Phylogenetic Differentiation of the Cultivated Rice Plant Ⅰ. Varietal Variations of Various Characters.

稻系统发生的分化Ⅰ.形質不同品種間之變異

H. Oka ； Y. C. Lu ； K. H. Tsai

《中華農業研究》 2卷3期 (1951/09) Pp. 1-31

https://doi.org/10.29951/JARC.195109.0001

並列摘要

1. The aim of the present study is to gain informations as to whether definite kinds of genic constitutions would be preponderant or not among the varieties of rice plant and, how the varieties are to be divided into groups. More than one hundred and twenty varieties picked out nearly randomly from numerous varieties of various districts of Eactern Asia were observed with respect to diverse characters, and on the ground of those results, discontinuity of varietal variation, intervarietal correlations and tendencies in character combination were investigated.
2. Besides phenol reaction which was found to he determined by a single genic change, the following several characters in which a number of genes would be concerned. i. e. pottasium chlorate resistance, low temperature resistance, drought resistance and the length of awn, showed discontinuous sppearances of varietal, variation by which the varieties were to be divided into two groups. Varietal variations of the days of germination, and the weight of grain shedding seemed somewhat to b disrontinuous. The degree of destruction of endosperm by caustic potash (alkali-test), the days of endosperm maturation, the length-width ratio of unhulled rice, the length of first and second internodos grown in a dark place, showed continuous appearance of varietal variation.
3. With regard to a greater part of these characters, except the length-width ratio of unhulled rice and length of the first and second internodes, the varieties positive in phenol reaction and the negative varieties showed characteristics contrary to each other. At the same time these characters were found to be correlated inter Se.
4. With regard to each of the five characters which showed discontinuous appearance of varietal variation, i.e. phenol reaction, pottasium chlorate resistance, low temperature resistance, drought resistance, and the length of awn, the used varieties were divided into two groups, plus and minus; and thus the characteristics of a variety was represented by a combination of five signs. Then, the frequency of varieties possessing respective kinds of character combination was investigated. Consequently, two definite kinds of character combination, namely, phenol reaction: plus, pottasium chlorate resistance and low temperature resistance: minus (weak), drought resistance: plus (hard), and awn: minus (awnless), and a character combination contrary in each to the above, were found to be preponderant among the used varieties.
5. Varieties possessing the former character combination phenol reaction: plus, etc) were found mostly among the varieties of Asiatic Continent, viz. China, Indo-china and India, while varieties possessing the latter one were found to distribute mainly over the islands of Western Pacific, viz. Sunda Islands, Celebes, Philippine, Formosa (Horai and the native varieties of mountain part) and Japan, in addition to northern China.
6. It was considered, on the ground of various facts as mentioned above, that the varieties of rice plant were to be divided into two variety-groups which were different in various characters, reserving some indistinct varieties which would belong to neither of them. These two variety-groups were named, with a view to manifest the tendency of geographical distribution, as ”Continental” and ”Insular” variety-groups.
7. Within Insular group, intervarietal correlations were found among such characters as follows: the degree of destruction of endosperm by caustic potash, the length-width ratio of unhulled rice, the length of first internode, and others. Accordingly, varieties possessing definite kinds of character combination were found to be preponderant. It was considered, therefore, that Insular variety-group could be divided into two minor groups, though the distinction being not so evident. These minor groups were named as ”Tropical insular” and ”Temperate Insular” variety-groups according to the tendency of geographical distribution.