不同基因型油菜对苗期水分胁迫的生理响应

通过盆栽试验分析了17个不同基因型甘蓝型油菜对苗期水分胁迫的生理响应及抗旱性差异。结果表明，水分胁迫下不同油菜材料9个生理生化指标的抗旱系数（Dc）存在显著差异，其中叶片萎蔫指数（WI）的变异系数和改良潜力最大。17份材料的平均隶属函数值（AS）变幅在0.12～0.94之间。相关分析表明AS与9个生理生化指标达显著或极显著相关，其中相关性最高的是WI和叶绿素含量，而且WI还与其余的8个生理生化指标具有很高的相关性。利用隶属函数法和系统聚类法对供试材料的抗旱性进行了评价分级，发现两种分类方法的评价结果一致，均可将供试油菜材料划分为不抗、低抗、中抗和高抗4种类型。鉴定获得了华杂10号、B108、Q2和中双7号等4份高度抗旱材料（AS > 0.75）。由于WI与苗期综合抗旱性高度相关，且测定简便，因此叶片萎蔫指数可作为油菜苗期抗旱性鉴定的关键指标。

Differences in physiological responses of Brassica napus genotypes under water stress during seedling stage

Pot experiments were carried out to study the physiological responses and drought resistance variations in 17 rapeseed genotypes.The results showed that rapeseed genotypes had significant different responses to drought stress as indicating by 9 physiological characteristics.Leaf wilting index(WI) has the largest values for coefficient of variation and improvement potential.Average subordinate function(AS) values for 17 genotypes ranged from 0.12 to 0.94.The AS was significantly correlated with 9 physiological characteristics(especially WI and chlorophyll content).In addition,WI was closely associated with other eight physiological indexes.By using either subordinate function or clustering analysis,17 tested rapeseed genotypes could be classified into 4 distinct groups(i.e.no resistance to drought,low resistance to drought,medium resistance to drought,and high resistance to drought),and four genotypes(i.e.Huayouza 10,B108,Q2 and Zhongshuang 7) were identified as highly tolerant to drought stress with AS>0.75.These genotypes could be used in drought breeding program.WI was recommended as a key index for drought resistance screening at seedling stage,in that it was highly correlated with all other AS and was very easy to measure.