小麦苗期抗旱相关形态指标的灰色关联度分析

为了系统研究小麦苗期形态指标与抗旱性的关系并筛选有效的抗旱性指标,使用PEG-6000模拟干旱胁迫,采用灰色关联度分析法分析了28份小麦品种苗期干旱胁迫下的苗高、最长根长、根数、地上部鲜重、地上部干重、根鲜重、根干重、叶片数、根冠比等9个形态指标与抗旱系数的关联程度,并以所得加权抗旱系数对各品种进行聚类分析.结果显示,各形态指标与抗旱系数的关联度依次为:叶片数(0.817)>苗高(0.766)>地上部干重(0.746)>地上部鲜重(0.729)>根数(0.699)>根干重(0.688)>根鲜重(0.681)>根冠比(0.645)>最长根长(0.399).研究还表明,9个形态指标可分为叶片相关因子、地上部生物量因子和根部生物量因子三大类,地上部生物量因子的关联度大于根部生物量因子;不能只通过差异显著度检验来判断某一指标是否可以用作抗旱性鉴定;聚类结果能较好地反映各小麦品种的地域分布.因此,进行小麦品种苗期抗旱性鉴定时,应加强对地上部形态指标的选择和鉴定,以提高选择效率.

Grey Correlation Analysis of Morphological Traits Related to Drought Tolerance of Wheat at Seedling Stage

This paper aims at probing the relationship between morphological traits and drought tolerance of wheat cultivars and screening effective indexes for drought resistance. A total of 9 morphological traits including plant height, main root length, root number, shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, leaf number , root/shoot ratio measured in 28 wheat cultivars grown at laboratory drought stress by PEG-6000, were analyzed using grey relational grade. At the same time, cultivars were classified by using clustering analysis base on weight drought-tolerance coefficient. Grey correlation degrees were calculated between each trait and its drought coefficient and ranked as follows: leaf number (0.817) >plant height (0.766) >shoot dry weight (0.746) >shoot fresh weight (0.729) >root number (0.699) >root dry weight (0.688) > root fresh weight (0.681) >root/shoot ratio (0.645) >main root length (0.399). The result showed that 9 morphological traits could be classified 3 categories. The cluster consequence reflected fundamentally the origin and area distribution of cultivars. The results suggested that the over-ground traits was the base and the root traits were second in the trait-based selection of drought tolerance to improve the screen efficiency.