| Cucubita pepo L.is an annual herbaceous plant belonging to the Cucurbitaceae Cucurbita,has rich nutrition,important medicinal value and economic value.It has strong adaptability and a large cultivated area,more and more people like it.The study of genetic diversity analysis of C.pepo will contribute to germplasm collection,classification,identification,effective utilization and conservation.Morphological markers reflected the differences among the germplasm,and the molecular markers reflected differences among the DNA.ISSR morphological marker had the advantages of simple operation,high resolution,high repeatability,high polymorphism and high security,and had been widely used in variety identification and diversity analysis.In the study,the genetic diversity of 44 C.pepo varieties were analyzed by using morphological and ISSR markers.The main results are as follows:1.13 morphological characteristic were facilitated to assess diversity among 30 parent materials and 14 varieties.The results showed that there were rich diversities in the 13 morphological indexes.Among 30 parent materials,the coefficient of variation of the plant width was maximum,the diameter of the old melon was minimum.The maximum and minimum of the Shannon diversity index were leaf area and growth habit,respectively.Among 14 varieties,the coefficient of variation of the growth habit was maximum,the fruit shape index was minimum.The maximum and minimum of the Shannon diversity index were petiole length and diameter of the old melon,respectively.2.The results of morphological markers showed that 30 parents materials were divided into 3 groups according to coefficient 0.20.The first category included 30 and 33,they were male parent,the shape of their melon were long long rod;the second category consisted of the male parent of long rod;the other one was the 18 kinds of female parent materials,which were made up of the round,short cylinder,cylinder and long cylinder.The 14 varieties were divided into 3 groups according to coefficient 0.23.No.34,as a whole;the second category included 6 bush materials and the third types included 7 semi-bush materials.Fruit shape and the form of vine were important for C.pepo.3.18 polymorphic primers were selected from 50 ISSR primers,which generated 203 DNA bands.Among them,153 were polymorphic bands,polymorphic rate was 74.9%,and 11.3 bands and 8.4 polymorphic bands were amplified by each primer on average.The average values of Na、Ne、Hand I were 2、1.6117、0.3493、0.5182,respectively.4.The results of ISSR markers showed that the female parent and male parent materials were clustered into different groups,and the 30 parent materials were divided into 2 groups at the similarity coefficient of 0.55.The first class was two male materials,the shape of their melon were long long rod;at the coefficient 0.67,28 materials were divided into 4 subcategories,4 female materials of cylindrical,4 female materials of long cylinder,11 male materials of long long rod and 9 female materials of round to short tube.The 14 varieties were divided into 4 groups at the similarity coefficient of 0.62.The first class included 6 bush materials,the second class included 3 semi-bush materials,the third class included 4 semi-bush materials,the round material was alone.5.The results of morphological markers and ISSR markers were the same.From the results of parent materials,the male parent materials of long long rod were clustered together firstly,other parent materials were female group and male group,the difference was the female parent materials was divided into 3 sub-groups by ISSR markers;From the results of varieties,34 was alone,the other sub-groups was bush varieties and semi-bush varieties,but the semi-bush varieties were clustered into two groups by ISSR markers.Morphological markers and ISSR markers were compared,the correlation coefficient was 0.4228 of varieties,the correlation coefficient was 0.2012 of parent materials,that is,in the present study,the classification of the test materials by the two markers had a low consistency.6.The results of ISSR marker showed that the similarity coefficient between parent materials was 0.55-1,14 and 5、12 and 15 and 9、3 and 18、23 and 26 were the same materials respectively.We can saw the background of materials for breeding was narrow,in the future we should collect the resources widely. |
