广西黄瓜地方品种鉴定评价及遗传多样性分析

Identification,evaluation and genetic diversity analysis of local cucumber varieties from Guangxi

【目的】鉴定评价广西黄瓜地方品种的农艺性状,并进行遗传多样性分析,筛选出具有潜力的地方品种,为我国南方黄瓜育种提供亲本材料。【方法】从广西各地区收集10个黄瓜地方品种,利用相关性分析、主成分分析和聚类分析等方法对其19个质量性状和8个数量性状进行鉴定评价及遗传多样性分析。【结果】10个广西黄瓜地方品种在各性状上存在明显差异,其中,8个数量性状的平均变异系数(20.4653%)较19个质量性状(45.8433%)低,但平均多样性指数(1.5943)较质量性状(1.0265)高。19个质量性状中,以瓜棱的变异系数最高,其次为种瓜裂纹类型和瓜刺色;以叶形的遗传多样性指数最高,其次为瓜形和瓜刺色。8个数量性状中,以单瓜重的变异系数最高,其次为瓜肉硬度和瓜长;以瓜肉厚和瓜肉硬度遗传多样性指数最高。27个农艺性状中,除瓜长与其他指标均不存在显著相关(P>0.05)外,其他性状间存在极显著(P<0.01)或显著(P<0.05,下同)相关性,其中单瓜重与瓜肉厚和瓜横径呈显著正相关,说明提高黄瓜产量可从改良瓜肉厚、瓜横径等性状着手;瓜皮硬度与瓜肉硬度、叶色和种瓜皮色呈显著正相关,与瓜肉糖度呈显著负相关,表明口感脆嫩的黄瓜品种糖度相对较高。主成分分析结果显示,前8个主成分因子(PC1~PC8),包含23个农艺性状,累计贡献率达97.311%,表明这些性状是广西黄瓜地方品种鉴定与评价的主要指标。以遗传距离15为阈值,可将10个广西黄瓜地方品种被分为四大类群(Ⅰ~Ⅳ),各类群的数量性状和质量性状存在明显差异,虽然少部分来源于同一地区的种质资源分布在不同群类,但大部分种质的聚类结果与海拔高度和地理分布相关,其中第Ⅲ类包含白皮且无刺的黄瓜种质,可用来选育白皮品种;第Ⅳ类群属于大瓜形种质,具有较高丰产潜力。【结论】广西黄瓜地方品种具有丰富的遗传多样性,在瓜棱、瓜裂纹、种瓜斑纹和瓜刺色等性状方面具有较大的应用潜力,可为黄瓜育种提供优异的亲本材料。

【Objective】In order to screen out potential local varieties and provide parental materials for cucumber breeding in southern China,agronomic traits of the local cucumbers germplasm resources from Guangxi were identified and the genetic diversity was analyzed.【Method】Ten cucumber varieties were collected from various parts of Guangxi.By means of correlation analysis,principal component analysis and cluster analysis,identification and genetic diversity of 19 qualitative traits and 8 quantitative traits were studied.【Result】There were large differences between the 10 local cucumber resources in the traits,in which the mean coefficient of variation of 8 quantitative traits(20.4653%)was lower than those of 19 qualitative traits(45.8433%),but the average genetic diversity index of quantitative traits(1.5943)was higher than that of quality traits(1.0265).Among the 19 qualitative traits,the fruit ribbing was the highest in the coefficient of variation,followed by the fruit mottling and the color of spine.The leaf shape was the highest in genetic diversity index,followed by the fruit shape and the color of spine.Among the eight quantitative traits,the weight per fruit was the highest in the coefficient of variation,followed by fruit firmness and the fruit length,while the fruit flesh thickness and the fruit firmness was the highest in the genetic diversity index.The correlation analysis showed that some characters had significant correlation(P<0.05,the same below)or extremely significant correlation(P<0.01)with others among the 27 agronomic traits,except the fruit length(P>0.05).The weight per fruit was significantly positively correlated to fruit flesh thickness and fruit transverse diameter,which meant that cucumber yield could be improved from the thickness and fruit diameter improvement.The fruit basal firmness was significantly positively correlated to fruit firmness,leaf color and the color of fruit for seed harvest,while it was negatively correlated with the sugar content,which indicated that cucumber with crisp and tender taste had high sugar content.The results of main component analysis showed that the first eight main component factors(PC1-PC8)contained 23 agronomic traits,and the total contribution rate reached 97.311%,indicating that these agronomic traits were the main indicators for identification and evaluation of Guangxi local cucumber resources.Genetic distance 15 as the threshold,ten cucumber resources were divided into four groups(Ⅰ~Ⅳ),in which the quantitative traits and the qualitative traits were obvious difference.Although a small number of germplasm resources from the same area were distributed in different groups,the clustering results of most germplasm were related to the altitude and geographical distribution.Among them,the III group contained cucumber resources with white basal color and no spine,which might be used for the white fruit basal color variety breeding,and theⅣgroup contained big type cucumber,which could be applied to high-yield varieties breeding.【Conclusion】The cucumber germplasm resources in Guangxi performance rich genetic diversity,and the characters have great application potential such as fruit ribbing,cracking habit,color of fruit mottling,color of spine and so on.These resources can provide excellent parent material for cucumber breeding.