Title: Expansion of an Improved Variety into Rain-fed Rice Cultivation in Northeast Thailand
Abstract: Indigenous glutinous rice varieties have recently been replaced with an improved variety, RD6, in Northeast Thailand. The good cooking quality and high yielding ability of RD6 have induced many farmers to plant it in their paddy fields. Productivity per planted field in the surveyed village has increased due to the planting of RD6 as well as the adoption of power tillers, subsidiary irrigation and fertilizers. This variety, a panicle-number type, tends to increase yields more easily than the old varieties when planted densely in the appropriate season with judicious fertilizer management under conditions of no drought and no inundation. Nevertheless, the instability of rice production caused by flood and drought is yet to be resolved in rain-fed cultivation. Planting RD6 in an unsuitable area normally fails to produce a good harvest. More improved varieties for rain-fed cultivation should be released in this region. I Introduction Since the release of the semi-dwarf high-yielding rice variety IR8 by the International Rice Research Institute in 1965, modern improved rice varieties have expanded to cover 74% of the rice-growing area in South and Southeast Asia [International Rice Research Institute 1993J. Most of these varieties have short culms and are non-photosensitive, which result in a high yield response to appropriate fertilizers in irrigated paddy fields. Despite the success of the improved varieties in irrigated areas, however, these character istics of the rice plant are said to hinder the spread of these varieties in rain-fed rice-cultivation areas. Because there is no regulation of water in paddy fields, such short rice plants are damaged by deep waterlogging; and at times of water shortage, fertilizer dressing enhances drought damage. For these reasons, the fear of crop failure has discouraged farmers from investment in seed and chemical fertilizers for semi-dwarf high-yielding varieties in rain-fed rice-cultivation areas. Although the area of irrigable paddy land in South and Southeast Asia is estimated as 20% of the total paddy area, modern varieties now cover more than this proportion. This means that modern varieties are planted in the adverse areas for rice growing, like rain-fed paddy fields. This is the situation in rice-growing areas in Northeast Thailand.
Publication Year: 1995
Publication Date: 1995-09-01
Language: en
Type: article
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Cited By Count: 8
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