ObjectiveXanthoceras sorbifolium is the most potential woody oil tree species in northern China, but it has yield problems of flower abortion and self-incompatible. This paper dataly analyzes the variation and comprehensive evaluation of the fruit and seed phenotypic traits of different mating combinations in Xanthoceras sorbifolium. The aim is to improve the yield.

MethodSix types of X. sorbifolium (six types refer to type A, B, G1, G3, H5 and N7 based on rootcut graft of X. sorbifolium in 2014) were used to conduct the open/hand-pollination experiment in a X. sorbifolium seed orchard in the semi-arid region of Aohan Banner, Inner Mongolia of northern China. The experiment included 36 mating combinations of self-crossing, intercrossing and open pollination. The evaluation of the best mating combination by Canoco-PCA-TOPSIS was based on 10 fruit traits (such as fruit quality and average grain quality).

ResultAccording to Canoco principal component analysis (Canoco-PCA), first 2 principal components contributed more than 90% of the factors. The main component score matrix for each mating combinations was used to establish comprehensive evaluation, while TOPSIS was used for sorting 36 mating combinations of fruit and seed phenotypic traits. The results were divided into 3 groups according to whether the results were suitable as excellent mating combinations, the most suitable excellent mating combinations, suitable general mating combinations, and unsuitable poor mating combinations, and the accuracy of discriminant analysis was over 96.3%.

ConclusionThe results showed that there was high heterosis in X. sorbifolium (family heritability >30%), and strong genetic gain could be obtained by selecting excellent mating combinations. The mating combination with the highest total fruit weight was G1×G3. The mating combination with the largest single seed weight was H5×B. The combination B×H5, G1×G3, and B×N7 were the best mating combinations for evaluating the overall fruit and seed phenotypic traits. For the newly discovered self-cross (cross-pollination) advantage, H5 was the best monophyletic mating combination. For the newly discovered intercrossing advantage, the optimal two-line mating combination was G1 and G3; and the optimal three-line mating combination was N7, B and H5. The established method of comprehensive evaluation and selection could effectively select excellent mating combinations, which could provide scientific basis and mating arrangement model in increasing the yield of X. sorbifolium in the future.