利用MAS技术改良四个水稻恢复系及其抗病性分析

水稻白叶枯病作为世界范围内的水稻三大病害之一,给水稻的生产带来了严重的损失。培育抗病品种是解决水稻抗病性的主要措施。目前国内的杂交水稻携带的抗性基因普遍单一,长期大规模推广的情况下容易造成抗性的丧失从而引起某种病害的大爆发。因此,拓宽抗谱,增强抗性并且抗性持久是今后水稻育种的主要方向之一。实验表明,将不同来源的抗性基因通过杂交或者转移聚合到同一单株中能够明显的增强抗性并且拓宽抗谱,这对培育广谱高抗的水稻来说无疑是一个很好的途径。本研究利用IRBB60（Xa-21和Xa-4）和WBB1（Xa-23）作为抗性基因供体,以宜恢1577、宜恢3551、盐恢559和明恢63等4个常用的水稻恢复系作为轮回亲本,通过3次回交和2次自交,在各个后代中分别用与三个目标基因Xa-23、Xa-21、Xa-4紧密连锁/共分离的标记RM206、pTA248、MP12在各个后代群体中进行选择并辅以接种验证,得到了抗性大幅度提高的改良后代。获得的改良后的宜恢1577、宜恢3551、盐恢559、明恢63双基因纯合累加系的抗病能力比不含任何抗性基因的对照株系大大加强,接种致病菌系P1后的病斑长度从分别从14.9cm、12.8cm、13.5cm、14.1cm下降到1.49cm、0.92cm、1.54cm、1.38cm;接种致病菌系P6后的病斑分别从14.8cm、13.2cm、13.6cm、14.8cm下降到1.47cm、1.12cm、1.33cm、1.71cm。并且对C1-C7菌系的抗性也有了极大的提高。充分显示了多种抗性基因聚合后产生的强大抗性,也为以后生产中提供抗性优良的亲本提供了可能。     

分子标记技术在绵羊育种中的应用现状分析

分子标记是以个体间核苷酸序列变异为基础的遗传标记,是DNA水平上的遗传多样性的直接反应。分子标记技术是在DNA水平上进行多态性分析的一种技术手段,具有效率高、准确度高的特点,在绵羊育种中有着广泛的应用。分子标记技术不仅可以对绵羊的基因进行定位,而且可以对绵羊群的遗传结构进行分析,重要的是可以进行绵羊的标记辅助育种,对绵羊的育种起重要作用。作者介绍了以Southern杂交、PCR扩增、重复序列和单核苷酸多态性（SNP）为基础的分子标记技术的基本原理及优缺点,重点介绍了这些分子标记技术在绵羊的体尺、屠宰、繁殖等性状中进行标记辅助选择时的应用,揭示了在实际生产中分子标记技术对于绵羊选种与选配、提高其经济价值的重要意义,并基于目前分子标记技术在绵羊育种中的运用,以及未来分子标记技术的应用作出展望。     

Molecular marker-assisted selection for yield-enhancing genes in the progeny of “9311×<Emphasis Type="Italic">O. rufipogon</Emphasis>” using SSR

Oryza rufipogon (IRGC105491) is a wild relative of cultivated rice, it contains two favorable yield-enhancing genes (yld1.1 and yld2.1) on chromosomes 1 and 2, respectively, which are capable of improving the yield of hybrid rice by 18 and 17%, respectively. SSR markers RM9, RM24, RM5 and RM306 are flanking yld1.1, while RM166 and RM208 are mapped in the close region to yld2.1. These molecular markers tightly linked to the two yield-enhancing genes were used to screen the plants of backcross population between 9311 (one of the top-performing parental lines in super hybrid rice seed production in China) and O. rufipogon. The results were as follows: (1) in BC₂F₁ population, the percentage of the individuals which contain both of the O. rufipogon alleles at marker loci RM166 and RM9 was 16.8%; (2) 1.5% individuals of total BC₃F₁ population have all the six linked markers (RM166, RM9, RM5, RM208, RM24, RM306); (3) in BC₄F₁ population, the percentage of the individuals which contain both of the two O. rufipogon alleles at marker loci RM166 and RM9 was 18.0%. Based on marker genotypes, the individuals, that contain multiple O. rufipogon markers, were selected and used for further backcross and self cross. Many 9311-type lines with yield-enhancing genes and high yield potential were obtained. After three times self-crossing a stable improved 9311 line was obtained. The results indicated that these molecular markers are feasible for marker-assisted selection (MAS) to screen rice individuals with high yield potential.     

DNA标记与动物分子育种

简要介绍了ＤＮＡ分子标记的种类,特点和产生的理论机制。阐述了基于ＤＮＡ标记找且分子育种的应用策略,对各应用领域的进展进行了生产力回顾,同时指出了分子育种中尚存在的总理２。     

猪产仔性状的分子标记研究与QTLs定位

猪的产仔性状受多个主基因的控制，比微效多基因控制的性状更易于标记辅助选择（MAS）。目前常用的方法是修选基因鉴定法和遗传连锁分析，如雌激素受体基因（ESR）PvuⅡ酶切有一个有利的B等位基因（3.7kb），其纯合子BB比纯合子AA母猪多产1.5头仔猪；促卵泡生成素受体基因（FSHR）有一个有利的A等位基因（0.5kb），AA纯合子母猪的产仔数较高。另有LHR、OPN、leptin和氟烷基因等均可作为产仔性状的候选基因。与产仔数有关的一些侯选基因和微卫星标记已经定位，国内外正用于优质高产猪的培育。     

分子标记辅助选择技术在水稻育种上的应用

分子标记辅助选择技术给水稻育种提供了新的途径,与传统育种技术相结合,可大大提高育种效率,缩短育种周期。因此,加强分子标记辅助选择技术在水稻育种上的应用研究具有重要的实践意义。在此,综述了分子标记的特点与类型及分子标记辅助选择原理,着重介绍了分子标记辅助选择在水稻育种上的利用现状,主要包括在回交育种、基因聚合、数量性状改良等方面的应用进展。同时讨论了该技术存在的问题,并展望了其应用前景。     

抗白叶枯病水稻近等基因系的选育

以沈农15为轮回亲本(RP),IRBB60为Xa-21基因供体(DP),经3代回交,2代自交,在分子标记辅助选择(molecular marker assisted selection,MAS)条件下,构建了携有抗白叶枯病基因Xa-21的近等基因系。近等基因系农艺性状与沈农15相似,抗C2(河北菌株)、C5(广东菌株)等白叶枯小种。本研究所运用的分子育种程序既能消除外源遗传背景,又能使水稻品种的农艺性状得到有效改良。     

Potential of Waxy gene microsatellite and single-nucleotide polymorphisms to develop japonica varieties with desired amylose levels in rice (Oryza sativa L.)

The Waxy (Wx) gene is responsible for the synthesis of amylose, a key determinant of the cooking and processing qualities of rice. Polymorphisms of CT-microsatellite and G–T single-nucleotide polymorphism (SNP) in the Wx gene and their relationship to amylose content (Ac) were explored using 178 non-waxy rice genotypes. Nine Wx microsatellite alleles, namely (CT)10 and 11, and (CT)14–20 were identified and 11 haplotypes were recognised by different combinations of CT-microsatellite and G–T SNP. Amylose content analysed in a random set of 39 genotypes was correlated with different microsatellite alleles/haplotypes. The highest Ac levels (>30%) correlated with (CT)10 and 16, high (26–30%) with (CT)11, 15 and 20, and intermediate (21–25%) with (CT)14, in all cases with G at the G–T SNP. The CT-classes (CT)17 and 18 (mean Ac value of 21%), could be subdivided into low amylose haplotypes (16–20%) for 17T and 18T and intermediate amylose haplotypes (21–25%) for 17G and 18G. The use of haplotypes proved to discriminate between intermediate and low amylose accessions within the same microsatellite class. Analyses of a segregating population of a cross between low and high Ac parents showed that CT-microsatellite may help to classify breeding lines and identify pollen contamination. We suggest that CT-microsatellite together with G–T SNP may be used as molecular marker by breeders to develop varieties with desired amylose levels.     

测土配方施肥中信息技术的应用及发展

论述了我国信息技术在测土配方施肥中的应用及发展现状,并重点探讨了基于MAS的手机短信测土配方施肥专家系统的应用及发展前景。鉴于21世纪手机通信遍布全球的形势及其具有的方便性、灵活性和经济性,以手机短信为载体的施肥专家系统可在农业生产中起到至关重要的作用,应用前景广阔。