Genetic Erosion from Modern Varieties into Traditional Upland Rice Cultivars (Oryza sativa L.) in Northern Thailand
2006
Ishikawa, R. | Yamanaka, S. | Fukuta, Y. | Chitrakon, S. | Bounphanousay, C. | Kanyavong, K. | Tang, L.H. | Nakamura, I. | Satō, Tōru | Sato, Y.I.
The purpose of this study was to assess the extent of genetic erosion of traditional upland germplasm in northern Thailand as a result of gene-flow from distinct strains carrying different genotypes. Even modern variety specific markers have not been developed, there is a comparative population in Laos. Thus, both populations were compared with various characters to evaluate gene-flow from modern variety to landraces. Glutinous and glabrous strains are predominated in Laos. However, such strains were drastically decreased in north-east Thailand. Gene diversity is higher in Thailand, compared to Laos at seven isozyme loci. This was a result of the higher frequencies of Indica strains and heterozygotes in Thailand. Plastid type was also determined by using an INDEL marker. Nearly half of Indica strains carried the Japonica plastid. Heterozygotes also tended to carry Japonica cytoplasm. Such nuclear-cytoplasm substituted strains and heterozygotes were probably generated by natural hybridization. Japonica strains tended to be a maternal donor rather than Indica ones. Or Indica strains would easily release pollens, which grow outside of upland fields.
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