粳稻资源热粳35遗传图谱构建与耐热QTL分析

为了揭示耐热粳稻资源热粳35的遗传特性,以热粳35/协B F2群体为研究材料,构建了包含140个SSR标记的分子图谱;借助构图分子数据分析标记基因型的分离情况,并进行耐热性QTL分析。结果表明,该图谱覆盖基因组全长2 157.7 c M,标记间平均图距15.4 c M,45个(28.5%)标记极显著偏向亲本或杂合子(P0.01)。在第1、第3、第4、第6、第7和第8号染色体上发现9个偏分离热点区域。其中,有4个偏分离热点区域可能与孢子体或配子体选择有关,在第4、第8和第12号染色体上共检测到3个耐热性QTL。本研究结果为耐热粳稻资源的遗传机理解析和新品种选育提供了参考信息。     

小麦杂种优势群研究：I.利用RAPD标记研究小麦品种间遗传差异

选用我国的３８个冬小麦品种（系）和２个加拿大春小麦品种（系），利用ＲＡＰＤ标记进行小麦基因型之间分子标记遗传差异研究，探讨分子标记在建立小麦杂种优势种中的应用。利用５９个随机引物对４０个小麦基因型ＰＣＲ扩增结果表明，其中２９个引物（占４９％）扩增产物经琼脂糖凝胶电泳分离表现多态性，这２９个引物共扩增出１６８条带，其中７８条带（占４６．６％）具有多态性，每个引物可扩增１￣６条多态性带，平均２．７条带     

基于InDel标记的谷子株高QTL定位

插入/缺失（InDel）标记在植物基因组中广泛分布,然而谷子中InDel标记的数量十分有限。为挖掘InDel位点和开发分子标记,本研究基于衡谷12号和长农35号的深度重测序结果,分析其单核苷酸多态性（SNP）、InDel和结构变异（SV）。利用JoinMap 4软件构建连锁遗传图谱,利用WinQTLCart 2.5软件定位株高数量性状位点（QTL）,利用生物信息学、测序和实时荧光定量PCR(qRT-PCR)进行候选基因分析。研究表明,3种变异类型数量由多到少排序为SNP>InDel>SV;获得1 392个在衡谷12号和长农35号中具有多态性的InDel标记,多态性率为35.14%,这些标记在谷子9条染色体上分布不均;获得一张包含467个InDel标记的谷子遗传连锁图谱,该图谱总图距448.45 cM,平均图距0.96 cM;利用F2群体定位了4个株高QTL(qPH5-1、qPH5-2、qPH9-1和qPH9-2),进一步利用重组自交系（RIL）群体对其中2个效应值较大的QTL(qPH5-1和qPH9-2)进行验证,结果重新检测到qPH9-2,似然比的自然对数（LOD）值为9...     

中国板栗SSR标记的研究

本研究从中国板栗“艳红”中分离到25个SSR标记。为了鉴定SSR位点，在重复序列的两侧侧翼序列设计引物，并通过化学荧光检测法对6个板栗样品进行检测，共检测到18个多态性位点，每个位点的等位基因数为2~6个。挑选12个位点，通过半自动系统ABI PRISM 377对中国北方24个板栗品种进行分析，这12个标记显示了高达共75个等位基因的遗传多态性，每个位点的等位基因为4~10个，平均为6.3个，预期的平均杂合性为0.743（介于0.680~0.845），检测到的平均杂合性为0.829（介于0.730~0.930）。无效等位基因估算频率显示为3个位点的正向价值，除了一个位点外，这些价值都很低，鉴定机率为7.01×10-11，亲缘关系鉴定机率非常高，为0.999，足够用于花粉流的研究。     

我国部分冬小麦新品种（系）SSR标记遗传差异的研究

本研究利用53对SSR引物对全田1999－2000年北方冬麦区及黄淮冬麦区观察圃中选出的48个新品种（系）进行遗传差异研究，共检测出58个SSR位点上的367个等位变异，平均每个位点有6.33个等位变异，其中B组每个位点的等位变异最多，这表明B基因组化更快，分化更大。48个品种（系）在全基因组及A、B、D基因组聚类结果表明这些品种的相似系数聚类的范围较小，为0.75－0.98。全基因组聚类结果与品种的系谱来源及育成地区相吻合。研究结果表明我国冬小麦品种的种质基础相对较狭窄。加强不同来源种质的利用和特异亲本类型的培育对我国冬小麦遗传改良非常重要，利用5个多态性高的SSR标记就可以将这48个小麦新品种（系）区分开，每个品种（系）都有各自独特的指纹图谱。     

小麦赤霉病抗源望水白的QTL定位

236对SSR引物中共有74对在小麦（Tritium aestivum）抗、感亲本之间有多态性,多态性频率达31.7%.对小麦望水白/安农8455群体的SSR分析表明,在2年资料中都出现的与抗小麦赤霉病（Fusarium head blight）连锁的SSR标记有14个,主要分布在染色体3B和2A上.利用Map Manager QTX软件构建连锁图和QTL定位,有38个标记主要分布于5条染色体上（3B、2A、5A、6B和7B）;根据3年的抗性资料分析,3B上的QTL分别位于XBarc133～Xgwm389、XBarc133～Xgwm389和Xg-wm533.1～Xgwm493之间,LOD为2.58、6.49和2.45,分别能解释10%、23%和9%的表型变异.2001年和2003年的抗性资料分析表明,2A上存在2个抗性QTL,都位于Xgwm95～Xgwm372之间,LOD分别为2.82和2.93,均能解释11%的表型变异.     

水稻籼粳交DH群体的构建及其基因型偏态分离分析

长江大学农学院, 荆州 430025)摘要：对籼粳杂交组合"中花11（粳）/中组14（籼）"F1进行花药培养,获得112个二倍体再生植株。利用亲本间多态性SSR分子标记对该群体二倍体再生植株进行纯合性鉴定,并分析该群体基因型偏离情况。选用22个多态性标记分析结果表明,所得再生植株都为来自花粉母细胞的纯合植株,不存在来自于体细胞的杂合株,确保了DH群体的准确性。多态性SSR带型分析结果表明,该群体未发生异常的基因型偏态分离。因此,在组织培养体系中引进SSR标记,快速准确稳定了DH群体,基因型偏态分离分析保证了群体的质量,为后续的图谱构建及基因定位工作奠定了基础。     

四川小麦品种贮藏蛋白位点及SSR分析*

利用种子贮藏蛋白和SSR标记研究了四川近20多年育成的小麦(Triticum aestivum)品种第1和第6同源群染色体的蛋白基因位点及遗传多样性。结果表明：供试的47个小麦品种共检测出47条醇溶蛋白条带，其中39条具有多态性，占82．98％；高分子量(HMW)谷蛋白亚基共出现7种亚基和11种亚基组合，表明四川主栽小麦品种在醇溶蛋白位点上存在广泛的变异，而HMW谷蛋白亚基遗传基础较狭窄。SSR结果表明，在21个位点中有8个(38．1％)位点具多态性，共检测到19个等位变异，供试品种在：DNA水平上存在一定的变异。聚类分析表明：两种标记均可将供试品种(包括中国春)分为三大类。通过Mantel检测，两种标记的分析结果间有显著的相关性，反映了在蛋白质和DNA水平上的结果可以互相补充，增加可靠性。     

高能混合粒子场辐照小麦M_1代变异的SSR分析

本试验利用北京正负电子对撞机直线加速器E2束流打靶产生高能次级混合粒子场,模拟次级宇宙射线,分别以0、109、145、195、284和560Gy剂量处理两个冬小麦品种ZY9和ZH7,并与相同剂量的60Coγ射线相比较,研究混合粒子场辐射处理对小麦幼苗生长和微卫星(SSR)标记谱带变化的影响。试验结果表明,随着混合粒子场处理剂量的增加,小麦幼苗生长受到的损伤逐渐增加。SSR标记分析结果发现,小麦B基因组的多态性位点频率占总多态性频率的46%,在3个基因组中最高,可能为“热点”突变基因组。高能混合粒子场对冬小麦幼苗的生长抑制和微卫星DNA的损伤效应大于γ射线。     

小麦粘类CMS育性恢复基因的SSR分子标记与定位

利用SSR技术,对小麦粘类CMS（细胞质雄性不育）的1对近等基因系（NILs）和回交群体（BC₁'）进行分析,筛选与粘类CMS育性恢复基因相连锁的分子标记并进行恢复基因定位,以进一步探讨小麦粘类CMS育性恢复的遗传机理。结果表明：在18对位于1BS上的SSR引物中,有6对引物在近等基因系间扩增出了稳定的多态性差异;经分离群体验证表明,恢复基因与4对SSR引物的扩增位点Xwmc406、Xbarc8、Xwmc611和Xgwm273有连锁关系,遗传距离分别为2.7、2.8、21.4和26.2cM,这些标记可稳定应用于小麦粘类CMS育性恢复基因的辅助选择;研究还表明,小麦粘类雄性不育系的育性恢复主要受1BS上的1对主效恢复基因及一些微效基因共同控制;本研究标记出的恢复基因应为Rfv1;上述4个标记与该主效恢复基因Rfv1之间的位置顺序依次为Xwmc406、Rfv1、Xbarc8、Xwmc611、Xgwm273。     

Genetic diversity in wild and cultivated black raspberry (Rubus occidentalis L.) evaluated by simple sequence repeat markers

Breeding progress in black raspberry (Rubus occidentalis L.) has been limited by a lack of genetic diversity in elite germplasm. Black raspberry cultivars have been noted for showing very few phenotypic differences and seedlings from crosses between cultivars for a lack of segregation for important traits. Despite these challenges, little molecular work has been done to explore genetic diversity and relationships in wild and cultivated black raspberry germplasm. Microsatellite, or simple sequence repeat (SSR), markers are highly polymorphic codominant markers useful for studying genetic diversity, population genetics, genetic fingerprinting and other applications. We examined genetic diversity in 148 wild and cultivated black raspberry accessions using 21 polymorphic SSR markers. Black raspberry cultivars clustered tightly and showed higher than expected heterozygosity while that of wild accessions was low. Relationships between wild black raspberry accessions were poorly resolved and regional clusters were mostly absent from our analysis. Our results indicated that wild black raspberry germplasm is a relatively untapped resource available for future breeding.     

Molecular genetic diversity analysis in emmer wheat (Triticum dicoccon Schrank) from India

Emmer wheat (Triticum dicoccon Schrank) is still largely cultivated in India, and highly appreciated for the preparation of traditional dishes. Moreover, its nutritional characteristics could justify a development of its cultivation. The perspective of genetic improvement however requires a good knowledge of the genetic diversity existing within the eco-geographic group of Indian emmer wheats. A set of 48 emmer wheat accessions from India including 28 from a local collection and 20 Indian accessions obtained from CIMMYT, Mexico, was assessed for genetic variability using 47 microsatellite (SSR) markers, distributed over all the 14 chromosomes. The number of alleles per locus ranged from 2 to 9, with an average of 3.87 alleles per locus. A total of 201 alleles were detected at 52 loci with average polymorphic information content of 0.35 per locus and a mean resolving power of 1. The pair-wise similarity coefficients calculated from binary data matrix based on presence or absence of alleles varied from 0.15 to 0.98, but was greater than 0.5 for most accessions, indicating a high level of similarity. A cluster analysis based on the similarity matrix identified nine distinct accessions and three clusters. All the recently developed commercial varieties were distinctly different from the clusters. Based on the analysis, it appears that Indian emmer wheats are not very diverse. Consequently, there is a need to increase the diversity within the Indian emmer wheat eco-geographic group, by introducing diversity from other eco-geographic groups, or even from other wheat species.     

Analysis of genetic diversity of soybean germplasm from five different origins using RAPD markers

The pattern of genetic diversity among 92 genotypes of soybean from 5 different origins/sources (Pakistan, the USA, Asian Vegetable Research Development Centre (AVRDC), Japan and North Korea) was analyzed using randomly amplified polymorphic DNA markers. Out of 20 random primers 6 tested, 10 were polymorphic among genotypes and they yielded 107 markers, with an average of 10.7 markers per primer. The proportion of polymorphic bands within genotypes ranged from 0.47 to 0.71 with an average of 0.59. Pakistani and US genotypes exhibited the highest number of polymorphic bands (95%), while North Korean genotypes revealed the lowest (60%). The mean band frequency of the primers among genotypes was 0.57 with a range of 0.08–0.99. The Shannon’s index and Nei’s genetic diversity index revealed that primer OPF-06 showed maximum genetic diversity among the genotypes. Dendrogram constructed using Unweighted Pair Group Mean Average (UPGMA) method divided the genotypes into 5 main groups consisting of 13 clusters. The results of cluster analysis indicated that the genetic diversity between Pakistani and US or AVRDC genotypes is much larger than that between Pakistani and North Korean or Japanese genotypes. The Pakistani genotypes had distinct bands from plant introductions. Therefore, the Pakistani genotypes may be useful to soybean breeders.     

Genetic diversity of Pakistan wheat germplasm as revealed by RAPD markers

Wheat breeding in Pakistan started in 1930s before partition in the United India and so far has released more than 68 cultivars, but no systematic analyses of the genetic diversity of Pakistan wheat have been made. Twenty Pakistan wheat cultivars released from 1933 to 2002 were examined for genetic diversity and relationships using random amplified polymorphic DNA (RAPD) markers. Forty-two RAPD primers were applied and 184 polymorphic bands were generated for each cultivar. Most of the cultivars were genetically interrelated, although six of them displayed some genetic distinctness. The RAPD variation observed among these cultivars was low. Only 40.7% of the total scorable bands were polymorphic, and 26.1% of the polymorphic bands were observed most frequently (f = 0.95) among the 20 cultivars. The proportions of polymorphic bands for each cultivar ranged from 0.67 in ‘Yecora’ to 0.84 in ‘C-250’ with an average of 0.76. About 1.4% of the RAPD variation might have been fixed over the 69 years of wheat breeding, but such fixation was not statistically significant. These results are significant for future improvement and conservation of Pakistan wheat.     

Analysis of genetic diversity in Tunisian durum wheat cultivars and related wild species by SSR and AFLP markers

Thirty-four durum wheat cultivars representing the Tunisian durum (Triticum durum Desf.) wheat collection and seven wild species of wheat relatives (Triticum turgidum L., T. dicoccon Schrank., T. dicoccoides (Körn) Schweinf., T. araraticum Jakubz., T. monococcum L., Aegilops geniculata Roth, and Aegilops ventricosa Tausch) were analysed with amplified fragment length polymorphism (AFLP) and microsatellite (SSR) markers. Both marker systems used were able to differentiate durum wheat cultivars from the wild relatives and to specifically fingerprint each of the genotypes studied. However, the two marker systems differed in the amount of detected polymorphisms. The 15 SSR markers were highly polymorphic across all the genotypes. The total number of amplified fragments was 156 and the number of alleles per locus ranged from 3 to 24 with an average of 10.4. Two SSR markers alone, Xwms47 and Xwms268, were sufficient to distinguish all 34 durum wheat genotypes. The five AFLP primer pair combinations analysed yielded a total of 293 bands, of which 31% were polymorphic. The highest polymorphic information content (PIC) value was observed for SSRs (0.68) while the highest marker index (MI) value was for AFLPs (7.16) reflecting the hypervariability of the first and the distinctive nature of the second system. For durum wheat cultivars, the genetic similarity values varied between 31.3 and 81% for AFLPs (with an average of 54.2%), and between 3.6 and 72.7% for SSRs (with an average of 19.9%). The rank correlation between the two marker systems was moderate, with r = 0.57, but highly significant. Based on SSR markers, highest genetic similarity (GS) values were observed within the modern cultivars (37.3%), while the old cultivars showed a low level of GS (19.9%). Moreover, the modern cultivars showed low PIC and MI values. UPGMA Cluster analysis based on the combined AFLP and SSR data separated the wild wheat species from the durum wheat cultivars. The modern cultivars were separated from the old cultivars and form a distinct group.     

Genetic Variation Among Portuguese Landraces of ‘Arrancada’ Wheat and <Emphasis Type="Italic">Triticum petropavlovskyi</Emphasis> by AFLP-based Assessment

Portuguese wheat landraces, ‘Arrancada’ were collected from the Aveiro region, Portugal before the 1950s. We found in eight accessions of `Arrancada' hexaploid wheat with the long glume phenotype. We assessed the comparative genetic diversity among Portuguese `Arrancada' wheat and Triticum petropavlovskyi Udacz. et Migusch. using AFLP assays and discuss the origin of long glumed `Arrancada' wheat. With the four primer pairs a total of 4885 visible bands were scored corresponding to 99 AFLP markers as putative loci, of which 55 markers (54%) were polymorphic. UPGMA clustering and PCO grouping showed that long glumed ‘Arrancada’ wheat and T. petropavlovskyi were genetically diverse. Long glumed ‘Arrancada’ hexaploid wheat separated into two clusters (groups) in both the UPGMA dendrogram and in PCO analysis. Four long glumed accessions fell in the cluster of tetraploid wheat. A similar argument could be made for another four accessions which belong to the cluster of hexaploid wheat. The substantial level of genetic variation indicated that long glumed ‘Arrancada’ wheat and T. petropavlovskyi originated independently. It is most likely that the P-gene of long glumed ‘Arrancada’ hexaploid wheat was introduced from T. turgidum ssp. polonicum (L.) Thell. to T. aestivum via natural introgression or breeding. We suggest that the long glumed ‘Arrancada’ hexaploid wheat did not originate from T. aestivum through spontaneous mutation at the P locus