AFLP技术及其在干果遗传育种研究中的应用

AFLP(扩增片段长度多态性)是检测DNA多态性的一种高效的分子标记技术,该技术的运用不需要预知基因组的序列特征,可适用于任何来源和各种复杂度的DNA,兼具RFLP技术的可靠性和RAPD技术的方便性.近年来,AFLP技术已在干果遗传育种研究中得到广泛应用.该文对AFLP技术的基本原理和反应程序进行了介绍,综述了其在干果种质资源研究、遗传图谱构建、基因标记、分子辅助选择、基因表达等方面的应用,并对AFLP技术存在的问题及其在干果遗传育种研究上的应用前景进行了探讨.     

空间诱变柱花草品系比较试验

利用空间辐射技术选育柱花草新品种(系).空间辐射柱花草种子使其后代发生突变,经连续4a接种鉴定,选育出85个株系进行试验研究.结果表明,85个株系中30个株系的牧草产量、旱季干物质产量、抗病性、长势和植株存活率表现优良,其中2001-71,2001-2,2001-80,2001-84,2001-81,2001-24以及2001-73的综合测度值极显著高于其群体,有可能成为取代其亲本热研2号柱花草而在生产上推广利用的新品系.     

Association analysis reveals effects of wheat glutenin alleles and rye translocations on dough-mixing properties

The glutenin loci of wheat (Triticum aestivum L.) are important determinants of bread-making quality, although the effects of alleles at those loci are incompletely understood. We applied an association analysis method to assess the effects of glutenin alleles and 1RS wheat–rye (Secale cereale L.) translocations on dough-mixing properties in 96 wheat cultivars and advanced lines grown at three Colorado locations while accounting for population structure and relatedness of individuals in the population. The results indicated that (1) in the majority of cases, controlling relatedness of individuals reduced the significance of associations between glutenin loci and Mixograph traits; (2) the Glu-D1 and Glu-B3 loci and 1RS translocations had greater impacts on dough-mixing properties compared to other glutenin loci; (3) Glu-B1w, Glu-D1d, and Glu-B3b were consistently associated with greater (more favorable) Mixograph peak time (MPT) than other alleles at the respective loci, whereas Glu-B1e, Glu-D1a, and Glu-B3c were associated with reduced MPT; (4) the 1BL.1RS translocation was associated with a decrease in Mixograph properties. Our results indicate that taking multiple-level relatedness of individuals into account can improve the results of association analysis for wheat-quality traits.     

6种臂形草属牧草品种比较试验

对Mulato臂形草、Mulato2号臂形草、热研3号俯仰臂形草、热研6号珊状臂形草、湿生臂形草、Abundance珊状臂形草6种臂形草属牧草进行品种比较试验。通过3a的观察测定,结果表明,6种臂形草均能适应试验区气候条件,热研6号臂形草和Mulato臂形草表现最优,产量分别达到33318kg／hm^2和32483kg／hm^2,营养期粗蛋白含量分别达到12．64％和11．77％。     

温度预处理对二倍体马铃薯花药培养诱导愈伤的影响

以原始二倍体栽培种Solanumphureja-S.stenotomum(PHU-STN)杂种无性系BD10-7和BD29-1的花药为试验材料,研究温度预处理对二倍体马铃薯花药培养过程愈伤组织诱导阶段的影响。预处理采用4℃低温、35℃热激分别进行暗培养24h、48h、72h,预处理后在22℃条件下进行花药培养,以愈伤组织的诱导率为指标探求最佳的预处理方法和水平。结果表明:4℃低温预处理48h后接种花药可明显提高愈伤组织诱导率;两个材料接种后进行热激处理愈伤组织诱导率表现不一致。     

Quantitative resistance to Botrytis cinerea from Solanum neorickii

Tomato (Solanum lycopersicum) is susceptible to gray mold (Botrytis cinerea). Quantitative resistance to B. cinerea was previously identified in a wild relative, S. neorickii G1.1601. The 122 F₃ families derived from a cross between the susceptible S. lycopersicum cv. Moneymaker and the partially resistant S. neorickii G1.1601 were tested for susceptibility to B. cinerea using a stem bioassay. Three putative quantitative trait loci (pQTL) were detected: pQTL3 and pQTL9 reducing lesion growth (LG) and pQTL4 reducing disease incidence (DI). For each pQTL, a putative homologous locus was identified recently in another wild tomato relative, S. habrochaites LYC4. pQTL3 was confirmed by assessing disease resistance in BC₃S₁ and BC₃S₂ progenies of S. neorickii G1.1601. pQTL4 was not statistically confirmed but the presence of the S. neorickii resistance allele reduced DI in all three tested populations. The reduction in LG of pQTL9 was not confirmed but rather, this locus conferred a reduced DI, similar to observations in the QTL study using S. habrochaites. The results are discussed in relation to other disease resistance loci identified in studies with other wild tomato relatives.     

Map- vs. homology-based cloning for the recessive gene ol-2 conferring resistance to tomato powdery mildew

The recessive gene ol-2 confers papilla-associated and race-non-specific resistance to tomato powdery mildew caused by Oidium neolycopersici. In order to facilitate marker assisted selection (MAS) in practical breeding programmes, we identified two simple sequence repeat (SSR) markers and one cleaved amplified polymorphic sequence (CAPS) marker which are linked to the resistance locus and co-dominantly inherited. Aiming to provide a base for ol-2 positional cloning, we used a large segregating F₂ population to merge these markers with all the ol-2 linked amplified fragment length polymorphism (AFLP^®) markers previously identified in an integrated genetic map. By screening a tomato bacterial artificial chromosome (BAC) library, we detected two BAC clones containing two expressed sequence tags (ESTs) homologous to the gene mlo, responsible for powdery mildew resistance in barley, as well as an ol-2-linked marker. Chromosomal mapping by Fluorescence in situ Hybridization (FISH) revealed major signals of the two BAC DNAs in the pericentromeric heterochromatin of the short arm of chromosome 4, in the same region where the ol-2 gene was previously mapped. The genetic and cytogenetic co-localisation between ol-2 and tomato mlo-homologue(s), in addition to the similarity of ol-2 and mlo resistances for both genetic and phytopathological characteristics, suggests that ol-2 is likely a mlo-homologue. Thus, a homology-based cloning approach could be more suitable than positional cloning for ol-2 isolation.     

受损复叶槭中酯氧合酶的生化特征及其活性变化

对被机械损伤或天牛咬食后,复叶槭叶片中酯氧合酶的生化特征及其活性变化进行了研究。结果表明:在不同温度和pH值条件下,受损植株中酯氧合酶的活性均高于对照,并且酯氧合酶的最适温度为25℃,最适pH值为7.0。在植株受损后的72h内,酯氧合酶米氏常数最低,活性最高。这表明,复叶槭通过激活酯氧合酶途径,对不同形式的损伤作出了反应。     

基于灰度共生矩阵的木材表面缺陷图像的纹理分割方法

针对木材缺陷这一自然纹理型事物,提出了一种基于灰度共生矩阵并结合模糊C均值聚类算法的纹理分割方法.对比了该方法与基于灰度-梯度共生矩阵二维阈值分割算法的分割结果,实验表明:对于木材表面缺陷这类自然纹理图像的分割,纹理分割是行之有效的方法.     

运行条件对膜污染影响及数学建模

采用膜生物反应器(MBR)对高浓度中药废水两相厌氧消化系统出水进行处理,研究了不同温度和压力条件下污泥浓度(MLSS)对MBR中膜通量衰减的影响,并在此基础上建立了不同操作条件下的膜通量随MLSS变化的数学模型。实验结果表明:MBR中膜通量不仅仅与MLSS有关,还与MBR中其他条件有关。在不同运行条件下,随着温度和操作压力的变化,膜通量随污泥浓度的增加而递减,且膜通量在一定MLSS条件下与温度和操作压力存在着正相关性。为描述这种变化趋势,进行相关性分析并建立了在3个不同温度和操作压力的条件下,膜通量和MLSS的数学模拟关系。通过建立的模型发现膜通量无论是在不同温度、还是在不同压力的条件下均与MLSS呈负相关,呈现相同的规律性即MLSS越高,膜通量越低。同时也证明温度和操作压力的增加有利于膜通量的增加。