Germplasm resources are an important basis for genetic breeding and analysis of complex traits,and research on genetic diversity is conducive to the exploration and creation of new types of germplasm.In this study,the...Germplasm resources are an important basis for genetic breeding and analysis of complex traits,and research on genetic diversity is conducive to the exploration and creation of new types of germplasm.In this study,the distribution frequency,coefficient of variation,Shannon-Wiener index,and variance and cluster analyses were used to analyze the diversity and trait differences of 39 fruit phenotypic traits from 570 pear accessions,which included 456 pear accessions from 11 species and 114 interspecific hybrid cultivars that had been stored in the National Germplasm Repository of Apple and Pear(Xingcheng,China).The comprehensive evaluation indices were screened by correlation,principal component and regression analyses.A total of 132 variant types were detected in 28 categorical traits of pear germplasm fruit,which indicate a rich diversity.The diversity indices in decreasing order were:fruit shape(1.949),attitude of calyx(1.908),flesh texture type(1.700),persistency of calyx(1.681),russet location(1.658),relief of area around eye basin(1.644),flavor(1.610)and ground color(1.592).The coefficient of variation of titratable acidity in the 11 numerical traits of pear germplasm fruit was as high as 128.43%,which could more effectively reflect the differences between pear accessions.The phenotypic differentiation coefficient V_(st)(66.4%)among the five cultivated pear species,including Pyrus bretschneideri(White Pear),P.pyrifolia(Sand Pear),P.ussuriensis(Ussurian Pear),P.sinkiangensis(Xinjiang Pear),and P.communis(European Pear),was higher than the within population phenotypic differentiation coefficient V_(st)(33.6%).The variation among populations was the main source of variation in pear fruit traits.A hierarchical cluster analysis divided the 389 accessions of six cultivated pear species,including P.pashia(Himalayan Pear),into six categories.There were certain characteristics within the populations,and the differences between populations were not completely clustered by region.For example,Sand Pear cultivars from Japan and the Korean Peninsula clustered together with those from China.Most of the White Pear cultivars clustered with the Sand Pear,and a few clustered with the Ussurian Pear cultivars.The Ussurian Pear and European Pear cultivars clustered separately.The Xinjiang Pear and Himalayan Pear did not cluster together,and neither did the cultivars.Seventeen traits,three describing fruit weight and edible rate(fruit diameter,fruit length and fruit core size),five describing outer quality and morphological characteristics(over color,amount of russeting,dot obviousness,fruit shape,and stalk length),and nine describing inner quality(flesh color,juiciness of flesh,aroma,flavor,flesh texture,flesh texture type,soluble solid contents,titratable acidity,and eating quality)were selected from the 39 traits by principal component and stepwise regression analyses.These 17 traits could reflect 99.3%of the total variation and can be used as a comprehensive evaluation index for pear germplasm resources.展开更多
利用传统的k匿名技术在社会网络中进行隐私保护时会存在聚类准则单一、图中数据信息利用不足等问题.针对该问题,提出了一种利用Kullback-Leibler(KL)散度衡量节点1-邻居图相似性的匿名技术(anonymization techniques for measuring the ...利用传统的k匿名技术在社会网络中进行隐私保护时会存在聚类准则单一、图中数据信息利用不足等问题.针对该问题,提出了一种利用Kullback-Leibler(KL)散度衡量节点1-邻居图相似性的匿名技术(anonymization techniques for measuring the similarity of node 1-neighbor graph based on Kullback-Leibler divergence,SNKL).根据节点1-邻居图分布的相似性对原始图节点集进行划分,按照划分好的类进行图修改,使修改后的图满足k匿名,完成图的匿名发布.实验结果表明,SNKL方法与HIGA方法相比在聚类系数上的改变量平均降低了17.3%,同时生成的匿名图与原始图重要性节点重合度保持在95%以上.所提方法在有效保证隐私的基础上,可以显著的降低对原始图结构信息的改变.展开更多
基金supported by the China Agriculture Research System of MOF and MARA(CARS-29-01)the Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-ASTIP2016-RIP-01)。
文摘Germplasm resources are an important basis for genetic breeding and analysis of complex traits,and research on genetic diversity is conducive to the exploration and creation of new types of germplasm.In this study,the distribution frequency,coefficient of variation,Shannon-Wiener index,and variance and cluster analyses were used to analyze the diversity and trait differences of 39 fruit phenotypic traits from 570 pear accessions,which included 456 pear accessions from 11 species and 114 interspecific hybrid cultivars that had been stored in the National Germplasm Repository of Apple and Pear(Xingcheng,China).The comprehensive evaluation indices were screened by correlation,principal component and regression analyses.A total of 132 variant types were detected in 28 categorical traits of pear germplasm fruit,which indicate a rich diversity.The diversity indices in decreasing order were:fruit shape(1.949),attitude of calyx(1.908),flesh texture type(1.700),persistency of calyx(1.681),russet location(1.658),relief of area around eye basin(1.644),flavor(1.610)and ground color(1.592).The coefficient of variation of titratable acidity in the 11 numerical traits of pear germplasm fruit was as high as 128.43%,which could more effectively reflect the differences between pear accessions.The phenotypic differentiation coefficient V_(st)(66.4%)among the five cultivated pear species,including Pyrus bretschneideri(White Pear),P.pyrifolia(Sand Pear),P.ussuriensis(Ussurian Pear),P.sinkiangensis(Xinjiang Pear),and P.communis(European Pear),was higher than the within population phenotypic differentiation coefficient V_(st)(33.6%).The variation among populations was the main source of variation in pear fruit traits.A hierarchical cluster analysis divided the 389 accessions of six cultivated pear species,including P.pashia(Himalayan Pear),into six categories.There were certain characteristics within the populations,and the differences between populations were not completely clustered by region.For example,Sand Pear cultivars from Japan and the Korean Peninsula clustered together with those from China.Most of the White Pear cultivars clustered with the Sand Pear,and a few clustered with the Ussurian Pear cultivars.The Ussurian Pear and European Pear cultivars clustered separately.The Xinjiang Pear and Himalayan Pear did not cluster together,and neither did the cultivars.Seventeen traits,three describing fruit weight and edible rate(fruit diameter,fruit length and fruit core size),five describing outer quality and morphological characteristics(over color,amount of russeting,dot obviousness,fruit shape,and stalk length),and nine describing inner quality(flesh color,juiciness of flesh,aroma,flavor,flesh texture,flesh texture type,soluble solid contents,titratable acidity,and eating quality)were selected from the 39 traits by principal component and stepwise regression analyses.These 17 traits could reflect 99.3%of the total variation and can be used as a comprehensive evaluation index for pear germplasm resources.
文摘利用传统的k匿名技术在社会网络中进行隐私保护时会存在聚类准则单一、图中数据信息利用不足等问题.针对该问题,提出了一种利用Kullback-Leibler(KL)散度衡量节点1-邻居图相似性的匿名技术(anonymization techniques for measuring the similarity of node 1-neighbor graph based on Kullback-Leibler divergence,SNKL).根据节点1-邻居图分布的相似性对原始图节点集进行划分,按照划分好的类进行图修改,使修改后的图满足k匿名,完成图的匿名发布.实验结果表明,SNKL方法与HIGA方法相比在聚类系数上的改变量平均降低了17.3%,同时生成的匿名图与原始图重要性节点重合度保持在95%以上.所提方法在有效保证隐私的基础上,可以显著的降低对原始图结构信息的改变.
