We have compared genetic diversity of 24 Chinese weak-winter, Swedish winter and spring B. napus accessions by inter-simple sequence repeats (ISSRs). By cluster analysis (UPGMA) based on 125 polymorphism bands amplifi...We have compared genetic diversity of 24 Chinese weak-winter, Swedish winter and spring B. napus accessions by inter-simple sequence repeats (ISSRs). By cluster analysis (UPGMA) based on 125 polymorphism bands amplified with 20 primers, the 24 accessions were divided into three groups. Six Swedish winter lines and eight Chinese weak-winter lines were in the group I and the groupⅡwere two Chinese weak-winter lines XiangyoulS and Bao81. The third group contained eight Swedish spring lines. Principal co-ordinates analysis (PCO) showed similar groupings to cluster analysis. Results from cluster analysis and PCO analysis showed very clearly that Chinese weak-winter, Swedish spring and winter accessions were distinguished from each other and Chinese weak-winter accessions in this study were genetically closer to Swedish winter accessions than to Swedish spring accessions. The Chinese weak-winter accessions had larger diversity than Swedish spring or winter accessions did. This study indicated that ISSR is a suitable and effective tool to evaluate genetic diversity among rapeseed germplasm.展开更多
Inter-simple Sequence Repeat （ISSR） analysis was applied to assess the genetic diversity within and among five populations of mink from Liaoning Province. A total of 20 primers were screened, five selected primers p...Inter-simple Sequence Repeat （ISSR） analysis was applied to assess the genetic diversity within and among five populations of mink from Liaoning Province. A total of 20 primers were screened, five selected primers produced 35 discernible bands, with 30 （85.71%） being polymorphic, indicating high genetic diversity at the species level. The highest genetic diversity was observed in the brown mink population, whereas the lowest diversity was found in the standard-pitchy mink population. Based on genetic distance （1972）, a dendrogram was constructed by using UPGMA algorithm, and five populations were divided into two major groups. Group I consisted of only the standard-pitchy mink population, and Group II included other four populations, in Group II, sapphire mink was close to brown mink population. The results of genetic differentiation indicated that the genetic differentiation degree between populations was lower and the genetic variation primarily came from within populations. This paper showed that ISSR technique was a reliable tool that could be used to study genetic diversity in the mink.展开更多
Sugarcane is an important tropical crop, responsible for two thirds of the world sugar production, gaining actually importance as a source of biofuel. Drought tolerance is a very important feature considering the actu...Sugarcane is an important tropical crop, responsible for two thirds of the world sugar production, gaining actually importance as a source of biofuel. Drought tolerance is a very important feature considering the actual climate change scenario throughout the world. This study aimed to determine the genetic diversity between sugarcane varieties with contrasting features under drought. For this purpose, twelve ISSR primers were used to characterize nine sugarcane varieties under cultivation in different countries including selected drought resistant material from Northeast Brazil and two varieties from India as contrasting genotypes. 317 scorable bands were generated, among which 301 comprised polymorphic markers, with an average of 25 polymorphic bands per primer. In the generated dendrogram the accessions were placed in clusters, where cluster A included two varieties from India (Co331 and Co419), and B comprised plants eight Brazilian accessions and a ‘Barbado’ variety. Within this clade, drought tolerant and susceptible varieties were clearly separated. The present evaluation revealed important contrasting parental candidates regarding their drought response, very promising for future mapping approaches aiming the identification of quantitative trait loci (QTLs) associated to drought in sugarcane. The selected primers were used for the first time in sugarcane, representing valuable tools for future evaluations, with emphasis to diversity characterization and genetic mapping.展开更多
Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported....Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported. In the present study, inter sequence simple repeats (ISSR) molecular markers were employed to assess genetic diversity and relationships of 83 accessions of Jute mallow from different parts of Africa and Asia conserved at the World Vegetable Center East and Southern Africa. A total of 89 bands were amplified by 8 ISSR primers. Number of polymorphic bands per primer ranged from 2 to 6 with an average of 2.75 bands per primer. Polymorphic information content (PIC) values ranged from 0.390 to 0.760 with average of 0.53. Average Nei’s gene diversity (h) and Shannon’s information index (I) were 0.335 and 0.494 respectively. The highest pairwise genetic distance was 0.431 observed in a population from East Africa accessions. PC1 and PC2 axis explained 21.69% and 11.66% of the total variation respectively. UPGMA cluster analysis grouped the accessions into six main clusters at genetic similarity coefficient of 0.53 as standard value for classification. These results have important implications for jute mallow breeding and conservation.展开更多
文摘We have compared genetic diversity of 24 Chinese weak-winter, Swedish winter and spring B. napus accessions by inter-simple sequence repeats (ISSRs). By cluster analysis (UPGMA) based on 125 polymorphism bands amplified with 20 primers, the 24 accessions were divided into three groups. Six Swedish winter lines and eight Chinese weak-winter lines were in the group I and the groupⅡwere two Chinese weak-winter lines XiangyoulS and Bao81. The third group contained eight Swedish spring lines. Principal co-ordinates analysis (PCO) showed similar groupings to cluster analysis. Results from cluster analysis and PCO analysis showed very clearly that Chinese weak-winter, Swedish spring and winter accessions were distinguished from each other and Chinese weak-winter accessions in this study were genetically closer to Swedish winter accessions than to Swedish spring accessions. The Chinese weak-winter accessions had larger diversity than Swedish spring or winter accessions did. This study indicated that ISSR is a suitable and effective tool to evaluate genetic diversity among rapeseed germplasm.
文摘Inter-simple Sequence Repeat （ISSR） analysis was applied to assess the genetic diversity within and among five populations of mink from Liaoning Province. A total of 20 primers were screened, five selected primers produced 35 discernible bands, with 30 （85.71%） being polymorphic, indicating high genetic diversity at the species level. The highest genetic diversity was observed in the brown mink population, whereas the lowest diversity was found in the standard-pitchy mink population. Based on genetic distance （1972）, a dendrogram was constructed by using UPGMA algorithm, and five populations were divided into two major groups. Group I consisted of only the standard-pitchy mink population, and Group II included other four populations, in Group II, sapphire mink was close to brown mink population. The results of genetic differentiation indicated that the genetic differentiation degree between populations was lower and the genetic variation primarily came from within populations. This paper showed that ISSR technique was a reliable tool that could be used to study genetic diversity in the mink.
文摘Sugarcane is an important tropical crop, responsible for two thirds of the world sugar production, gaining actually importance as a source of biofuel. Drought tolerance is a very important feature considering the actual climate change scenario throughout the world. This study aimed to determine the genetic diversity between sugarcane varieties with contrasting features under drought. For this purpose, twelve ISSR primers were used to characterize nine sugarcane varieties under cultivation in different countries including selected drought resistant material from Northeast Brazil and two varieties from India as contrasting genotypes. 317 scorable bands were generated, among which 301 comprised polymorphic markers, with an average of 25 polymorphic bands per primer. In the generated dendrogram the accessions were placed in clusters, where cluster A included two varieties from India (Co331 and Co419), and B comprised plants eight Brazilian accessions and a ‘Barbado’ variety. Within this clade, drought tolerant and susceptible varieties were clearly separated. The present evaluation revealed important contrasting parental candidates regarding their drought response, very promising for future mapping approaches aiming the identification of quantitative trait loci (QTLs) associated to drought in sugarcane. The selected primers were used for the first time in sugarcane, representing valuable tools for future evaluations, with emphasis to diversity characterization and genetic mapping.
文摘Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported. In the present study, inter sequence simple repeats (ISSR) molecular markers were employed to assess genetic diversity and relationships of 83 accessions of Jute mallow from different parts of Africa and Asia conserved at the World Vegetable Center East and Southern Africa. A total of 89 bands were amplified by 8 ISSR primers. Number of polymorphic bands per primer ranged from 2 to 6 with an average of 2.75 bands per primer. Polymorphic information content (PIC) values ranged from 0.390 to 0.760 with average of 0.53. Average Nei’s gene diversity (h) and Shannon’s information index (I) were 0.335 and 0.494 respectively. The highest pairwise genetic distance was 0.431 observed in a population from East Africa accessions. PC1 and PC2 axis explained 21.69% and 11.66% of the total variation respectively. UPGMA cluster analysis grouped the accessions into six main clusters at genetic similarity coefficient of 0.53 as standard value for classification. These results have important implications for jute mallow breeding and conservation.
