Collection, classification, and conservation of cultivatedand wild rices of the Lao PDR


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Abstract

The Lao People's Democratic Republic (Lao PDR) lies within the center of domestication of Asian rice (Oryza sativa L.). Many traditional varieties are grown in the rainfed lowland and rainfed upland ecosystems, but there is a danger of genetic erosion, particularly in the lowlands, as farmers adopt improved varieties. The Lao Ministry of Agriculture and Forestry (MAF) and the International Rice Research Institute (IRRI) jointly explored most of the rice growing areas between October 1995 and April 2000 and collected 13192 samples of cultivated rice, and 237 samples of six wild rice species. Cultivated samples were classified according to ecosystem, endosperm type and maturity. The numbers of samples collected from the northern, central and southern regions were 5915 (44.8%), 4625 (35.1%) and 2652 (20.1%) respectively. More samples (55.9%) were collected from the uplands than from lowland sites. Most samples (85.5%) had glutinous endosperm. Almost half the samples were medium maturing (47.1%), with approximately an equal number of early and late maturing forms. Apart from some localized areas where accessibility was restricted, the collection is representative of the rice genetic resources of the whole country. A genebank for medium-term storage was established near Vientiane. For long-term conservation, duplicate samples were sent to the International Rice Genebank at IRRI in the Philippines.

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