广西邕宁普通野生稻(Oryza rufipogon Griff.)种群遗传多样性及核心种质构建研究

[目的]研究广西邕宁普通野生稻种群的遗传多样性和核心种质构建,为普通野生稻种群保护提供依据。[方法]从水稻12条染色体上均匀选取24对SSR标记对243份样本进行遗传多样性分析。[结果]结果表明,24对引物均表现出多态性,多态位点比率为100%;24个多态位点共检测出103个等位变异,平均等位基因数A为4.291 7,平均有效等位基因数E是2.511 2,平均期望杂合度He为0.573 2,平均多态信息含量PIC为0.572 0。根据聚类结果分析,从243份材料中筛选出31份核心种质,包含了24个SSR位点检测到的所有的遗传变异,其平均期望杂合度He是0.595 8,平均多态信息含量PIC是0.586 3,基本上可以代表广西邕宁普通野生稻种群的遗传多样性。[结论]广西邕宁普通野生稻资源具有丰富的遗传多样性。

普通野生稻Oryza rufipogon Griff.生态分化的初探

为探讨普通野生稻 Oryza rufipogon Griff.的生态分化式样 ,对中国的 31个天然居群及其生境进行了考察。通过对其生活史特性、生长习性、抽穗光周期、百粒重和繁育系统的初步观察后得到如下结果 :1)在中国没有发现一年生的天然居群 ;2 )随着纬度的升高 ,普通野生稻的繁育系统有从无性生殖向有性生殖偏移的趋势 ;3)适应日照长度变化的结果使其始穗期有随着纬度的升高而提早的趋势 ;4 )茎的生长习性的多型性与周围栽培稻的基因流有关 ,在小生境中水分条件的差异亦可导致生长习性从匍匐到直立的渐变。但是 。

中国普通野生稻(Oryza rufipogon Griff.)原生境保护与未保护居群的遗传多样性比较

为了明确我国已建立的普通野生稻原生境保护居群的遗传多样性状况及其代表性,利用24对SSR引物对15个原生境保护居群的427份普通野生稻材料和在我国野生稻分布区内按照纬度划分后随机挑选的15个未保护居群的357份普通野生稻材料进行遗传多样性分析。结果表明,保护居群24个位点的平均有效等位基因数(Ae)为5.98,平均香农指数(I)为1.90,均大于未保护居群在24个位点的平均Ae(5.85)和I(1.86)值,但保护居群在24个位点的平均预期杂合度(He)为0.79,略小于未保护居群He值(0.80)。显著性检验结果显示,保护居群和随机挑选的未保护居群在24个位点上及居群水平上的Ae、I和He值差异不显著,表明保护居群可以代表我国普通野生稻的遗传多样性状况。保护居群的特有等位变异数(Sa)为40,远大于未保护居群的20,说明保护居群保护了更多的特殊基因,具有较高的保护价值。根据前人的研究结果,对应普通野生稻保护居群的地理信息,发现15个保护居群涵盖了我国普通野生稻分布区内所有已知的典型地理类型,表明我国普通野生稻原生境保护居群具有典型性。由此可以看出,我国已建立的15个普通野生稻原生境保护点的选择是科学合理的。根据对我国普通野生稻遗传结构的分析,建议下一步开展的普通野生稻原生境保护点建设应以广西南部及广东为主。

广西普通野生稻(Oryza rufipogon Griff)表型性状和SSR多样性研究

以中国普通野生稻初级核心种质中广西普通野生稻部分中的 2 2 3份野生稻为材料 ,以平均分布于水稻 12条染色体上的 34对SSR引物和中国稻种资源目录中的表型性状分析广西普通野生稻SSR位点的等位变异、多样性的地理分布及不同生长习性间的多样性分布等。结果表明 ,每对引物检测到的多态性片段 7～ 4 8条 ,平均为 2 4 .91条 ,普通野生稻的等位变异数明显大于地方稻种 ,在所分析的SSR位点中杂合位点比例变化在 1.35 %～ 81.31%之间 ,平均为 32 .0 1% ,与自花授粉的栽培稻相比具有较高的杂合率 ;北纬 2 2°～ 2 3°和 2 3°～ 2 4°范围内的两个区域内(一个包括隆安、扶绥和邕宁三县 ,另一个包括象州、来宾、武宣、玉林和贵港五个县 )所包含的普通野生稻数量多 ,遗传多样性大 ,在DNA水平上是广西普通野生稻的遗传多样性中心 ,而表型性状多样性中心是在北纬 2 1°～ 2 2°和2 2°～ 2 3°,其多样性分布与DNA水平不完全一致。在 4种生长习性间 ,DNA水平上的遗传多样性大小依次为匍匐型 ,倾斜型 ,半直立型和直立型 ,表型水平的多样性与DNA水平的多样性基本一致。

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.

Identification of a Resistance Gene bls1 to Bacterial Leaf Streak in Wild Rice Oryza rufipogon Griff

Bacterial leaf streak （BLS） of rice, caused by Xanthomonas oryzae pv. oryzicola （Xoc） is a worldwide destructive disease. Development of resistant varieties is considered to be one of the most effective and eco-friendly ways to control the disease. However, only a few genes/QTLs having resistance to BLS have been identified in rice until now. In the present study, we have identified and primarily mapped a BLS-resistance gene, blsl, from a rice line DP3, derived from the wild rice species Oryza rufipogon Griff. A BC2F2 （9311/DP3//9311） population was constructed to map BLS-resistance gene in the rice line DP3. The segregation of the resistant and susceptible plants in BCzFz in 1：3 ratio （Z2=0.009, Z20 05,1=3.84, P〉0.05）, suggested that a recessive gene confers BLS resistance in DP3. In bulked segregant analysis （BSA）, two SSR markers RM8116 and RM584 were identified to be polymorphic in resistant and susceptible DNA bulks. For further mapping the resistance gene, six polymorphic markers around the target region were applied to analyze the genotypes of the BC2F2 individuals. As a result, the BLS-resistant gene, designated as blsl, was mapped in a 4.0-cM region flanked by RM587 and RM510 on chromosome 6.

Analysis on Genomic Structure Changes and Diversity of Introgression Lines in Dongxiang Wild Rice(Oryza rufipogon Griff.)

[Objective] The aim of the study was to make research on genomic struc- ture variation and variety analysis of Dongxiang wild rice. [Method] Introgression groups of BC1F6 were based on donor of Oryza rufipogon Griff. and receptor of O. sativa sp. indica Kate. Strains of 239 in the group were analyzed on Polymor- phism with the help of 25 couples of SSR primers distributed in 12 pairs of chromo- somes. [Result] Gene fragments of O. rufipogon Griff. were found penetrated in the 25 microsatellite sites and most of the groups kept the parents of Xieqinzao B or DNA sequence of O. rufipogon Griff. The average rate of recurrent homozygous bands was 78.13% in the ILs, but the highest was 94.98% （amplified by primer RM131） and the lowest was 60.25% （RM171）. The average rate of donor homozy- gous bands was 13.37%, but the highest was 32.64% （RM171） and the lowest was 2.93% （RM1095）. There were numerous heterozygous sites in the population and the average heterozygosis rate was 5.62%, while the highest was 10.04%（RM401）. Moreover, we found some parental fragments were lost and some novel fragments were not detected in either parent in BC1F6 population. The average rate of lost bands was 2.88%, while the highest was 13.39% （RM311） and the lowest was 0 （RM401）. The average rate of new bands was 1%. The average of Nei＇s gene di- versity （He） and Shannon＇s Information index （I） were 0.276 and 0.457 respectively in high generation of introgression lines. [Conclusion] The study demonstrated that distant hybridization led to extensive genetic and epigenetic variations in high gener- ation of introgression lines, which expanded the base of genetic variation and laid an important foundation for rice improvement and germplasm innovation.

Identification of a novel planthopper resistance gene from wild rice(Oryza rufipogon Griff.)

Rice planthoppers,including brown planthopper(BPH)and white-backed planthopper(WBPH),are the most destructive pests in Asian rice cultivation regions.Planthopper resistance genes that have been mapped and characterized advance our understanding of underlying resistance mechanisms and facilitate the breeding of resistant varieties,thereby contributing to an efficient pest management strategy.In this study,a novel resistance gene Bph38 derived from the wild rice species Oryza rufipogon Griff.was found to confer high resistance to BPH and WBPH.Conventional mapping was performed to identify regions associated with BPH and WBPH resistance,and two mapping efforts led to the same region on chromosome 4 flanked by markers RM16563 and RM16763.Bulked-segregant analysis and next-generation sequencing were performed using the same population to detect the resistance gene.Conventional mapping narrowed the region to a 12.3-Mb segment,and fine mapping using BC1 F2 recombinants identified a 79-kb segment flanked by markers YM112 and YM190.Near-isogenic lines(NILs)carrying Bph38 in the 9311(indica)and BR54(japonica)genetic backgrounds were developed by crossing and backcrossing with marker-assisted selection.The agronomic traits and BPH and WBPH resistance of the NILs were similar to those of the recurrent parents.Mandatory feeding and host-choice tests revealed that Bph38 showed both antibiotic and antixenotic effects in both insects,with stronger effects in indica-background lines.Further fine mapping and characterization of the major gene may result in map-based cloning of the gene and allow its application in breeding insectresistant rice varieties.

Genetic diversity of Oryza rufipogon Griff. in Hainan Province analyzed by ISSR and SSR markers

Assessment of genetic diversity is an essential component in germplasm characterization and conservation.There are three wild rice species in Hainan Province,including Oryza rufipogon Griff.In order to detect the genetic diversity of different populations of Oryza rufipogon in Hainan,ISSR(inter-simple sequence repeat)and SSR(simple sequence repeat)markers were used to investigate 180 accessions from six localities in Hainan.Fourteen ISSR primers amplified 185 alleles with 171(92.43%)polymorphic,the number of alleles ranged from 8 to 17,with an average of 13.14 alleles per locus.Thirty-eight pairs of SSR primers used in this study amplified 213 alleles with 190(89.20%)polymorphic,the number of alleles ranged from 2 to 14,with an average of 5.66 alleles per locus.Both ISSR and SSR analyses revealed a high level of genetic diversity in the wild populations.The population with the highest genetic diversity is Wanning(WN),and the population with lowest genetic diversity is Wenchang(WC).The results of a UPGMA cluster using the NTSYS program showed that each population has a low degree of genetic differentiation.Furthermore,the Mantel test revealed that the genetic similarities detected by ISSR and SSR were significantly correlated(r=0.8634,t=93.67)when detecting genetic diversity at the species level.The two molecular marker systems were able to determine the genetic diversity among Oryza rufipogon,and the two groups of indexes obtained by using the two markers have a high level of consistency.

马来西亚番荔枝科紫玉盘属(Uvaria Linn.)、杯冠木属(Cyathostemma Griff.)和 Ellipeia Hook. f. et Thomson叶的比较解剖学(英文)

对紫玉盘属８种，杯冠木属３种和Ｅｌｌｉｐｅｉａ属 １种进行了叶的比较研究，以调查不同种之间解剖 学的不同点，这对种的鉴别和了解它们的分类学意义可能是有用的。有意义的解剖学特征是：末端石细 胞，表皮细胞的晶簇，毛状体，在中脉和叶柄的薄壁组织内的短石细胞以及中脉和叶柄横切面的形状。 有某些特征仅出现在某些种中，这对种的鉴别是有用的。结果亦显示这三个属的联系十分紧密。

利用SSR标记分析普通野生稻遗传多样性

【目的】揭示中国云南景洪、云南元江、江西东乡、缅甸普通野生稻(OryzarufipogenGriff.)遗传多样性,以及云南景洪和元江普通野生稻原、异位保存下变异情况。【方法】利用36对SSR标记对来自云南景洪异位保护与原位保护区、云南元江异位保护与原位保护区、江西东乡及缅甸共102份普通野生稻进行检测,开展不同地理来源及不同保存方式下普通野生稻居群遗传多样性比较与聚类分析。【结果】供试普通野生稻检测出等位变异(Na)110个,平均3.056个,变幅为1~5个;Nei's基因多样性指数(I)平均为0.448。不同地理来源Nei’s基因多样性指数大小为:缅甸(0.561)>云南景洪(0.437)>云南元江(0.236)>江西东乡(0.230),云南景洪和元江的普通野生稻Nei’s基因多样性指数均表现为异位保护区大于原位保护区(云南景洪:0.498>0.131,云南元江:0.264>0.035)。聚类与遗传分化分析显示,供试材料平均遗传相似系数为0.772,变幅0.260~1.000;在遗传相似系数0.635处可将供试材料划分为云南景洪、云南元江、江西东乡及缅甸居群。云南景洪原位保护区与缅甸的普通野生稻遗传距离较近(0.560),云南元江原位保护区与江西东乡的普通野生稻遗传距离较近(0.552);而云南元江原位保护区与景洪原位保护区的普通野生稻遗传距离为0.748,表明云南元江和景洪普通野生稻有明显的遗传分化。【结论】不同地区的普通野生稻遗传分化有明显的地域性,云南景洪和元江普通野生稻遗传多样性因原生境居群减少而下降。

利用东乡普通野生稻染色体片段置换系鉴定抗穗发芽QTL

【目的】高温阴雨天气导致水稻生产田出现穗发芽(Pre-harvest Sprouting,PHS),种子活力降低,严重影响水稻产量与品质性状。鉴定筛选抗穗发芽种质及基因资源是培育抗穗发芽水稻新品种、消除稻谷穗发芽产生危害的根本途径。【方法】以强休眠、不易穗发芽的东乡野生稻‘C35’为供体亲本、较易穗发芽的‘日本晴’(NIP)为受体亲本构建的染色体片段置换系(CSSLs)群体为试验材料,于2021—2023年进行抗穗发芽特性鉴定评价,筛选抗穗发芽种质和鉴定主效QTL。【结果】不同环境下东乡野生稻‘C35’休眠性较强、穗发芽率均为0.00%,‘日本晴’存在明显穗发芽现象、穗发芽率均值为31.95%;CSSLs穗发芽率变幅较大,不同年份穗发芽率表型重复性较好,筛选到10份强休眠、抗穗发芽的种质;共检测到14个控制穗发芽率QTL,4个QTL在不同环境下被重复检测到,相关QTL在染色体上形成qPHSRC1、qPHSRC2、qPHSRC8和qPHSRC9等4个QTL簇,其中主效QTL簇qPHSRC2和qPHSRC9的LOD值、表型贡献率和加性效应值较大,qPHSRC2为新发现的主效QTL簇。【结论】鉴定筛选出一批抗穗发芽的种质材料,定位到14个抗穗发芽QTL,筛选出4个重复性较好的QTL簇,发现1个调控穗发芽率的新主效QTL簇qPHSRC2。

中国普通野生稻初级核心种质取样策略

以国家品种资源库编目入库的中国普通野生稻种质 5 5 71份为材料、19个分类和形态性状的数据比较研究了中国普通野生稻的核心种质总体取样比例和取样策略 ,以获得最佳初级核心种质。设 3个总体取样比例 5 %、15 %和 2 5 % ,取样方案分 3个层次即分组原则、组内取样比例和组内取样方法。分组原则为省、纬度、生长习性和单一性状及不分组的大随机 ;组内取样比例为对数法、平方根法、遗传多样性指数和简单比例法 ;组内取样采用随机和聚类 2种方法。结果表明 ,当总体取样比例从 5 %增加到 15 %时 ,所取得核心种质的表型保留比例有比较大的增幅 ,而比例由 15 %增加到 2 5 %时 ,表型保留比例变化不大 ,因此认为 15 %的取样比例较为合适 ;取样方案以采集省份分组 ,组内以对数比例法聚类取样效果最好。最终根据这一方案在计算机上编程取样 86 0份 ,其多样性指数为1.10 15、变异系数为 16 .87,表型方差为 0 .85 4 6。 3个检测参数值比原始种质库都有明显的提高。此外 ,根据国家种质资源库表型数据人工定向取样 6 0份 ,建立了 92 0份材料的中国普通野生稻初级核心种质。

中国野生稻的现状调查

中国有三种野生稻。野生稻是栽培水稻的野生近缘种，已被列为濒危植物［７］，它们分布于中国南方８个省（区）的热带、亚热带湿热生境中。近年来人为的干扰和生境的破坏已导致它们的居群大量绝灭，其中濒危程度最高的是普通野生稻。本文阐述了它们的生物学、生态学特性，研究了它们的群落学特征，初步报道了它们的濒危状况。

东乡野生稻等位酶位点遗传多样性的初步研究

采用聚丙烯酰胺凝胶电泳技术 ,对东乡野生稻 9个天然小群体进行了 15个等位酶位点的遗传多样性分析。结果表明 ,东乡野生稻具有较高的遗传变异水平 ,9个小群体的多态位点百分率 (P)为 2 8.2 % ,等位基因平均数 (A)为 1.30 6 ,预期杂合度 (He)为 0 .2 34;小群体间的分化程度不高 ,基因分化系数 (Gst)为 0 .0 12 ,等位酶测定的总变异中 ,1.2 %来自小群体间 ,其余的变异 (98.8% )来自小群体内。

中国普通野生稻的原始型及其是否存在籼粳分化的初探

选用国内７省（自治区）５７１份，国外２７份普通野生稻编号根据１０个形态性状进行聚类分析并结合同工酶分析与野生稻原产地生态考察将中国普通野生稻划分为多年生和一年生两群共７个类型。提出中国存在一年生普通野生稻及原始型普通野生稻问题，并根据同工酶４个基因位点分析对中国普通野生稻是否存在籼粳分化问题进行了讨论。

桂东南地区普通野生稻遗传多样性研究

利用25个微卫星位点对广西壮族自治区贺州、崇左、防城港3市8个居群301份普通野生稻材料的遗传多样性和遗传结构进行研究,结果表明桂东南地区普通野生稻遗传多样性丰富,平均等位基因数A=10.2400,有效等位基因数Ae=5.0221,平均期望杂合度He=0.7641,实际观察杂合度Ho=0.4840。根据固定指数(F=0.5653)计算出的异交率(t=0.2777)表明,普通野生稻的繁育系统是典型的混合繁育系统。对其遗传结构分析表明,总的遗传变异中有34.59%存在于居群间(Fst=0.3459)。进一步研究发现大多数居群偏离了Hardy-Weinberg平衡且杂合体不足(Fis=0.2680,Fit=0.4817)。最后根据各居群的遗传变异特点和遗传多样性比较,建议居群QT、YJ和TJ需要优先保护。

普通野生稻东乡群体等位酶水平的遗传多样性研究

利用普通野生稻东乡群体苗期幼叶 ,采用聚丙烯酰胺凝胶电泳技术 ,对采自异位种质圃内 9个小群体的材料进行研究。选取 12种酶系统进行等位酶分析 ,共获得 2 1个等位酶位点。对这 2 1个位点等位基因的统计分析表明 :普通野生稻东乡群体多态位点的百分数为P =2 3 3% ,等位基因平均数为A =1 16 6 ,观察杂合度为Ho=0 14 8,预期杂合度为He=0 0 89,固定指数F =- 0 6 6 0 ,基因分化系数GST=0 0 15。以上数据表明 :普通野生稻东乡群体偏离Hardy Weinberg平衡 ,小群间的遗传分化很小 ,遗传多样性主要存在于小群体内的单株间。

广东高州普通野生稻与粳稻杂交F_1花粉育性及其发育特点

以粳稻台中65为母本，高州普通野生稻141个编号材料为父本，成功组配72个粳野杂种F1，分别对杂种F1的结实率、花粉育性及其发育特点进行研究。结果发现，粳野杂种F1平均结实率为68.30％，变化范围为30.29％～94.05％，大部分在50％～80％之间；花粉平均育性为76.49％，最低为33.23％，最高为95.72％，大部分都高于70％，表现正常。花粉败育类型包括染败、典败、圆败和大小花粉粒；花药的平均裂药指数为3.87，接近正常。粳野杂种F1花粉发育过程与栽培稻基本一致，可分为8个时期，包括小孢子母细胞形成期、小孢子母细胞减数分裂期、小孢子早期、小孢子中期、小孢子晚期、二胞花粉早期、二胞花粉晚期和成熟花粉期。研究结果表明广东高州普通野生稻可能具有决定杂种F1花粉育性的不同基因，包括花粉不育中性基因等。

利用SSR标记分析海南普通野生稻的遗传多样性

选用平均分布于水稻基因组的28对SSR引物,对海南不同纬度5个普通野生稻居群的163份材料进行遗传多样性和遗传结构研究。结果表明:(1)海南普通野生稻具有较高的遗传多样性,28个位点共检测到227个等位变异,平均等位变异数A=8.1071,有效等位变异数Ae=4.4190,平均期望杂合度He=0.4004,实际观察杂合度Ho=0.7062,香农指数I=1.6048;(2)居群的遗传分化系数较大,总的遗传变异中有46.40%存在于居群间(Fst=0.4640);(3)居群内杂合体较高(F is=-0.7069),根据固定指数(F=0.0588)计算出的异交率t=0.8889,说明海南普通野生稻的繁育系统属于一种较高的异交混合交配类型。