The present study evaluated submergence responses in 88 lowland indigenous rice (Oryza sativa L.) landraces from Koraput, India, to identify submergence-tolerant rice genotypes. In pot experiments, variations in survival rate, shoot elongation, relative growth index, dry matter, chlorophyll, soluble sugar and starch contents were evaluated in two consecutive years under well-drained and completely submerged conditions. Principal component analysis showed that the first three axes contributed 96.820% of the total variation among the landraces, indicating wide variation between genotypes. Major traits such as survival rate, relative growth index, soluble sugar and starch contents appeared to be important determinants of phenotypic diversity among the landraces. Phenotypic coefficient of variance was higher than genotypic coefficient of variance for all the traits and all showed high heritability (90.38%–99.54%). Five rice landraces (Samudrabali, Basnamundi, Gadaba, Surudaka and Dokarakuji) were the most tolerant to submergence. When submerged for up to 14 d, Samudrabali, Basnamundi and Godoba were notable for having greater survival rates than a standard submergence tolerant variety FR13A, and also notable for elongating more vigorously and accumulating more biomass. These three landraces may therefore be especially useful in lowland rice growing areas that are affected by both moderate stagnant water and flash flooding. Molecular genotyping revealed that the submergence tolerance of Samudrabali, Basnamundi and Godoba is linked to the presence of one or more different Sub1 loci and it may well prove useful for breeding improved submergence tolerant rice varieties, thereby assising to improve yield stability in the rainfed lowland agro-ecosystem.

本研究评价了88种低地土著稻（Oryza sativa）的淹没响应。L.）来自印度科拉普特的地方品种，以鉴定耐淹水水稻基因型。在盆栽实验中，在排水良好且完全淹没的条件下，连续两年评估了成活率，枝条伸长率，相对生长指数，干物质，叶绿素，可溶性糖和淀粉含量的变化。主成分分析表明，前三个轴贡献了地方品种间总变异的96.820％，表明基因型之间的变异很大。存活率，相对生长指数，可溶性糖和淀粉含量等主要特征似乎是地方品种表型多样性的重要决定因素。所有性状的表型变异系数均高于基因型变异系数，且均显示出较高的遗传力（90.38％–99.54％）。五种水稻地方品种（Samudrabali，Basnamundi，Gadaba，Surudaka和Dokarakuji）对浸水的耐受性最高。当沉没达14 d时，萨穆德拉巴利（Samudrabali），巴斯南蒙迪（Basnamundi）和戈多巴（Godoba）具有比标准的耐淹水品种FR13A更高的存活率，并且还具有更强的伸长能力和更多的生物量。因此，这三个地方品种在受中等程度的积水和山洪影响的低地水稻种植地区可能特别有用。分子基因分型显示，Samudrabali，Basnamundi和Godoba的浸水耐受性与一种或多种不同的存在有关 Basnamundi和Godoba以比标准的耐淹水品种FR13A更高的存活率而著称，还以更大的伸长率和更多的生物量而著称。因此，这三个地方品种在受中等程度的积水和山洪影响的低地水稻种植地区可能特别有用。分子基因分型显示，Samudrabali，Basnamundi和Godoba的浸水耐受性与一种或多种不同的存在有关 Basnamundi和Godoba以比标准的耐淹水品种FR13A更高的存活率而著称，还以更大的伸长率和更多的生物量而著称。因此，这三个地方品种在受中等程度的积水和山洪影响的低地水稻种植地区可能特别有用。分子基因分型显示，Samudrabali，Basnamundi和Godoba的浸水耐受性与一种或多种不同的存在有关Sub1基因座及其可能很好地证明可用于育种改良的耐淹水水稻品种，从而提高雨养低地农业生态系统的产量稳定性。