甜瓜种质幼苗期主要性状的变异性及主成分和聚类分析

Principal component and cluster analysis on variabilities of main characters at seedling stages of melon

为了给甜瓜杂交育种亲本的早期选择提供理论依据,选择有代表性的20份种质为材料,统计了幼苗期10个主要性状的变异性,并对其进行了主成分和聚类分析。结果表明,株高、最大叶宽、地上鲜质量、根鲜质量、地上干质量、壮苗指数等7个性状的变异系数较大,在21.45%~51.15%之间;利用主成分分析将10个性状指标转化为4个综合指标,其累积贡献率达84.76%,主成分综合分值排序结果显示,PV03、PV13、PV08、PV17、PV04分别占供试种质资源的前5位;以综合成分中主要因子为指标进行聚类分析,可将20份甜瓜种质分为5类,各类间幼苗长势和健壮程度有较大差异。因此,单从甜瓜幼苗主要性状的角度考虑,7个变异较大的性状指标是今后亲本材料改良的重点,排在前5位的材料综合性状表现优良,是培育壮苗配制杂交亲本的首要选择;聚于第Ⅳ类的种质可直接被利用,根据育种目标的不同,可对第Ⅰ、Ⅱ、Ⅴ类种质改良后再利用。

In order to offer reference for early selection of hybrid parents, using 20 typical melon gerrnplasms as materials, 10 main traits of the seedling period were studied for variability, principal component analysis and clustering analysis. The results showed that the wide variation existed among the variability of plant height, maximum leaf width, above-ground fresh weight, root fresh weight, above-ground dry weight and healthy seedling index, the variation coefficient of them was between 21.45% and 51.15%, and that 10 seedling traits were classified into 4 components with their cumulative contribution of 84.76% by principal component analysis, and the synthesis score of PV03, PV13, PV08, PV17, PV04 was the first five leading in 20 germplasms. Based on the results of principal component analysis, the 20 melon germplasms were divided into 4 groups with clustering analysis, among which there were obvious differences in the growth vigor and robust degree of seedling. Therefore, according to the above results, the 7 indexes of wider variation would be screened in the process of breeding in the future, and the first 5 leading cultivars could be preferred to select in practical production. The germplasms of group IV classed could be utilized directly, and ones of group Ⅰ, Ⅱ, Ⅴ could be improved in gene at frist and then used according to breeding objective.