Abstract:
Xinjiang Autonomous Region has been the main pear producing area in China, due to the unique climate conditions. The types and tastes of local pear cultivars have brought rich germplasm resources to maintain the genetic diversity of pear under the climatic changes and the evolving demand of a market. A Pyrus sinkiangensis Yü belonging to Pomaceae of Rosaceae is the major component of oriental pears. However, a simplex pear variety has become an increasingly prominent issue in recent years. In particular, Korla fragrant pear with relatively concentrated market time cannot meet the ever-increasing high demand for diversified pear variety. Therefore, it is necessary to breed local pear varieties with different maturity, diversified taste, and individualization for better sustainable development of characteristic forest and fruit industry in Xinjiang. In this study, a quality evaluation model was established for 8 types of local pear cultivars using factor analysis. Eight types of test materials included ‘Piqan red pear’, ‘Piqanjujula’, ‘Piqanpock marked yellow pear’, ‘late-maturing tax pear’, ‘Piqan early-maturing jujula’, ‘Nogay pear’, ‘Yaglik pear’, and ‘Kuqajujula’. 14 internal and external indexes of fruit quality were selected to determine the comprehensive quality score. The results showed that there were great differences in the variation coefficient of 14 fruit quality indexes in 8 types of local pear cultivars, where the maximum variation coefficient was the color difference value a* (red-green difference) of 225.40%. There were the medium variation coefficients of single fruit weight, fruit longitudinal diameter, fruit core weight, color difference value L*, fruit hardness, total acid content, and sugar-acid ratio, ranging from 20.0% to 45.0%. Furthermore, relatively small variation coefficients (<20.0%) were found in the rest of the fruit quality indexes. There were also different levels of correlation among the fruit quality indexes. Additionally, a factor analysis was utilized to extract four common factors with eigenvalues greater than 1, where the cumulative variance contribution rate was 88.90%. Specifically, the contribution rate of the first common factor was 31.15%, which was mainly determined by the fruit longitudinal diameter, single fruit weight, fruit core weight, fruit transverse diameter, and fruit shape index, indicating the fruit size, core size, and fruit shape. The contribution rate of the second common factor was 23.31%, which was determined by the sugar-acid ratio, fruit firmness, sugar content, and total acid content, indicating the taste quality and the strength of transportation. The third common factor accounted for 18.29%, which was determined by the color difference value L*, a*, and b*, representing the color difference level of the fruit surface. The contribution rate of the fourth common factor was 16.15%, which was determined by the edible rate and the length of the fruit stalk, reflecting the size of the edible part and the wind resistance of the fruit. An excellent level order of 8 local pear cultivars was achieved in the quality evaluation model: ‘Nogay pear’, ‘Yaglik pear’, ‘Kuqajujula’, ‘Piqanpock marked yellow pear’, ‘Piqanjujula’, ‘Piqan red pear’, ‘Piqan early-maturing jujula’, and ‘late-maturing tax pear’. The results provide reference for rational application and scientific popularization of local pear cultivars in Xinjiang.