Genetic Diversity Of Castanea Henryi Cultivars Based On Phenotypic Characters And Molecular Markers

Castanea henryi(Skam)Rehd.et Wils is the famous woody grain and ruit-timber tree in southern China.It can select parents in advance more scientifically and reasonably by studying on genetic diversity of C.henryi cultivars.In this study,17 C.henryi cultivars grown in Jian’ou city of Fujian province were analyzed in genetic diversity by studying phenotypic traits variation such as the morphological characters of fruit and leaf,fruit nutrition indexes,growth and yield,combining with the application of SSR and SRAP molecular markers.The results of this study provide a basis for selection of parents in crossbreeding and genetic mapping.The main results are as follows:1.From the variation of 27 phenotypic traits in C.henryi cultivars,it could be concluded that there was a rich variation between different cultivars and a certain correlation between the phenotypic traits.The potential for selection and the joint selection of phenotypic traits was large.The variation coefficient was between 8.91%and 64.29%,with an average of 27.32%.The lowest variation coefficient was the content of starch,and the largest was the yield per plant.The highest correlation coefficient was 0.828,between yield and knot bracteal number.The repeatability of each trait was high with an average of 0.805.Through the comprehensive evaluation of phenotypic traits,the top three were ’Wuzhen’,’Youzhen’and’Chushuhong’.Based on fruit nutrient content and yield,’Chushuhong’,’Wuzhen’ and ’Dajianzui’ showed superior grades.Clustering results showed that 17 cultivars were divided into 4 classes.’Chushuhong’ was in the first class;’Youzhen’ was in the second class;There were 4 cultivars in the third class:’Dabaozhen’,’Tiezhui’,’Dajianzui’ and ’Hongzizhen’;There were 11 cultivars in the fourth class:’Huangzhen’,’Bailuzi’,,’Xiaojianzui’,’Niujiaozi(late mature)’,’Shuangfengzi’,’Niujiaozi(middle mature)’,’Zhongjianzui’,’Youtongzi’,’Wuzhen’,’Wukechangmang’and ’Ouningzi’.2.Ten screened from 256 SRAP primer combinations were used to analyze the genetic diversity of 17 cultivars.It obtained 200 bands,the polymorphic bands was 183,and the percentage of polymorphic bands was 91.5%,which indicated that there was a large genetic difference among these cultivars.The genetic similarity coefficient was between 0.5082 and 0.7978,with an average of 0.6530.The closest genetic relationship was between ’Dajianzui’ and’Zhongjianzui’,and the farthest genetic relationship was between’Dajianzui’ and ’Xiaojianzui’.As the dendrogram by SRAP marker,17 Castanea henryi cultivars were divided into 3 classes.There were 3 cultivars in the first class:’Chushuhong’,’Shuangfengzi’ and’Wukechangmang’;There were 11 cultivars in the second class:’Dabaozhen’,’Niujiaozi(late mature)’,’Wuzhen’,,’Tiezhui’,’Niujiaozi(middle mature)’,’Ouningzi’,’Hongzizhen’,’Huangzhen’,’Youtongzi’,’Bailuzi’ and ’Youzhen’;There were 3 cultivars in the third class:’Dajianzui’,’Zhongjianzui’ and ’Xiaojianzui’.An SRAP fingerprint was built for the 17 cultivars by em2me8.3.Twelve screened from 40 SSR primer combinations were used to analyze the genetic diversity of 17 cultivars.It obtained 180 bands,the polymorphic bands was 163,and the percentage of polymorphic bands was 90.56%,which indicated that there was a large genetic difference among these cultivars.The genetic similarity coefficient was between 0.5092 and 0.8821,with an average of 0.6657.The closest genetic relationship was between ’Wukechangmang’ and’Niujiaozi(late mature)’,and the farthest genetic relationship was between ’Zhongjianzui’ and ’Bailuzi’.As the dendrogram by SSR markers,17 cultivars were divided into 3 classes.’Chushuhong’was in the first class;There were 14 cultivars in the second class:’Shuangfengzi’,’Wuzhen’,’Wukechangmang’,’Niujiaozi(late mature)’,’Youzhen’,’Dabaozhen’,&Huangzhen’,’Tiezhui’,’Youtongzi’,’Xiaojianzui’,’Bailuzi’,’Hongzizhen’,’Ouningzi’ and’Niujiaozi(middle mature)’;’Dajianzui’ and ’Zhongjianzui’ were in the third class.An SSR fingerprint was built for the 17 cultivars by CsCAT33 and CmTCR4.4.The data of both SSR and SRAP were used to analyze the varieties of C.henryi.cultivars.It obtained 380 bands,the polymorphic bands was 346,and the percentage of polymorphic band was 91.05%,which indicated that there was a large genetic difference among these cultivars.The genetic similarity coefficient was between 0.5231 and 0.7601,with an average of 0.6416.The closest genetic relationship was between ’Dabaozhen’ and ’Wuzhen’,and the farthest genetic relationship was between ’Zhongjianzui’ and ’Bailuzi’.17 C.henryi cultivars were divided into 3 classes.There were 3 cultivars in the first class:’Chushuhong’,’Shuangfengzi’ and ’Wukechangmang’;There were 12 cultivars in the second class:’Dabaozhen’,’Niujiaozi(late mature)’,’Wuzhen’,’Tiezhui’,’Huangzhen’,’Niujiaozi(middle mature)’,’Hongzizhen’,’Ouningzi’,’Bailuzi’,’Youzhen’,’Youtongzi’ and ’Xiaojianzui’;’Dajianzui’ and’Zhongjianzui’were in the third class.The clustering results of SRAP are highly similar with the clustering results obtained by the combination of two molecular markers.Combining the results of phenotypic traits with molecular markers,it could be considered as cross breeding parents of high guality:’Chushuhong’ and ’Wuzhen’,’Chushuhong’ and ’Dajianzui’;It could be considered as cross breeding parents:’Chushuhong’ and ’Niujiaozi(late mature)’,’Chushuhong’ and ’Bailuzi’ and ’Wuzhen’ and ’Wukechangmang’.It could be considered as parents for genetic mapping:’Dajianzui’ and’Bailuzi’ and ’Wuzhen’ and ’Zhongjianzui’.