Abstract
Dehydration tolerant QTLs at the seedling stage in rice (Oryza sativa L.) was studied using green shoot length as a parameter, which was measured during the recovery period after dehydration stress. According to the results of pilot experiment carried out to evaluate the two parental rice cultivars for the level of dehydration tolerance, at 4 - day and 5-day dehydration stress, Japonica parent Hyogokithanishiki (HGKN) showed more tolerance than that of Hokuriku-142 Indica parent (HOK). Quantitative trait loci (QTLs) associated with dehydration tolerance was identified using 163 recombinant inbred lines derived from these parents on a linkage map constructed with 95 simple sequence repeat (SSR) markers. Three dehydration tolerant minor QTLs were identified on chromosome 1, 2 and 3 at composite interval mapping by WinQTLCARTOGRAHER. According to the additive effect plots the QTLs on chromosome 1 and 2 have the allelic effect from the Indica parent Hokuriku-142 and QTL on chro- mosome 3 has allelic effect from Hyogokithanishiki Japonica parent. However, according to the 1000 time permutation test, these QTLs didn’t exceed the threshold LOD value. Tropical Agricultural Research and Extension 15(4): 2012: page 98-104
Highlights
Drought stress is the most common adverse environmental condition that can seriously reduce crop productivity
Development of new rice cultivars with drought tolerance saves a great amount of water and helps to increase yield stability
F6 generation of 163 recombinant inbred line (RIL) population derived from Japonica rice cultivar, Hyogo-Kithanishiki (HGKN), and an Indica rice cultivar, Hokuriku-142 (HOK) were used for QTL analysis
Summary
Drought stress is the most common adverse environmental condition that can seriously reduce crop productivity. Increasing crop resistance to drought stress would be the most economical approach to improve agricultural productivity and to reduce agricultural use of fresh water resources. It is difficult to conduct drought stress treatments in a quantitative and reproducible way. These difficulties have significantly impeded research on plant drought tolerance. Limited awareness of plant phenotypes conferred by drought stress has prevented researchers from using traditional genetics approaches to directly study drought stress tolerance (Tripathy et al 2000). Undisclosed drought tolerance mechanism has stagnated both traditional breeding efforts and use of modern genetics approaches in the improvement of drought tolerance of crop plants (Passioura 2010; Sinclair 2011). Despite the lack of understanding of drought tolerance mechanisms, physiological and mo-
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