干尖线虫病对不同水稻品种（系）产量相关性状的影响

[目的]该研究旨在了解干尖线虫病对不同水稻品种的影响。[方法]通过田间表型观察与室内考种试验，对自然发病状态下的4个常规粳稻品种（系）和粳稻恢复系 R161进行了观察和分析。[结果]不同水稻品种（系）被侵染后的症状存在差异，常规粳稻宁1707、宁1818、镇稻88和南粳9108被侵染后表现"干尖"和"小穗头"症状，粳稻恢复系R161只表现"干尖"，不表现"小穗头"症状，且"干尖"的位置不同，分别位于剑叶叶尖，整片剑叶及倒二叶。供试材料被水稻干尖线虫侵染后均能抽穗，但是株高、穗长、结实率和千粒重均受到不同程度的影响。此外，R161被干尖线虫侵染后，不同发病部位对水稻产量的影响不同，整片剑叶干枯扭曲的稻穗受影响最大。[结论]该研究为进一步阐明我国水稻干尖线虫病的危害规律和制定相应的防治措施提供依据。     

甜高粱主要农艺性状的主成分分析

对国内外194份甜高粱品种进行了10个主要农艺性状调查。采用主成分分析,发现穗重、生育期、生物产量、穗长、茎粗、分蘖及含糖量等7个因子为农艺性状的主成分。在甜高粱育种中应加强生物产量选择,适当考虑含糖量及生育期,但穗重、分蘖和茎粗不宜过高,并且穗长越短越好。研究结果将为甜高粱的品种改良和创新提供理论依据。     

Multivariate analysis and genetic diversity for morphometric and root textural quality traits in ashwagandha (Withania somnifera Dunal)

Ashwagandha (Withania somnifera) is an important medicinal plant and its dried roots are used in traditional systems of medicine. The market price of roots is determined by physical (textural) quality. Brittle roots with high starch and low fiber are considered to be superior because of ease in grinding. Genetic diversity studies based on root textural parameters have not been done so far. So the present study was designed to assess genetic diversity for morphometric traits and root textural quality parameters among two morphologically distinct groups: Poshita and Nagore. The PCA separated the morphometric and root texture variables distinctly into two different principal components: PC-1 and PC-2 respectively, indicating that both are negatively associated. All the morphotypes in Poshita group showed high positive loadings in PC-1 indicating that component genotypes are high root yielding. Nagore morphotypes were low yielding but the root texture was good. Clustering of morphotypes grouped Poshita and Nagore separately with high inter-cluster distances indicating that both groups are highly divergent from each other, suggesting that there is sufficient scope for varietal improvement through hybridization.     

小麦根腐镰刀菌鉴定及其生物学特性

１９９１－１９９４年对山东省１１县市的小麦根腐病标样进行病原分离培养及致病性测定，鉴定出６种镰刀菌，有黄色镰刀菌（Ｆｕｓａｒｉｕｍ ｃｕｌｍｏｒｕｍ（Ｓｍｉｔｈ Ｓａｃｃ）、禾谷镰刀苏（Ｆ ｇｒａｍｉｎｅａｒｕｍ Ｓｃｈｗ）、尖孢镰刀苏（Ｆ ｏｘｙｓｐｏｒｕｍ Ｓｃｈｌ）、串珠镰刀苏（Ｆ ｍｏｎｉｌｉｆｏｒｍｅ Ｓｈｅｌｄ）茄病镰刀苏（Ｆ ｓｏｌａｎｉ（Ｍａｒｔ） Ｓａｃｃ）及木贼镰刀菌（Ｆ ｅｑ     

Fat-Tailed Sheep Traits as Affected by Docking

The literature mostly indicates that docking fat-tailed lambs initially reduces growth but that post-weaning growth and feed conversion efficiency then increase. The amount of fat deposited, the total separable lean meat to fat ratio and the meat quality all increase, while the percentage of bone in the carcase either decreases or does not change in the carcases of the docked lambs. Wool growth and characteristics are, in general, not affected and reproductive traits in ewes and lambs are improved by docking. The rectal temperature, respiration rate and pulse rate are decreased following docking. The concentrations of immunoreactive beta-endorphin and cortisol in the plasma and the incidence of foot stamping and restlessness, as indicators of stress, increase after docking. Other constituents of the blood are not significantly altered following docking or by the methods of docking. Docking of fat-tailed sheep using rubber rings at one day of age can be recommended. This revised version was published online in July 2006 with corrections to the Cover Date.     

微卫星标记与丝羽乌骨鸡产蛋性能的关系研究

从鸡的遗传图谱中选择9个与产蛋性能相关的微卫星基因座,对在产蛋性能上有明显差异的丝羽乌骨鸡个体共170只进行标记基因型与产蛋性状的最小二乘分析,结果表明：有4个标记G31913、X82867、Z95315、G01672与丝羽乌骨鸡的4个月连产蛋量、开产蛋重及500日龄产蛋量间存在显著的关系。标记G31913中基因型AB所对应的开产体重最小二乘均值与其它基因型的对应值间的差异达显著或极显著,开产蛋重间无显著差异。标记Z95315的基因型CC所对应开产蛋重、开产体重最小二乘均值最高,并且均显著高于其余8种基因型所对应的开产蛋重、开产体重最小二乘均值。标记G01672基因型为EE、AE所对应开产蛋重最小二乘均值与基因型为CE、CC的对应值间差异显著;等位基因E与开产蛋重有显著正相关,等位基因C与开产蛋重有显著负相关。标记X82867基因型CD所对应500日龄产蛋量最小二乘均值显著低于AB型,4个月连产蛋量、300日龄产蛋量也低于基因型为AB个体。研究表明,标记G31913的基因型AB和标记Z95315的基因型CC有望作为开产蛋重、开产体重早期选择的辅助标记。     

鸡GDF-5基因外显子1多态性与鸡骨骼发育性状的相关研究

根据GenBank发表的鸡GDF-5基因的mRNA序列设计引物，以白耳鸡和东北农业大学选育的肉鸡高、低腹脂系第8世代鸡群为试验材料，通过测序和PCR-SSCP的方法进行SNP检测和基因型分析，探讨GDF5基因多态性与鸡生长和骨骼发育性状之间的关系。结果发现在GDF-5基因外显子1的84bp处存在1个C／T的突变位点，对该突变位点在研究群体中进行基因型分析，结果产生3种基因型，AA型个体的基因序列和GenBank（Accession No：AF123389）中的一致为C，而BB型个体的基因序列在84bp处突变为T。基因型与鸡体组成性状的统计分析结果表明，AA基因型个体的跖骨围显著高于AB基因型个体（P〈0．05）；AA基因型和AB基因型个体的跖爪重和跖爪率显著高于BB基因型个体（P〈0．05）；AB基因型个体的股骨长和股骨重显著高于BB基因型个体（P＜0．05）；表明该基因对鸡的骨骼性状有较大的影响或与控制骨骼发育性状的主效基因相连锁。     

MC4R基因主效位点在中外猪种中的遗传多样性及其与生长肥育性状的关联性分析

采用PCR-TaqI-RFLP技术,检测了9个中国地方猪种、3个外来猪种和1个培育猪种的612个个体及白色杜洛克×二花脸资源家系418头F2个体在MC4R基因D298N主效位点的遗传变异,统计分析了MC4R基因型与日增重、腹脂率及肩、胸、腰、臀部膘厚等生长肥育性状的关联性。结果表明:(1)G等位基因在中国地方猪种、长白和杜洛克中呈高频分布,而大白和南昌白猪具有高频率的A等位基因;(2)GG基因型个体的胸、腰、臀部膘厚较AA基因型和AG基因型个体厚,GG基因型个体的240日龄重、至240日龄平均日增重大于AA基因型个体,GG基因型个体的腹脂率高于AA基因型个体,差异显著。试验结果进一步验证了MC4R基因对猪生长肥育性状的影响效应。     

蟛蜞菊对肉兔的饲用价值

选择24只体重相近的40日龄肉兔,随机分成2组,每组12只,基础日粮相同,青饲料分别饲喂桂牧1号象草与蟛蜞菊,两组在平均日增重、平均日耗基础料量、平均日耗青料量间均无显著差异(P>0.05),表明肉兔采食蟛蜞菊可正常生长发育。同时,两组肉兔的血液指标和内脏重量无显著差异,表明蟛蜞菊与桂牧1号的饲用价值相似,可用于肉兔生产。