| Xanthoceras sorbifolium Bunge is one of the bio-energy tree species that.distributes in north China,and its fruit and seed have very high value for comprehensive use,such as extraction of edible and medicinal ingredients,biodiesel,saponin,and activated carbon production.However,the biological characteristics such as low ratio of female flower to male flower and self-incompatibility lead to low natural fruit setting rate.In order to provide base for the scientific allocation of pollination trees and elite clones promotion,five excellent clones of Xanthoceras sorbifolium,No.10,No.14,No.15,No.16,and No.119,were used as materials to study the florescence phenology,stigma receptivity and pollen vigor.And after controlled pollination,the fruit setting rate,seed yield,fruit and seed qualities of each pollination combination were studied.The research results are as follows:1.The flowering stages of 5 clones of Xanthoceras sorbifolium were from April 27th to May 14th.The female flowering stage lasted for 14 to 16 days,and the full flowering stage lasted for 6 to 7 days.The male flowering stage lasted for 15 to 17 days,and the full flowering stage lasted for 7 to 9 days.For the 5 clones the male and female full flowering period matched for 5 to 7 days.2.The stigma receptivity of female flower was higher on the day of flowering and one day after flowering.The pollen viability was higher on the day that flower buds initially opened and the flowering day.Consequently,pollination was carried out when pollen vigor and stigma receptivity were highest.3.Analysis of fruit and seed phenotypic characters and intrinsic quality of pollination combinations showed that clones No.10,No.14,No.15,and No.16,were greatly influenced by their male parents in fruit transverse diameter,fruit longitudinal diameter,single fruit weight,seed transverse diameter,seed longitudinal diameter and seed kernel starch content.There was pollen xenia.Among all cross-pollination combinations(female parentxmale parent),the seed yield and seed kernel oil content of 14×15 were higher,and suitable for biodiesel production.The nerve acid contents of 10×15 and 10×16 were higher(4.50%and 4.18%,respectively),and the unsaturated fatty acid contents of the two combinations were also higher(92.19%and 92.05%,respectively),therefore,they were suitable for high-grade edible oil production.The pollination combinations of 10×15,14×10,15×10,and 16×14 were effective in improvement of fatty acid content,yield factors and economic factors of clone No.10,No.14,No.15 and No.16,respectively.4.The final fruit setting rate of natural pollination of 5 clones was low,ranging from 0 to 7.38%.In practice,pollination trees need to be considered.The combination of male parent and female parent with strong affinity significantly increased the yield of each clone.Clone No.10 as female parent,10CK yield was the lowest(24.92 g),and the other combinations were between 101.25 g and 198.02 g.When clone No.14 was female parent,the yield of other combinations were 11.36 times to 20.44 times of that of 14CK.Clone No.15 as female parent,the yield of other combinations ranged from 81.17 g to 90.33 g,which were significantly higher than the 15CK(47.95 g).Clone No.16 as female parent,the yield of other combinations were significantly higher than which of 16CK(27.31g),and the 16×15 yield was the highest(110.82g),which was 4.05 times of the 16CK.Basing on fertilization rate,final fruit setting rate,seed yield,and fruit and seed qualities of the cross-pollination combinations of each clone,it was concluded that the best pollination combination of clone No.10,No.14,No.15,and No.16,were 10×16,14×15,15×10,and 16×15,respectively.And the 4 clones were not suitable for pollination of No.119.Therefore,in the process of elite germplasm resources promotion,pollination tree plays an important role in determination of fruit setting and fruit and seed characters. |
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