Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants, Ministry of Education, Haikou, 570228, China.
College of Forestry, Hainan University, Haikou, 570228, China.
Sci Rep. 2022 Jan 10;12(1):371. doi: 10.1038/s41598-021-03775-x.
Calamansi or Philippine lime (Citrofortunella macrocarpa) is an important crop for local economic in Hainan Island. There is no study about Calamansi germplasm evaluation and cultivar development. In this study, Calamansi data were collected from 151 of Calamansi seedling trees, and 37 phenotypic traits were analyzed to investigate their genetic diversities. The cluster analysis and principal component analysis were conducted aiming to provide a theoretical basis for the Calamansi genetic improvement. The results of the diversity analysis revealed: (1) the diversity indexes for qualitative traits were ranged from 0.46-1.39, and the traits with the highest genetic diversity level were fruit shaped and pulp colored (H' > 1.20); and the diversity indexes for quantitative traits ranged from 0.67-2.10, with the exception of a lower in fruit juice rate (1.08) and lower in number of petals (0.67). (2) The clustering analysis of phenotypic traits have arranged the samples into 4 categories: the first group characterized by fewer flesh Segment number per fruit (SNF) and more Oil cell number (OCN); the second group had 7 samples, all characterized with larger Crown breadth (CB), higher Yield per tree (YPT), the lager leaf, the higher Ascorbic acid (AA), and less Seed number per fruit (SNPF); the third group had 25 samples characterized by smaller Tree foot diameter (TFD),smaller Fruit shape index (FSI) and higher Total soluble solids (TSS) contain; the fourth group had 87 samples, they were characterized by shorter Petiole length (PEL), larger fruit, higher Juice ratio (JR), multiple Stamen number (SN) and longer Pistil length (PIL). (3) The principal component analysis showed the values of the first 9 major components characteristic vectors were all greater than 3, the cumulative contribution rate reach 72.20%, including the traits of single fruit weight, fruit diameter, tree height, tree canopy width etc. Finally, based on the comprehensive main component value of all samples, the Calamansi individuals with higher testing scores were selected for further observation. This study concludes that Calamansi seedling populations in the Hainan Island holds great genetic diversity in varies traits, and can be useful for the Calamansi variety improvements.
海南岛上的菲律宾青柠（Citrofortunella macrocarpa）是一种重要的经济作物。目前，关于菲律宾青柠种质资源评价和品种选育的研究还很少。本研究收集了 151 株菲律宾青柠实生苗的数据，并对 37 个表型性状进行了分析，以研究其遗传多样性。通过聚类分析和主成分分析，为菲律宾青柠的遗传改良提供了理论依据。多样性分析结果表明：（1）定性性状的多样性指数范围为 0.46-1.39，其中果实形状和果肉颜色的遗传多样性水平最高（H' > 1.20）；定量性状的多样性指数范围为 0.67-2.10，除果汁率较低（1.08）和花瓣数较低（0.67）外。（2）表型性状聚类分析将样品分为 4 类：第一组果实果肉段数（SNF）较少，油细胞数（OCN）较多；第二类有 7 个样本，均具有较大的冠宽（CB）、较高的单株产量（YPT）、较大的叶片、较高的抗坏血酸（AA）和较少的果实种子数（SNPF）；第三组有 25 个样本，具有较小的树脚直径（TFD）、较小的果实形状指数（FSI）和较高的总可溶性固形物（TSS）含量；第四组有 87 个样本，具有较短的叶柄长度（PEL）、较大的果实、较高的出汁率（JR）、较多的雄蕊数（SN）和较长的雌蕊长度（PIL）。（3）主成分分析表明，前 9 个主要特征向量的特征值均大于 3，累计贡献率达到 72.20%，包括单果重、果径、树高、树冠宽等性状。最后，根据所有样本的综合主成分值，选择测试得分较高的菲律宾青柠个体进行进一步观察。本研究表明，海南岛菲律宾青柠实生苗群体在各种性状上均具有较大的遗传多样性，可用于菲律宾青柠品种改良。
