主成分累计贡献率和性状选择对苦瓜遗传距离与产量杂种优势关系的影响

将9个苦瓜高世代自交系分成两组,按不完全双列杂交设计配制18个杂交组合。以茎粗、叶长、节间长、第一雌花节位、播种-始花天数和冷害指数等6个反映苦瓜植株形态、熟性和生态适应性的性状为基础性状组,当构成遗传相关系数矩阵的性状数目依次从6个增加到1 2个时,7组遗传距离在累计贡献率70%~95%内表现稳定,累计贡献率大于95%时表现不稳定。遗传距离与产量杂种优势之间的相关系数在7个和8个性状时最大,随性状数目增加,相关系数减小。对7个和8个性状在主成分累计贡献率70%~85%时的遗传距离与产量杂种优势之间的关系进行了线性回归分析,回归方程分别为Y=0.1293 0.0284X和Y=0.1867 0.0324X,均达到极显著水平。

Effect of principal component accumulative ratio of contribution and character selection on relationship between genetic distance and heterosis in bitter gourd (Momordica charantica L.)

Nine self-lines of bitter gourd were divided into two groups and 18 crosses were made by incomplete diallel cross.Stem width,leaf length,node length,the node of 1st female flower,seeding-flowering days and chilling injury index which involve plant morphology,maturity and ecological adaptation were selected for basic characters.7 groups of genetic distances which principal component accumulative contribution ratio vary from 70% to 95% were stable when character number which constitute genetic correlation coefficient matrix increased from 6 to 12.However,7 groups of genetic distances which principal component accumulative contribution ratio vary from 95% to 100% were unstable.The biggest correlation coefficient between genetic distance and heterosis occured when character number was 7 or 8.Then correlation coefficient became more and more smaller when character number added.Genetic distances were calculated by using 7 and 8 quantitative characters which principal component accumulative ratio contribution vary from 70% to 85%.Using genetic distance as independent variable and heterosis as dependent variable,regressing analyses were carried out.The results showed that there was a very significant linear relationship between genetic distance and yield heterosis and their regression equations were Y=0.1293 0.0284X and Y=0.1867 0.0324X,respectively.