对白菜型冬油菜F2群体主要生理生化特性的变化进行分析，利用陇油7号和陇油9号杂交得到103个F2单株，对越冬率、幼苗习性、超氧化物歧化酶（SOD）等8个指标进行调查、测定。对所得数据进行方差分析、聚类分析、相关分析、通径分析。结果表明，除SOD活性外，其余各指标在F2群体中呈连续变异，分布频率大致接近正态分布，同时存在双向超亲分离现象。在聚类距离为3．58处，F2群体分为8个类群，群体间具有较大的遗传差异。相关分析表明所有指标与越冬率均有显著或极显著相关。各生理生化指标对越冬率的通径系数与相关系数方向均一致，但通径系数更有利于解释其本质，通过通径分析得到各指标对白菜型冬油菜越冬率相对重要性从大到小的顺序是：幼苗习性，SOD活性，MDA含量，游离脯氨酸含量，POD活性，CAT 活性，可溶性蛋白含量。幼苗习性对越冬率主要是通过直接影响起作用，影响率达79．8％，CAT 活性对越冬率的影响主要是通过间接影响起作用的，间接影响率达68．7％，而其余各指标对越冬率的影响均是通过直接和间接影响共同起作用的。这些结果可为白菜型冬油菜数量性状抗寒基因定位分析提供有用的信息。%Overwintering rates,seedling habits,SOD activity,and five other physio-biochemical indicators in 103 F2 populations of a winter rapeseed (Brassicarapa)cross between Longyou 7 and Longyou 9 were studied using variance analysis,correlation analysis,cluster analysis and path analysis.The frequency of all indicators (except SOD)activity in the F2 populations was approximately normally distributed but with a slight skew.A tremendous transgressive segregation for all indicators was observed in the populations.At a cluster distance of 3.58,F2 populations were divided into eight groups,with great genetic differences.Correlation analysis showed that all indicators had significant differences in overwintering rates.The path coefficient and correlation coefficient between all indicators and overwintering rate were consistent,but the explanation of their relation-ships were better explained by the path coefficient.Through path analysis,the relative importance in descend-ing order of B. rapa winter survival rate was:Seedling habits,SOD activity,MDA content,free proline con-tent,POD activity,CAT activity,and soluble protein content.Seedling habits directly impacted winter surviv-al rates,and the influence reached 79.8%,but CAT activity was mainly through indirect effects and the indi-rect affect rate was 68.7%,with the rest of the indexes co-acting through both direct and indirect effects. These results provide useful information for quantitative trait loci (QTL)mapping.
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