A Model for Selecting Kiwifruit (Actinidia eriantha) Germplasm Resources with Excellent Fruit Quality

Abstract

The evaluation of quality traits is an important procedure for kiwifruit breeding and comprehensive utilization. The present study aimed to establish a comprehensive system to assess Actinidia eriantha germplasms by analyzing 22 quality traits on kiwifruit samples collected from a wild population of 236 plants grown in the Jiangxi Province, China. Variability, correlation, principal components, and cluster analyses were carried out using the data collected from fruit quality evaluations. The coefficients of variation (CV) of fruit quality traits ranged from 11.66 to 66.16% (average coefficient = 35.09%), indicating a high level of variation among the 236 plants. In addition, different degrees of correlations were found between the traits, with similar traits demonstrating strong correlations. Principal component analysis (PCA) generated eight comprehensive and independent principal components, accounting for 77.93% of the original fruit quality information. Furthermore, an extensive evaluation from PCA ranked the plants based on cluster analysis and grouped them into seven categories. A stepwise regression analysis generated a prediction model, demonstrating a good fit (0.945) with the principal components of the comprehensive evaluation score. Overall, this study identifies nine quality traits, representing fruit appearance, sweetness, acidity, flavor, and nutritional attributes, as important traits for a comprehensive evaluation of A. eriantha fruits.

Keywords: Actinidia eriantha; comprehensive evaluation; fruit quality; germplasm resources; key traits.

Figure 1

Box plots and scatter plots showing the normal distribution of the fruit quality traits. (A) Longitudinal diameter, (B) Transverse diameter, (C) Fruit shape index, (D) Fruit weight, (E) Dry matter, (F) Soluble solids, (G) Total soluble suger, (H) TItratable acid, (I) Solid-acid ratio, (J) Suger-acid ratio, (K) L-ascorbic acid, (L) Total phenol, (M) Total flavonoids, (N) Fructose, (O) Glucose, (P) Surcose, (Q) Quinic acid, (R) Malic acid, (S) Citric acid, (T) Oxalic acid, (V) Lactic acid, (U) Fumaric acid.

Figure 2

Correlation clustering heat map of the 22 fruit quality traits. Positive correlations are shown in red and negative correlations are shown in blue. Here, * and ** represent statistical significance at p < 0.05 and p < 0.01, respectively.

Figure 3

Cluster analysis of 236 wild A. eriantha germplasm plants. Category I are shown in red, category II are shown in blue, category III are shown in yellow, category IV are shown in purple, category V are shown in green, category VI are shown in orange, and category VII are shown in blank.