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试验利用菲律宾旱季无雨的自然干旱条件,大田鉴定了192份水稻种质资源的苗期抗旱性。试验结果表明,水稻种质中存在大量的具有苗期抗旱性的品种。就所观察的三个性状:卷叶(leaf rolling,LeR),枯叶(leaf drying,LeD)及复水恢复(drought recovery rate,DRR)而言,11个水稻品种在卷叶性状(LeR)上,12个水稻品种在枯叶性状(LeD)上极显著优于抗旱性对照品种NSIC Rc 9,14个品种在复水恢复性状(DRR)上显著优于抗旱性对照品种NSIC Re 9。有的品种在两个,甚至3个性状上都比抗性对照显著,表明不同的品种可能采取不同的机制来适应干旱胁迫,如降低叶片面积,及早发深根等:同一抗旱机制也可以作用于不同的表型上,如渗透势调节(Osmoticadiustment)。3个性状间存在极显著的相关,其中LeD与DRR的相关性最高为0.821 62,其次为LeD与LeR为0.801 79和LeR与DRR为0.725 93。对抗旱性性状的选择最好使用田间筛选,因为大田筛选提供了性状表达的真实环境;卷叶,枯叶,和复水恢复能力作为苗期抗旱性指标能有效地筛选苗期抗旱性品种。
In the experiment, the drought-free natural drought conditions in the Philippines during the dry season were used to determine the seedling drought resistance of 192 rice germplasm resources. The results show that there are a large number of rice germplasm species with drought resistance at seedling stage. For the three traits observed, leaf rolling (LeR), leaf drying (LeD) and drought recovery rate (DRR) , 12 rice cultivars were significantly better than drought resistant cultivar NSIC Rc in leaf traits (LeD). 9 and 14 cultivars were significantly better than drought resistant cultivar NSIC Re 9 in DRR. Some species were significantly more resistant than the resistant ones in two or even three traits, indicating that different breeds may adopt different mechanisms to adapt to drought stress, such as reducing leaf area and early deep rooting. The same drought-resistance mechanism can also act On different phenotypes, such as Osmotic potential adjustment. There was a significant correlation between the three traits. The correlation between LeD and DRR was 0.821 62, followed by LeD and LeR was 0.801 79 and LeR and DRR was 0.72593. Field selection is the best choice for drought resistance traits because field screening provides a real environment for traits expression; leaf curling, dead leaves, and rehydration recovery ability as seedling drought resistance indicators can effectively screen the seedling drought-resistant varieties.