Study On Flowering Characteristics And Pollination Configuration Of Four Varieties Of The Introduced Chestnut In Longan County Of Guangxi Zhuang Autonomous Region

Castanea mollissima is an important economic forest species over Chinese area,especially in Guangxi area.C.mollissima is dioecious on the same plant and the synchronization and the desynchronization of the male and the female happen at the flowering stage,which often results in low yields and seriously causes the enthusiasm of fruit farmers to plant and manage C.mollissima.In this thesis,Shuangji,Chushuhong,Jiujiazhong and Fengkai 2#which were the main C.mollissima varieties introduced from Longan of Guangxi were taken as the research objects,and this thesis carried out the research on flowering habits,pollen characteristics,and pollination configuration effects.Also,it discussed and evaluated the possibility of the four varieties as pollinating trees each other,to provide a basis for the high-yield cultivation of C.mollissima in Guangxi.The main research results were as follows.1.There were differences in phenological periods among the four imported C.mollissima varieties.The sequence of bud initiation,leaf expansion,male emergence,female emergence,flowering and deflowering of each variety was Fengkai 2#,Shuangji,Jiujiazhong and Chushuhong.2.The male and the female flowering types of the four introduced chestnut varieties were female-first type and hermaphrodite type which contained the synchronization and the desynchronization of the male and the female happened as the different species and the synchronization and the desynchronization of the male and the female happened as the same species.Jiujiazhong and Chushuhong were female-first types and the desynchronization of the male and the female happens as the same species during the open period.Fengkai 2#and Shuangji were hermaphrodite types and the synchronization of the male and the female happens as the same species during the open period.The opening period of the male flowers of Shuangji synchronizing with the female flowers of the other three varieties sustained 3 days to 4 days.The male flowering period of Fengkai2#synchronizing with the female flowering period of the other three varieties sustained for 3 days to 8 days.The flowering period of male flowers of Chushuhong and Jiujiazhong was later than the other two varieties,and the synchronization of their males and the females did not happen.3.The ratio of mixed flowering branches of C.mollissima from high to low was Shuangji（77.8%）>Chushuhong（72.2%）>Jiujiazhong（69.4%）>Fengkai2#（47.2%）.The average number of female inflorescences of Shuangji,Chushuhong,Jiujiazhong and Fengkai 2#were respectively 1.7 per branch,1.3per branch,1.2 per branch and 0.8 per branch.Chushuhong,Shuangji and Jiujiazhong emerged as the biological basis of high yield.4.The pollen grains of each variety were normal,and the pollen germination rate was Fengkai 2#（15.49%）>Jiujiazhong（11.77%）>Shuangji（7.02%）>Chushuhong（3.77%）,The pollen germination rate of all varieties was relatively low,but the amount of the pollen of per male inflorescence was more than 2 million,which made up for the lack of germination rate.In the solid medium 0.05 g/L H₃BO₃,0.01 g/L Zn SO₄and 0.05 g/L Ca Cl₂,the pollen germination rate of the four varieties was higher.5.The fruit maturity,bud size,bud setting rate,empty bud rate,seed setting rate and seed emergence rate of each pollination combination had obvious pollen xenia effects.Pollenating with the pollen of Shuangji,the author found that four varieties of C.mollissima had less empty bud rate,high seed setting rate and seed emergence rate,and found there was no obvious difference the from natural pollination with the good compatibility.When Fengkai 2#was taken as a pollination tree,C.mollissima had a high empty bud rate,low seed setting rate and seed emergence rate,which was quite different from the natural pollination and with the poor compatibility.6.The xenia effect of pollen affected fruit quality,and the different varieties of chestnut were affected to different degrees by the male parent.Nut soluble sugar,soluble protein,starch content,vitamin C and crude protein had a certain pollen xenia effect,but water content and fat content influenced rarely by the xenia effect.Different pollination treatments had different effects on the content of N,P,K,Ca,Mg,Cu,Mn,Zn mineral elements in nuts,and also had a phenomenon of pollen intuition.7.The principal component analysis of pollination effect and the comprehensive analysis of membership function reflected that the total score and membership degree of the principal components were higher for Shuangji pollination combination,which had good fruit setting and fruit quality,but Fengkai 2#pollination combination had poor fruit setting and fruit quality.Based on the above results,Shuangji and Fengkai 2#did not need to be equipped with pollinating trees,and Chushuhong and Jiujiazhong needed to be equipped with pollinating trees.Shuangji was the best pollination tree for the other three varieties.