica t-ypes, ), and that the latter could be subdivided into two minor proups (" Tropical-Insular " and "Ternperate-Insular"), but the variation appeared to be continuous because of the presence of intermediate varieties. In order to illustrate the pattern of this variation more clearly, varieties appearing to be repres, entatives of the "Continental", " Tropical-Insular " and "Temperate-Insular " groups, their numbers being 40, 23 and 15 respectively, were chosen, and discrirtlinant functions for maximanizing the difference between variety-groups were computed using measurements on nine different characters (1. KCIO3 resis, tance, 2. Iow temperature resistance, 3. drought resistance, 4. days of germination, 5. weight for shedding, 6. length-width ratio of grain, 7.. Iength of apiculus hair, 8. Iength of awn, and 9. degree of destruction of endos, perm in KOH solution ; the same data as used in the first paper of this, series).'The method described by MATHER and PHILP (1949) was used.