部分杨梅种质资源表型性状多样性分析

Phenotypic traits diversity analysis of some Chinese bayberry germplasm resources

【目的】深入了解杨梅种质资源表型性状的多样性特征,为杨梅种质资源的研究和利用提供理论依据和参考。【方法】以95份杨梅地方种质资源为试材,对其果实、果核、叶片和花序等44个表型性状(20个描述型性状和24个数量型性状)观测记录,并进行相关性、聚类和主成分等分析。【结果】20个描述型性状的Shannon-Wiener指数(H)和Simpson指数(D)变化范围分别为0.5125~1.5153和0.2719~0.7660,其中果实颜色、果核核表颜色和果核茸毛颜色等表现出较高的多样性。24个数量型性状的变异系数均值为19.03%,其中果实色泽指标b^(*)值变异系数最大(63.99%)。数量型性状之间的相关性分析结果表明,72对相关系数达极显著水平,23对相关系数达显著水平。主成分分析结果表明,前8个主成分累计贡献率达81.827%,主要反映果实大小、果实色泽、果实糖酸含量等相关因子。根据聚类分析可将95份杨梅种质分为5个类群。【结论】杨梅种质资源表型性状存在丰富的多样性。其中果实单果质量、外观色泽指标、糖酸含量等可作为杨梅品质综合评定的重要指标。95份杨梅种质资源可分为5个类群,其中类群Ⅱ可用于选育大果型优质品种,类群Ⅳ可用于选育优质白梅类品种。

【Objective】Chinese bayberry(Myrica rubra Sieb.et Zucc.)is a subtropical evergreen fruit tree of the Myrica genus in Myricaceae family,bearing delicious,berry-like fruits.The fruit ripens in June and early July in the main production areas of China(i.e.,Zhejiang and Jiangsu provinces),and its colors and appealing flavor are very attractive to the domestic and foreign consumers.The genus Myrica Linn.contains more than 50 species,of which six are found in China,including M.rubra,M.esculenta,M.nana,M.adenophora,M.integrifolia and M.arboresceus,respectively.According to relevant survey statistics,there are more than 300 Chinese bayberry cultivars in China.Diversity analysis of the phenotypic characters is a basic method for the evaluation of germplasm resources.However,there have been few reports on the identification of phenotypic traits of Chinese bayberry.In this study,the phenotypic traits diversity of 95 Chinese bayberry germplasm resources were analyzed in order to provide theoretical foundation for breeding and further utilization of the different bayberry resources.【Methods】In current study,95 accessions of the Chinese bayberry germplasm resources were uesd as test materials,among them,93 belongs to M.rubra,one to M.esculenta and one to M.nana×M.rubra hybrid.A total of 44 phenotypic traits(i.e.,20 descriptive indexes and 24 quantitative indexes)were investigated.The descriptive indexes including the fruit,stone,leaf and inflorescence traits were recorded by description and observation method.The quantitative indexes including the fruit,stone,leaf and inflorescence traits were analyzed by correlation analysis,cluster analysis and principal component analysis.The correlation analysis and principal component analysis were analyzed using SPSS26.0 software,while the cluster analysis was performed using MEGA X software.【Results】The genetic variation in phenotypic traits of 95 accessions of the Chinese bayberry germplasms was abundant.The ShannonWiener index H and Simpson index D of the 20 descriptive traits ranged from 0.5125 to 1.5153 and 0.2719 to 0.7660,respectively.The higher diversity indexes were observed in the fruit color(H:1.4477,D:0.7288),stone fur color(H:1.2240,D:0.6622),and stone color(H:1.5153,D:0.7660),indicating relatively rich genetic diversity in these traits.The mean value of variation coefficient of the 24 quantitative traits was 19.03%,and the highest variation coefficient was observed in the fruit color index b^(*)value(63.99%).The correlation analysis between quantitative traits showed that 72 pairs of correlation coefficients were extremely significant(p<0.01),and 23 pairs of correlation coefficients were significant(p<0.05).The principal component analysis indicated that the cumulative contribution rate of the 8 main principal components was 81.827%,which mainly reflected factors of the fruit size,fruit color,fruit sugar content and acid content.The germplasms were divided into five main groups by the cluster analysis at the Euclidean distance of 20.The GroupⅠcontained only 1 germplasm,namely Maoyangmei,which had the smallest single fruit weight,the smallest fruit vertical diameter,the lowest soluble solids content,the smallest solid-acid ratio and the thinnest leaf thickness among 95 germplasms,suggesting it could be used as a special germplasm resource.The GroupⅡincluded 4 germplasms,which mainly charactered by the large fruit shape and fruit weight.The GroupⅢcontained 3 germplasms.The GroupⅣhad 8 germplasms,which was mainly characterized by the white bayberry germplasms.The GroupⅤincluded 79 germplasms.【Conclusion】The 95 accessions of the Chinese bayberry germplasm resources were rich in genetic variation and high in diversity of phenotypic traits.The single fruit weight,fruit appearance color index,sugar content and acid content could be used as most important indicators for comprehensive evaluation of Chinese bayberry quality.The 95 accessions of the Chinese bayberry germplasm resources could be divided into 5 groups,among them,the groupⅡcould be used for breeding larger fruit and higher quality variety,and the groupⅣcould be used for breeding white bayberry variety.