Variation Of The Fruit And Seed Phenotypic Traits And The Selection Of The Comprehensive Evaluation Of Different Mating Combinations In Xanthoceras Sorbifolium Bunge

Xanthoceras sorbifolium Bunge is the most potential woody oil tree species in northern China,but it has yield problems of flower abortion and self-incompatible.The fruit and seed phenotypic traits of X.sorbifolium were studied in this thesis to discuss genetic variation in different regions and the different mating combinations in the same area were comprehensively evaluated and selected.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.(1)Four population of X sorbifolium in different regions were studied,The results showed that:The phenotypic diversity of the fruit and seed phenotypic traits of the X.sorbifolium was high,and there was extensive variability existed among populations and groups;The amplitude of variation of CV(coefficient of variation)of fruit and seed phenotypic traits under the inflorescence scale and fruit scale in different regions were both comparatively large;the change of the X.sorbifolium caused by environmental changes was relatively large.The range of variation in the four regions was Huangyangjing>Shuangjing>Yangzhangzi>Dadongliu;Some fruit and seed phenotypic traits had close correlation;The correlation between the fruit and seed phenotypic traits and geographical and climatic factors was not significant at all,and that the elevation affected the number of seeds and the weight of seeds.The annual precipitation affected the total weight and the ratio of seed weight.(2)Six types of X.sorbifolium(Six types refer to type A,B,G1,G3,H5 and N7 based on rootcut graft of X.sorbifolium)were used to conduct the open/hand-pollination experiment in a X.sorbifolium seeds orchard in semi-arid region of Aohan Banner,Inner Mongolia.The experiment including 36 mating combinations of self-crossing,intercrossing,and open pollination.The results showed that there was Significant differences and high heterosis in X.sorbifolium,and the heterosis of interspecific hybrids was greater than intraspecific hybridization,and strong heterosis could be obtained by selecting proper control-pollination.All types of X.sorbifolium were ranked as G1>A>B>N7>H5>G3 according to the comprehensive performance of the female parent,and were ranked as H5>N7>G3>B>G1>A>ck according to the comprehensive performance as the male parent.(3)The comprehensive evaluation of 36 mating combinations was selected by Canoco-PCA-TOPSIS method.The results showed that:The results showed that there was high heterosis in X.sorbifolium,and strong genetic gain could be obtained by selecting excellent mating combinations.The combination B×H5,G1×G3,and BxN7 were the best mating combinations for evaluating the overall fruit and seed phenotypic traits.The newly discovered self-cross(cross-pollination)advantage,H5 is the best monophyletic mating combination;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.