Primary Analysis of Drought Resistance Heredity and Physiological Mechanism of Introgression Lines of Common Wild Rice(O.rufipogon Griff.) from Dongxiang in Jiangxi Province at Seedling Stage

With the repeated natural drought method and the 20%(w/v) PEG-6000 simulated drought method,the drought resistance of seedlings of a BIL population(BC1F9) of Dongxiang common wild rice(Dwr)/Xieqingzao B(Xqz B)//Xqz B were examined by drought treatment assay and genetic analysis.The control materials included the strong drought-resistant varieties,Brazil upland rice,Dongxiang common wild rice and the drought-sensitive cultivar Xqz B,using grade of drought resistance based on seedling wilting as evaluation indice.The result showed that after two repeated natural droughts and recovering growth in 1/2MS nutrient solution,the mean grades of drought resistance of 230 BC1F9 BIL population were 3.76 and 4.39,respectively.The continuous normal distribution of wilting rates suggested that drought resistance at the seedling stage in Dwr indicated the inheritance of qualitative-quantitative traits.The lines with 1~2 grades of drought resistance under natural drought were further treated with the stress of 20%(w/v) PEG-6000 simulated drought.The lines 1112,1168,1172 and 1315 were of strong drought resistance and can be further used for exploring and utilizing of drought resistance genes.Under 20%(w/v) PEG-6000 simulated drought stress,increases in the soluble sugar,proline content and SOD activity in the strong drought resistance line 1112 were larger than those in the weak drought resistant line 1323.Decreases in GSH content were smaller than in weak drought resistance lines,indicating that penetration materials were accumulated more rapidly and increased more in strong drought resistance lines than in weak drought resistance lines.And the accumulation of membrane peroxidation was slower,better for adaption to drought environment.