Analysis and Evaluation of Fruit Quality and Volatile Composition of F1 Hybrids between ‘Yuluxiang’ and ‘Shinseiki’ Pear

In order to explore the genetic variation between hybrid fruits and their parents and conduct comprehensive evaluation of hybrid fruits, seven promising F1 hybrids (7-93, 8-44, 8-176, 9-188, 9-193, 10-101 and 10-173) between ‘Yuluxiang’ and ‘Shinseiki’ pears, the female parent ‘Yuluxiang’ and the popular cultivar ‘Akizuki’ were evaluated for quality indicators such as single fruit mass, fruit shape index, hardness, soluble solid content, soluble sugar content, titratable acid content, sugar/acid ratio, vitamin C content, and aroma composition. Meanwhile, the differences in aroma among different cultivars were evaluated using orthogonal partial least squares-discriminant analysis (OPLS-DA). The results showed that there was a significant difference in fruit quality among the seven F1 hybrids, with 8-44 having a fruit shape index equal to 1 and the highest soluble solids and sugar content. Altogether, 83 volatile components were detected from the nine cultivars, of which 10-173 and 8-44 had the highest total amount of volatile components, and 10-173 and 10-101 contained the highest number of volatile compounds. The major aroma components in pears were alcohols, esters, and aldehydes. The OPLS-DA results showed that the aroma components of 10-101 and 10-173 were significantly different from those of the other strains. Fruit quality traits of 10-101 had a significantly positive correlation with ethyl acetate and hexyl acetate; fruit quality traits of 10-173 had a significantly positive correlation with ethyl octanoate and α-farnesene and trans-2-hexenal, and their contents were significantly higher than those in the other strains, making the flavor more prominent. According to variable importance in the projection (VIP) results, we predicted 42 aroma markers that differed among varieties, and through odor activity value (OAV) analysis, we identified key volatile compounds that contributed to the characteristic odor of each strain. Through correlation analysis, we identified the association between pear quality traits and characteristic aromas. Principal component analysis (PCA) showed that the comprehensive scores of 8-44, 10-173 and 10-101 had the highest ranking, indicating that they had better fruit quality than the other strains. In summary, 8-44, 10-101, and 10-173 can be regarded as potential pear strains. This study can provide a reference for the breeding and promotion of new pear varieties.