Abstract:

To establish a set of methods for rapid screening of excellent apple varieties, 11 apple varieties were selected to measure 12 indices of the fruit quality in Ili River Valley. The standardization method was used to carry out the transformation and principal component analysis of indicators. The result showed that there were different degrees of correlation between the quality indicators of apple fruit. There were significant correlations between single fruit weight and fruit vertical diameter, fruit weight and fruit transverse diameter, fruit vertical diameter and fruit transverse diameter, vitamin C and total sugar, fruit vertical diameter and hardness. Based on the results of principal component analysis, five factors were extracted from the converted data matrix, and their cumulative contribution reached 92.811%. The first principal component was the fruit appearance factor with a variance contribution rate of 44.207%; the second principal component was the fruit flavor factor with a variance contribution rate of 21.379%; the third principal component was the nutritional factor with a variance contribution rate of 12.841%; the fourth principal component was the acidity factor with a variance contribution rate of 8.906%; the fifth principal component was the hardness factor with a variance contribution rate of 5.478%. A comprehensive evaluation model for fruit quality of different apple varieties was established based on the variance contribution rates of five principal components as weights. The comprehensive quality ranking results show that ‘Qincui’, ‘Ruiyang’, ‘Yimei’, ‘Ruixue’, and ‘Jinxiuhong’ have outstanding fruit quality. It is recommended that these apple varieties can be promoted and applied in the Ili River Valley.

Key words: apple, fruit quality, economic traits, principal component analysis, selection of excellent varieties