Abstract:

Objective In recent years, fruit quality is the main factor of the apple market competitiveness, and the diversity of fruit quality traits in different apple germplasm resources is studied and analyzed to cultivate new varieties and create new germplasm. Methods Twenty-three apple germplasms were evaluated for differences in fruit quality indicators including individual fruit weight, firmness without skin, soluble solid content, vitamin C, soluble sugar content, titratable acidity，TSS/TA. Meanwhile, these quality indicators were analyzed by correlation analysis and principal component analysis (PCA). Results The results showed that the seven quality indicators revealed a significant difference among 23 different apple germplasm. There is a significantly positive correlation between titratable acidity and vitamin C. There is a significantly positive correlation between titratable acidity and individual fruit weight. There is a significantly negative correlation between TSS/TA and vitamin C. There is a significantly negative correlation between TSS/TA and titratable acidity as well. Three major components with a characteristic value larger than 1 during PCA were extracted and the cumulative variance contribution rate was 73.21%. The first principal component represented TSS/TA, vitamin C, titratable acidity; the second principal component represented individual fruit weight; the third principal component represented firmness without skin, soluble solid content, soluble sugar content. Conclusion There is significant difference in seven fruits quality traits of twenty-three apple germplasm resources. Different germplasm has different typical traits. In these 23 apple germplasm resources, the fruit size of 'Yan Guang' is the highest. 'Huang Taiping' has the highest firmness without skin and soluble solid content. ‘Suan Wang' has the highest content of acid and vitamin C. ‘Zhang Jiakouduanzhi' has the highest soluble sugar content. The TSS/TA of 'Guo Shuai' is the highest.

Key words: apple germplasm resources, fruit quality traits, diversity