Further Information on the Genetic Variation of Indigenous Rice Varieties in Yunnan Province, China.

Abstract

Yunnan province in China is located in the center of genetic diversity of cultivated rice, an area which in-cludes East Nepal, Bhutan, Assam in India. Myanmar, Laos and Northern Thailand (Chang, 1976; Nakagahra and Hayashi, 1977). Several studies on genetic variation and differentiation of the Yunnan rice varieties based on isozyme analyses (Hu et al., 1981; Nakagahra, 1984; Zhu et al., 1984; Xiong et al., 1987; Nagamine et al., 1992) have been conducted, indicating that allelic varia-tions at the isozyme loci increase from north to south in the province and that genetic diversity is the highest in the varieties from the southern and/or southwestern re-gions of the province. Geographically, this region is bordered by Myanmar. Laos and Vietnam and is located in the northeastern part of the center of genetic di-versity for cultivated rice. However, the sampling sites of the varieties used in previous reports were apparent-ly rather limited; the materials from the northern region of the province were particularly scarce. To reconfirm that the rice varieties from the southern or southwest-ern region in the province show the highest genetic di-versity, a larger number of indigenous varieties, collected from almost all counties in the province, were analyzed for isozyme variation at the county level.