龙眼种质资源果实性状多样性分析

Analysis on Fruit Character Diversity of Longan(Dimocarps longan Lour)Germplasm Resources

【目的】分析99份龙眼种质资源的果实表型性状指标数据,探讨各资源间的遗传多样性,以期为龙眼种质资源的品质改良、利用及新品种的选育提供理论依据。【方法】通过Q型聚类、R型聚类和主成分分析等方法开展果实数量性状分类研究。【结果】24个描述性状指标中共统计出82个变异表型,果实颜色和果肉质地观察到6个变异表型,果顶形状观察到2个变异表型,平均变异表型为3.42个。各个变异表型出现频率不同,易离核,化渣,无香气,种顶面观椭圆形和不易裂果5个变异表型出现频率均超60%。21个数量性状指标的遗传变异系数介于0.04~0.93,与果穗性状相关指标的遗传变异系数大于果实品质相关指标,可溶性固形物(TSS)含量与总糖、蔗糖、Vc、酸、还原糖含量等指标达到极显著正相关,单果质量与TSS、还原糖、Vc、酸含量等指标达到极显著负相关,与可食率呈极显著正相关;99份龙眼种质资源被分为4个类群,各类种群间果实性状指标差异较为明显。主成分分析结果表明,前15个主成分的累计贡献率为85.956%,可以基本表达45个性状所代表的遗传信息。第一主成分的贡献率为12.071%,主要反映果实大小、外观性状和果穗特征;第二主成分的贡献率为9.465%,主要反映果实内在品质和种子性状。【结论】龙眼果实表型性状指标数据变异明显,出现频率也不相同,表现出明显的遗传多样性。

【Objective】In order to provide a theoretical basis for quality improvement and utilization of longan germplasm resources and the breeding of new varieties, the data of fruit phenotypic characters of 99 longan germplasm resources were analyzed and the genetic diversity among varieties was discussed.【Method】Classification of fruit quantitative characters of 99 longan varieties were investigated by Q-cluster analysis, R-cluster analysis and principal component analysis.【Result】82 variation phenotypes were counted in 24 descriptive characters, six variation phenotypes were observed in fruit color and pulp texture, two variation phenotypes were observed in fruit top shape, and the number of average variation phenotypes was up to 3.42. The frequency of each variation phenotype was different. The average frequency of 5 variation phenotypes of freestone, slag melting, absence oft aril flavour, ellipse in seed top shape and non-cracking fruits was more than 60%. Among 21 quantitative characters, the variation coefficient ranged from 0.04 to 0.93. The genetic variation coefficients of related spike characters were larger than those of the quality characters. Correlation analysis showed that the content of soluble solids was extremely significant positive correlated with that of total sugar, sucrose, Vc, acid and reducing sugar. Single fruit weight was extremely significant negative correlated with the soluble solids content, Vc content, reducing sugar content and acid content, and extremely significant positive correlated with edible rate. The result of Q-cluster analysis showed that 99 longan germplasm resources were divided into 4 groups based on fruit phenotype characters, and there were obvious differences in fruit character indexes among various groups. The results of principal component analysis showed that the cumulative contribution rate of the first 15 principal components was 85.956%, which could basically express the genetic information represented by 45 characters. The contribution rate of the first principal component was 12.071%, which mainly reflected the fruit size, appearance quality and ear characteristics;the contribution rate of the second principal component was 9.465%, which mainly reflected the internal quality of fruit and seed characters.【Conclusion】Significant variations were found in the fruit phenotypic character indexes of 99 longan germplasm resources, and the frequency of each phenotypic variation was also different, showing obvious genetic diversity.