Comprehensive evaluation of fruit quality of 88 accessions of Actinidia arguta germplasm resources based on principal component analysis and correlation analysis

[Objective] Correlation analysis and principal component analysis were used to comprehensively evaluate the quality traits of 88 accessions of Actinidia arguta resources preserved in the A. arguta resource nursery of the Institute of Specialty Products, Chinese Academy of Agricultural Sciences, in order to establish a fruit evaluation system and provide theoretical basis for the screening of high-quality A. arguta resources. [Methods] Using 88 accessions of A. arguta fruit resources as test material, the transverse, longitudinal and lateral diameters of the fruits were measured with vernier calipers, the mass of the fruits was measured with a balance, the soluble solid content was measured with a portable digital brix meter, the titratable acid content was measured with a titration method using sodium hydroxide solution, the total sugar content was measured with a sulfuric acid-anthracenone colorimetric method, and the total phenol content was measured with a Folin-phenol method. The titric acid, quinic acid, malic acid, lactic acid and vitamin C content were measured using High Performance Liquid Chromatography. Correlation analysis and principal component analysis were used for comprehensive evaluation. [Results] Differences were found among the 15 quality indexes of the fruits of the different A. arguta germplasm resources, and there were correlations among the indexes. The maximum fruit transverse diameter (33.07 mm) was found in 111002, the maximum fruit longitudinal diameter (44.49 mm) in L060503, and the maximum fruit lateral diameter (30.07 mm) in S090602. The fruit mass ranged from 4.13 to 18.31 g. The maximum fruit mass was found in L060503. The soluble solids content varied in the range of 7.13% to 17.73%, and the highest content was found inL080308, followed by 0600203. The titratable acid content ranged from 2.76 to 15.69 g·L-1, and the highest content was found in W030101. The solid-acid ratio of W010401 fruits reached a maximum of 4.93. The total sugar content varied from 14.27 to 88.02 g·L-1, the highest content was found in T100503. The total phenol content varied from 0.41 to 1.82 mg·g-1, and the highest content was found in W110101. The highest organic acid content was found in 060203, and the highest vitamin C content was found in W110101. The results of correlation analysis showed that the transverse and lateral diameters of the fruits were significantly and positively correlated with the fruit mass and significantly and negatively correlated with the fruit shape index. The solid-acid ratio had a highly significant and negative correlation with the titratable acid content and a highly significant and positive correlation with the total sugar content. The total phenolic content showed highly significant and positive correlation with the citric acid content, quinic acid content, malic acid content, and vitamin C content. The 15 quality indexes of the soft date kiwifruit were simplified and extracted, and the components with eigenvalues greater than 1 were extracted, and a total of five principal components were extracted, with a cumulative contribution rate of 75.384%, and the contribution rate of the 1st principal component amounted for 20.819%, and the titratable acid, vitamin C, and citric acid positively affected the 1st principal component, which mainly reflected the nutritive qualities of the fruits. The contribution of the 2nd principal component was 19.790%, which was mainly represented by the transverse and longitudinal diameters of the fruit and the quality of the single fruit, reflecting the appearance quality of the fruit. The contribution of the 3rd principal component was 15.490%. The main representatives were the soluble solids and total sugar, reflecting the sugar content of the fruit. The contribution of the 4th principal component was 11.062%, which showed a highly significant positive correlation with the fruit shape index, and the contribution of the 5th principal component was 8.222%, which showed a significant and positive correlation with the quinic acid and lactic acid. [Conclusion] The correlation analysis and principal component analysis screened out fruit transverse and longitudinal diameter, single fruit mass, soluble solid content, titrable acid content, total sugar content, total phenol content, organic acid content and vitamin C content as the core indexes for fruit quality evaluation. L060503, 060203, 190403, L110203, 040103 were the top 5 quality resources of A. arguta.