Selection of superior individual Pistacia chinensis based on 24 phenotypic traits

Objective This study was conducted to address the current situation of lack of improved varieties and low yield in China, and to provide application materials for the selection and breeding of improved varieties of Pistacia chinensis.

Method Twenty-four indicators, including yield traits and quality traits, were measured on 88 germplasm resources from seven provinces (cities and autonomous regions) in China and statistical methods such as correlation analysis, cluster analysis and principal component analysis were used to analyze the variation among the indicators and to quantitatively evaluate each economic trait.

Result (1) The fruit traits of P. chinensis showed rich diversity, with great variation in yield and oil-producing capacity, relatively large variation in fruit volume, surface area and 100-fruit mass, and relatively small variation in appearance traits. The variation in all indicators was less in healthy fruit than that in unhealthy fruit. (2) Yield per tree was highly significantly positively correlated with bearing branch rate, number of the bearing branch, number of the fruit cluster per branch, number of the fruit per fruit cluster and number of the fruit per tree, respectively. Oil content was highly significantly positively correlated with healthy fruit rate, number of the fruit cluster per branch, yield per tree, yield of the unit crown area and 100-fruit mass, respectively. (3) Cluster analysis classified the germplasm into four groups: low-yielding ancient tree group, large-fruited group, medium-fruited group and small-fruited group. (4) Using principal component analysis, 10 superior germplasms were selected, five from the large-fruited group and five from the medium-fruited group. The top three overall scores were all from large-fruited taxa, with an average gain of 56.49%.

Conclusion The wide variation of the fruit traits of P. chinensis provides a large scope for the selection and breeding of improved varieties of P. chinensis. The large-fruited group is prone to produce superior individuals with very high overall scores, while the medium-fruited group is prone to stably produce superior individuals with high overall scores. The Shaanxi and Shandong regions have the environmental conditions suitable for the development of P. chinensis industry, and have more potential for the development of P. chinensis oil species.