Research Progress on Genetic Diversity and Its Ecological Conservation of Endangered Dongxiang Wild Rice (Oryza rufipogon Griff.)

It is of great importance for the analysis on genetic evolution mechanism, and rice breeding utilization by estimation and protection of genetic diversity of pre- sent DXWR （Oryza rufipogon Griff.）. This study has summarized genetic diversity and protection achievements of DXWR from many aspects like varied conservations, years, generations, other species of wild rice and cultivated rice. In this study, a u- nified and scientific evaluation system of genetic diversity is encouraged to be built and suggestions on research prospect and ecological conservation of DXWR genetic diversity have been proposed.

Sampling strategy for wild soybean(Glycine soja)populations based on their genetic diversity and fine-scale spatial genetic structure

A total of 892 individuals sampled from a wild soybean population in a natural reserve near the Yellow River estuary located in Kenli of Shandong Province(China)were investigated.Seventeen SSR(simple sequence repeat)primer pairs from cultivated soybeans were used to estimate the genetic diversity of the population and its variation pattern versus changes of the sample size(sub-samples),in addition to investigating the fine-scale spatial genetic structure within the population.The results showed relatively high genetic diversity of the population with the mean value of allele number(A)being 2.88,expected heterozygosity(He)0.431,Shannon diversity index(I)0.699,and percentage of poly-morphic loci(P)100%.Sub-samples of different sizes(ten groups)were randomly drawn from the population and their genetic diversity was calculated by computer simulation.The regression model of the four diversity indexes with the change of sample sizes was computed.As a result,27-52 individuals can reach 95%of total genetic variability of the population.Spatial autocorrelation analysis revealed that the genetic patch size of this wild soybean population is about 18 m.The study provided a scientific basis for the sampling strategy of wild soybean populations.

Assessing the conservation impact of Chinese indigenous chicken populations between ex-situ and in-situ using genome-wide SNPs

Conservation programs require rigorous evaluation to ensure the preservation of genetic diversity and viability of conservation populations. In this study, we conducted a comparative analysis of two indigenous Chinese chicken breeds, Gushi and Xichuan black-bone, using whole-genome SNPs to understand their genetic diversity, track changes over time and population structure. The breeds were divided into five conservation populations(GS1, 2010, ex-situ;GS2, 2019, ex-situ;GS3, 2019, in-situ;XB1, 2010, in-situ;and XB2, 2019, in-situ) based on conservation methods and generations. The genetic diversity indices of three conservation populations of Gushi chicken showed consistent trends, with the GS3 population under in-situ strategy having the highest diversity and GS2 under ex-situ strategy having the lowest. The degree of inbreeding of GS2 was higher than that of GS1 and GS3. Conserved populations of Xichuan black-bone chicken showed no obvious changes in genetic diversity between XB1 and XB2. In terms of population structure, the GS3 population were stratified relative to GS1 and GS2. According to the conservation priority, GS3 had the highest contribution to the total gene and allelic diversity in GS breed, whereas the contribution of XB1 and XB2 were similar. We also observed that the genetic diversity of GS2 was lower than GS3, which were from the same generation but under different conservation programs(in-situ and ex-situ). While XB1 and XB2 had similar levels of genetic diversity. Overall, our findings suggested that the conservation programs performed in ex-situ could slow down the occurrence of inbreeding events, but could not entirely prevent the loss of genetic diversity when the conserved population size was small, while in-situ conservation populations with large population size could maintain a relative high level of genetic diversity.

Establishment of a Core Collection for the Chinese annual wild soybean (Glycine Soja)

With more than 6000 accessions collected from across China, the Chinese National Crop Gene Bank (CNCGB) holds the largest collection of annual wild soybean (Glycine Soja) germplasm in the world. To facilitate the management and utilization of these germplasm collections, it is important to establish a Core Collection. This study compares five sampling strategies, namely random, constant, proportional, logarithmic and genetic diversity-based, to establish a Core Collection for the annual wild soybean germplasm. Among the strategies evaluated, the genetic di- versity-based was found to be the simplest and most efficient. Using hierarchical classification and cluster analysis, in the genetic diversity diversity-based strategy, 652 accessions, accounting for 10.65% of the total 6172 accessions, were se- lected out to represent the total accessions. The established Core Collection has the following features: (i) the 21 de- scriptors observed in the entire collection were compared by the Core Collection, all 18 quality characters of entire collec- tion were preserved by core collection, and coincidence rate of average was 98.4%; (ii) the variant of 13 descriptors of the two collections was very similar, with the coincidence index being 0.96; (iii) the coincidence rate of genetic diversity be- tween the two collections was 81.38% DNA alleles; (iv) the geographic distribution pattern of core collection was the same as the entire collection; (v) molecular marker analysis by 20 SSR primer pairs on 299 accessions showed that the Core Collection covered 83.64% of the entire collection. It thus is concluded that the established Core Collection is rep- resentative and will be a valuable entry point for better evaluation and more efficient utilization of the genetic re- sources available in the annual wild soybean germplasm bank.

Genetic diversity,geographic differentiation and evolutionary relationship among ecotypes of Glycine max and G. soja in China

The knowledge of origin and evolution of cultivated soybeans is one of the basic issues in both biology and agronomy of the crop. In order to investigate the nuclear and cytoplasmic genetic diversity, geographic differentiation and genetic relationship among geographic ecotypes of cultivated (Glycine max) and wild (G. soja) soybeans, the allelic profiles at 60 nuclear simple-sequence repeat (nuSSR) loci and 11 chloroplastic SSR (cpSSR) loci evenly distributed on whole genome of 393 landraces and 196 wild accessions from nation-wide growing areas in China were analyzed. (i) The genetic diversity of the wild soybean was obviously larger than that of the cultivated soybean, with their nuSSR and cpSSR alleles as 1067 vs. 980 and 57 vs 44, respectively. Of the 980 nuclear alleles detected in the cultivated soybean, 377 new ones (38.5%) emerged, while of the 44 chloroplastic alleles in the cultivated soybean, seven new ones (15.9%) emerged after domestication. (ii) Among the cultivated geographic ecotypes, those from southern China, including South-Central China, Southwest China and South China possessed relatively great genetic diversity than those from northern China, while among the wild geographic ecotypes, the Middle and Lower Changjiang Valleys wild ecotype showed the highest genetic diversity. (iii) The analysis of molecular variance, association analysis between geographic grouping and molecular marker clustering and analysis of specific-present alleles of ecotypes demonstrated that the geographic differentiation of both cultivated and wild soybeans associated with their genetic differentiation, or in other words, had their relevant genetic bases. (iv) The cluster analysis of all accessions clearly showed that the wild accessions from Middle and Lower Changjiang Valleys and South-Central & Southwest China had relatively small genetic distances with all cultivated accessions. The UPGMA dendrogram among geographic ecotypes further showed that the genetic distances between all cultivated ecotypes and the Middle and Lower Changjiang Valleys wild ecotype were smaller than those with other wild ones, including their local wild counterparts. Therefore, it is inferred that the wild ancestors in southern China, especially those from Middle and Lower Changjiang Valleys might be the common ancestor of all the cultivated soybeans.

辽宁新宾县原位保护区野生大豆（Glycine soja Sieb．＆Zucc．）遗传多样性分析

首次从辽宁新宾县野生大豆原位保护区10个自然居群采集了150株野生大豆叶片样本，利用居群个体DNA等量混合建池，用53对徽卫星（SSR）引物进行遗传多样性分析，目的是建立野生大豆原位保护群体多样性快速评价方法，为野生大豆原位保护点的选择提供理论依据。在参试材料中共检测到123个等位变异，平均每个位点2．3个。经相似系数矩阵分析，发现用20～25对引物进行分析与用53对引物的分析结果可达极显著相关。因此，选择了25对SSR引物对150个个体进行深入分析，结果表明，居群期望杂合度（He）为0．317，群体间分化系数（Fst）为0．667，说明居群内分化较小，大部分遗传变异存在于居群间。居群间基因流强度很小（Nm=0．119），遗传多样性分布不均匀，异位保护取样时，应从不同居群中采集样本。随机抽样分析表明，40个左右样本可保留95％的遗传变异。

中国野生大豆遗传多样性中心

本文采用群体遗传学方法 ,研究分析了 6172份中国野生大豆资源的数量、遗传多样性指数( Shannon指数 )、 12个性状的综合变异系数及其地理分布。结果表明 :142～ 4 7°N× 12 2～ 12 7°E的东北中南部野生大豆资源分布极广、遗传多样性丰富、综合变异系数高 ;2 34～ 35°N× 113～ 115°E、 38～ 39°N× 113～ 115°E和 34～ 35°N× 10 7～ 10 9°E的黄河中下游和秦岭山区野生大豆次之 ;3 2 6～ 2 7°N× 119～ 12 1°E的东南沿海地区野生大豆遗传多样性、综合变异系数均很高 ,但分布较少。根据遗传多样性、综合变异系数及资源的地理分布 ,提出了中国野生大豆遗传多样性中心及多样性扩散 ,据此推测了中国野生大豆的起源模式 ,为栽培大豆的起源提供了一个重要依据。

不同尺度下野大豆种群的遗传分化

为了阐明不同尺度范围内野大豆种群的遗传分化情况 ,应用随机扩增多态性 DNA( RAPD)方法 ,分别对我国 5个纬度 8个不同地点的野大豆 ( Glycine soja)种群及浙江金华地区 5个野大豆种群 ,进行了分子生态学研究。根据 RAPD数据计算相似系数及遗传距离并进行聚类分析 ,发现无论是不同纬度野大豆种群还是金华地区野大豆小种群均存在较高的遗传变异 ,且不同纬度野大豆种群间的遗传变异与地理纬度有一定正相关。在对金华地区野大豆种群遗传多样性的研究中 ,利用 Shannon指数估算了 5个野大豆种群的遗传多样性 ,发现大部分的遗传变异存在于野大豆种群间 ( 78.5 %) ,只有少部分的遗传变异存在于种群内。本文就此探讨了不同尺度下野大豆种群的遗传多样性与环境因子的关系 ,并对其成因及维持机制进行了讨论。

中国不同纬度野生大豆和栽培大豆SSR分析

采用SSR分子标记技术对我国不同纬度的野生大豆 (G soja )和栽培大豆 (G max )各 2 2份进行了多样性分析 ,通过对所合成的 4 0对引物的筛选 ,12对引物扩增结果表现出良好的多态性。引物BARC -sat39在野生大豆和栽培大豆之间有特异谱带。表明这个SSR标记是与栽培大豆和野生大豆有关的一个等位基因位点。通过对实验结果量化后数据分析 :野生大豆和栽培大豆的平均遗传距离分别为 0 176和 0 15 0 ,表明野生大豆的多态性比栽培大豆较为丰富 ;在遗传距离0 30 0处 ,野生大豆和栽培大豆被明显分为二类 ,与以往大豆属Soja亚属的形态学分类结果相一致 ,为野生大豆和栽培大豆分为二个种提供了分子水平上的证据。

中国野生大豆(G.soja)籽粒性状的遗传多样性及其地理分布

本文分析了中国野生大豆资源5279份百粒重、种皮色、泥膜、脐色等籽粒性状的多样性及其地理分布。发现:（1）81.1％材料的百粒重≤2.5g。（2）百粒重的大小与种皮色、泥膜、脐色有密切联系。（3）籽粒性状的变异中心主要分布在黄河流域和东北地区的东南部。根据中国野生大豆籽粒性状的综合表现,讨论了:（1）根据百粒重,野生大豆分型如下:百粒重≤2.5g为“野生型”,2.51-5g为“半野生Ⅰ型”,> 5g为“半野生Ⅱ型”。（2）根据野生大豆籽粒性状的变异中心,提出大豆起源于我国北方。除了黄河流域以外,东北的东南部很可能是另一起源地。

云南元江普通野生稻(Oryza rufipogon Griff)遗传多样性分析及保护策略研究

用SSR方法对云南元江普通野生稻 3个自然居群进行 30个位点的遗传多样性分析。结果表明 ,元江普通野生稻具有较高的遗传变异水平 (Ap =2 6 ,Hs=0 77) ,且群体遗传分化系数较大 ,GST为 4 1 0 8% ,即在遗传变异总量中 4 1 0 8%存在于居群间。本文还通过对云南元江普通野生稻遗传多样性特点的分析 。

半野生大豆种质资源SSR位点遗传多样性分析

利用 1 2对 SSR引物对 67份半野生大豆种质进行了遗传多样性的检测分析。结果表明 ,1 2个位点共检测到 1 84个等位基因变异 ,平均每个位点等位基因数目为 1 5.41个。平均多态性信息量、平均遗传多样性指数、平均遗传距离分别为 0 .849、0 .70 6、0 .1 1 8。根据 SSR分析结果 ,按欧式距离将 67份半野生大豆种质聚类并划分为

中国一年生野生大豆群体的遗传多样性研究

选用来自全国各地的一年生野生大豆２００ 余份材料，从形态性状、等位酶标记和细胞器ＤＮＡＲＦＬＰ标记的遗传丰富度和遗传离散度两方面分析了中国野生大豆群体的遗传多样性．结果表明：中国野生大豆天然群体存在着遗传分化，各地理生态群体间的遗传多样性水平不同，南方群体最高，黄淮海群体次之，东北群体最低．南方为一年生野生大豆的遗传多样性中心，也可能是起源中心．

江西野生大豆遗传多样性分析

利用48对SSR引物分析了192份采集于江西49个县(区)的野生大豆遗传多样性。结果表明,共扩增出等位基因343个,平均每对引物扩增出7.2个等位基因,平均基因遗传多样性指数0.7369,平均多态性信息含量(PIC)0.7060,表明江西野生大豆具有较为丰富的遗传多样性。不同纬度和不同海拔的野生大豆其遗传多样性不同,高纬度及低海拔地区野生大豆遗传多样性要高。192份野生大豆可聚类成3大类,聚类结果与地理来源较为一致。

中国不同纬度野生大豆和栽培大豆AFLP分析

采用AFLP分子标记技术 ,对我国不同纬度的 2 0份野生大豆 (G .soja)和栽培大豆 (G .max)进行了多样性分析 ,结果表明 :( 1)我国野生大豆的遗传多样性较栽培大豆更为丰富 ;( 2 )根据AFLP分析结果 ,将野生大豆和栽培大豆完全划分为 2类 ,并发现野生大豆和栽培大豆的种特异谱带 ,说明野生大豆和栽培大豆作为 2个种是有遗传基础的 ;( 3)野生大豆和栽培大豆不同纬度品种间纬度相近的首先聚在一起 ,表明不同进化类型的大豆其遗传距离与纬度可能存在一定的相关性。本研究的结果为大豆分类、进化、起源等研究提供一定的证据 。

中俄大豆种质遗传多样性分析

种质资源的扩增、改良和创新是解决大豆遗传基础狭窄的主要途径。利用SSR分子标记技术对来自俄罗斯和黑龙江省的82份野生大豆和东北四省区的39份栽培大豆材料进行遗传多样性分析，为种质资源利用和创新提供分子依据。在所合成的45对SSR引物中，12对引物扩增结果表现出良好的多态性，多态性位点共检测到50个等位基因，每个位点2～7个，平均4．17个，平均多态性信息量为0．595。聚类分析结果表明，在遗传相似系数0．734处，野生大豆和栽培大豆被明显的分开，与以往大豆属Soja亚属的形态学分类结果相一致，为野生大豆和栽培大豆分为两个种提供了分子水平上的依据。野生大豆和栽培大豆的平均遗传距离分别为0．2595和0．1895，表明野生大豆的遗传多样性比栽培大豆丰富。因此，可以利用俄罗斯和东北地区的野生大豆特有等位变异来扩大东北栽培大豆遗传多样性，进而拓宽东北大豆遗传基础。

广西火桐自然种群和迁地保护种群的遗传多样性比较

采用ISSR标记方法,对广西火桐Erythropsis kwangsiensis 10个自然种群和1个迁地保护种群的遗传多样性和遗传结构进行了分析和比较。结果表明:用10个引物从广西火桐总DNA中共扩增出60条带,其中多态性条带51条。自然种群中以维新种群的遗传多样性最高,而三叠岭瀑布种群最低。自然种群的总遗传变异Ht为0.281 5,种群内遗传变异HS为0.076 4,种群间遗传变异为0.205 1,基因流为0.183 2。迁地保护种群的HEt和HES均为0.118 8。自然种群间存在一定程度的遗传分化(Gst=0.731 9),种群间变异占主导地位。合并后的自然种群的多态性条带百分率(RPPB)、Nei’s多样性指数(H)和Shannon信息指数(I)均高于迁地保护种群,分别为85.00%和31.67%、0.284 1和0.118 8、0.428 5和0.175 7。研究结果表明:广西火桐迁地保护种群的遗传多样性较低,未能涵盖整个种群。建议从多个自然种群中收集种子,尽可能多的采集样本,分区育苗种植,以增加遗传多样性水平。

大豆种质资源RAPD标记遗传多样性研究

为深入研究并充分利用野生大豆资源,本文利用RAPD分子标记对40份大豆材料加以分析,旨在从DNA分子水平上探索野生大豆、地方品种和育成品种之间的遗传多样性状况。结果表明:50个RAPD引物筛选出具有多态性且扩增条带清晰的引物38个,共检测出407条带,其中多态谱带309条,多态性程度为75.92%。每个引物可扩增出2～14条多态性带,平均产生多态性谱带8.1条;平均多样性指数为2.3377,变幅范围为0.5865～4.2133。遗传相似系数变幅范围为0.44～0.92,平均为0.75。野生大豆的多态比例(94.35%)、多样性指数(2.2336)分别高于育成品种(87.47%、1.7331)和地方品种(83.54%、1.6198)。遗传相似系数为野生大豆(0.6498)<地方品种(0.7015)<育成品种(0.7177),育成品种与地方品种间为0.6599,育成品种与野生大豆间为0.6487,地方品种与野生大豆间为0.6045。UPGMA聚类分析结果表明,40份大豆材料聚为6类,育成品种和地方品种各自聚为一类,野生大豆聚为4类。野生大豆特异等位基因数远远高于育成品种和地方品种二者的相加之和。本研究从分子水平上揭示了野生大豆与栽培大豆区别明显,宜作为一个独立的种,同时野生大豆变异幅度大,遗传基础广,是大豆育种实践中的优良基因资源。

河北东部沿海地区野生大豆SSR多样性分析

以采集于冀东沿海地区的370及黑龙江省的2份野生大豆为材料,利用27对SSR引物进行遗传多样性分析。27个SSR位点扩增出209个多态性带,平均每个位点等位基因数目为7.74个,SSR位点的遗传多样性指数分布范围,Simpson指数为0.3998～0.8358,Shannon-weaver指数为0.7567～1.9879,冀东沿海地区野生大豆材料表现出丰富的遗传多样性。聚类分析结果中冀东靠近海岸线地区的材料与内陆材料之间存在着明显的遗传差异;同一居群的材料遗传距离很近,有些不同居群的材料由于生境相似遗传距离也较近;然而有些同一居群内的材料表现出了明显的遗传分化。

新考察收集野生大豆与已保存野生大豆的遗传多样性比较

本研究以 6 5份东北地区新收集野生大豆资源以及与其来源相同的已经编目保存的资源为实验材料 ,利用 6 0对SSR引物进行遗传分析。分析结果表明新收集材料在 2 2个位点的遗传多样性指数都高于以前收集的资源 ,有 6 2个等位变异是新收集材料所特有。新收集材料与其它资源间的平均遗传相似系数为 0 1918。说明新收集的材料使得野生大豆的遗传多样性水平得到提高 ,对野生大豆进行补充考察和收集是有价值的。