EST-SSR标记在冬小麦品种DUS测试中的应用

为研究EST-SSR标记在应用于冬小麦品种DUS测试中的可行性,本研究利用21对小麦EST-SSR引物对45份黄淮海地区新育成冬小麦品种的遗传多样性进行了分析。在23份新育成品种中,共检测到61个位点,每个位点的等位基因数量为2~8个,平均2.90个;基因遗传多样性指数为0.08~0.79,平均为0.38。23份新育成品种的遗传距离为0.12~0.69,平均为0.40。在23份亲本品种中,共检测到63个位点,每个位点的等位基因数量为2~7个,平均3.00个;基因遗传多样性指数为0.08~0.79,平均为0.43;23份亲本品种的的遗传距离为0.09~0.81,平均为0.46。新育成品种遗传变异水平低于其亲本品种。聚类分析表明,45份品种可分为6个类群,部分申请品种和近似品种聚在一起,但其他申请品种和近似品种并未聚在一起,其中有些甚至距离较远。据此认为,EST-SSR标记用于DUS测试中近似品种的选择是可行的。     

小麦穗部组织 EST-SSR标记引物开发及其在小麦遗传多样性分析中的应用

为了筛选光温敏雄性不育系（PTGMS）小麦穗部的EST-SSR 分子标记,探讨其EST-SSR标记用于小麦品种遗传差异研究的可行性,用SSRSCAN软件对PTGMS小麦穗部的3 264条EST序列进行SSR 位点查找,结果得到108条含有SSR标记的序列。设计64对引物并进行PCR扩增及非变性聚丙烯酰胺凝胶(PAGE)电泳。结果显示,64对引物中有41对能在42个小麦品种中扩出PCR条带,有多态性条带的为36对,具有较高的扩增效率。聚类分析结果显示,42个小麦品种的遗传相似系数在0.64~0.87之间,3个PTGMS小麦品种具有较高的遗传相似系数。     

62个小麦品种基于EST-SSR标记的遗传多样性分析

为了解从匈牙利、捷克引进的39个欧洲小麦品种的遗传多样性,以23个中国黄淮冬麦区小麦品种为对照,利用55个多态性EST-SSR标记检测参试材料的遗传多态性.结果表明,55个标记在62 个小麦品种中检测到213条差异带,能够将所有品种区分开来;单个引物扩增差异带数目为1～9条,平均为3.87条;多态性信息指数(PIC)为0～0.87,平均为0.53;品种间遗传相似系数为0.48～0.94,平均为0.70.引进品种平均等位变异数高于国内品种,而相似系数却低于国内品种,表明引进品种遗传变异基础大于本研究中的国内品种.聚类分析在相似系数0.69处将62个品种聚为两类,第I类包含匈牙利的2个品种,其他60个品种聚为第II类.第II类又分为四个亚类,其中,第一(II-1)和第三亚类(II-3)包含了引进和国内品种,而第二亚类(II-2)全部为国内品种,第四亚类(II-4)全部为引进的品种.     

基于EST-SSR标记的黄淮海和南方大豆育成品种遗传多样性研究

以我国黄淮海和南方大豆产区的153份大豆育成品种为材料,选用26对EST-SSR分子标记通过Power Marker V 3.25等软件对其进行遗传多样性、相似性与特异性分析。结果表明:153份大豆共检测到238个等位变异,变幅3~25个,平均8.1个;多态信息量变幅0.15~0.87,平均0.61;遗传变异丰富。基于EST-SSR分子标记的聚类分析将153个材料聚为3大类13小类。特异性分析表明,黄淮海产区的育成品种的特有等位变异较南方产区的多,特缺等位变异要少于南方,1991-2000年的特有等位变异最多;随着时间的推移,大量的外来育种材料应用于大豆育种,大豆育成品种的遗传基础有所拓宽。EST-SSR标记适用于大豆育成品种遗传多样性研究,研究结果可以为以后大豆种质资源保存与新品种的选育提供分子水平上的理论支持。     

利用ISSR和EST-SSR标记分析茶树遗传多样性的比较

为了比较EST-SSR和ISSR 2种标记在茶树遗传多样性分析上的适用性,应用这2种技术分析了33份茶树资源的遗传多样性.12个ISSR引物共扩增出248条谱带,多态性比率为91.94%,平均多态信息量(PIC)为0.318.30对EST-SSR引物每个位点平均等位基因数为4.9个,平均多态信息量(PIC)为0.499.2种标记都能揭示茶树资源较高的遗传多样性,但从信息量上比较,ISSR标记比EST-SSR标记有较高的分析效率.ISSR和EST-SSR揭示的茶树遗传相似系数分别为0.709和0.734,二者接近.聚类分析表明二者有一定差异,遗传相似系数矩阵相关性分析结果表明2种标记间存在一定的正相关性(r=0.817,P<0.01).因此,这2种标记均可适用于茶树遗传多样性分析.     

EST SSR标记在冬小麦品种DUS测试中的应用

为研究ESTSSR 标记在应用于冬小麦品种DUS测试中的可行性,本研究利用21对小麦ESTSSR引物对45份黄淮海地区新育成冬小麦品种的遗传多样性进行了分析。在23份新育成品种中,共检测到61个位点,每个位点的等位基因数量为2~8个,平均2.90个;基因遗传多样性指数为0.08~0.79,平均为0.38。23份新育成品种的遗传距离为0.12~0.69, 平均为0.40。在23份亲本品种中,共检测到63个位点,每个位点的等位基因数量为2~7个,平均3.00个;基因遗传多样性指数为0.08~0.79,平均为0.43;23份亲本品种的的遗传距离为0.09~0.81, 平均为0.46。新育成品种遗传变异水平低于其亲本品种。聚类分析表明,45份品种可分为6个类群,部分申请品种和近似品种聚在一起,但其他申请品种和近似品种并未聚在一起,其中有些甚至距离较远。据此认为,ESTSSR标记用于DUS测试中近似品种的选择是可行的。     

木薯种质库遗传多样性的EST-SSR标记

采用49对表达序列标签-微卫星标记(EST-SSR)引物对76份木薯材料(39份新引进材料和37份原始材料)进行遗传多样性分析,共获得135个多态性位点,每对引物检测等位基因数为1～4个,平均为2.75个;扩增产物的片段大小范围在250～750 bp之间.根据遗传相似系数的聚类分析将所有材料分为5组,即A、B、C、D和E组,其中A、C、D、E 4个组均为新引进种质,B组以0.625 0为阈值,又将其分为5个亚组,其中B1、B2除了个别外,均为新引进种质,B2来自非洲,而B3、B4和B5主要为原有种质和育种品系.同时估算了分组后组间的遗传多样性指数,发现其平均遗传多样性指数达到0.446 5.比较原来多样性分析结果,说明新引进这一批国外种质具有新的遗传类型,丰富了我国木薯种质资源库.     

利用EST-SSR标记研究适制绿茶与乌龙茶品种的遗传多样性与遗传结构

基于26个EST-SSR标记研究了31份适制绿茶和37份适制乌龙茶品种的遗传多样性差异,结果表明两类品种在23个EST-SSR位点上的等位变异数目相等,另3个位点各存在一个等位位点的差异。乌龙茶品种遗传多样性指数（H）、多态性信息含量（PIC）和平均遗传距离(GD)均略高于绿茶品种。基于数学模型的聚类分析将供试品种分为两个亚类群,亚群A中67.9%的品种为乌龙茶适制品种;亚群B中71.0%的供试绿茶品种聚类其中。基于Nei’s遗传距离的聚类分析将供试品种分为3个类群,其中类群Ⅰ和Ⅱ中以乌龙茶品种为主,分别占聚类品种数的69.6%和66.7%;而类群Ⅲ中61.3%的供试绿茶品种聚类其中。多数品种按适制类型聚类,说明绿茶和乌龙茶品种间的遗传结构存在差异。但也有部分品种在不同的群体结构中呈穿插分布,推测与其适制类型划分的恰当性、地理来源和遗传背景有关。     

利用EST-SSR标记研究黄金茶群体遗传多样性及遗传分化

利用19对茶树EST-SSR引物对黄金茶群体的38个单株进行了遗传多样性和亲缘关系分析。19对引物共检测到等位位点37个,每个引物1~3个,平均1.95个;期望杂合度(He)在0.03~0.65之间,平均值0.32;观测杂合度(Ho)在0~0.97之间,平均值0.33;群体内的Shannon指数0.55。以上结果均说明黄金茶群体的遗传多样性较低。基于EST-SSR数据以SAHN邻接法对供试种质资源进行UPGMA遗传相似性聚类,并绘制树状聚类图,按相似系数0.77可将参试的38份种质资源分为六大类。根据不同单株间的相似系数可为黄金茶群体的遗传改良提供一定参考。同时,AMOVA分析表明,黄金茶群体的遗传变异21.77%发生在种群间,78.23%发生于单株间,不同区域的种群间基因流为1.80,这可以为黄金茶群体的保护提供一定理论依据。     

利用EST-SSR分析江北茶区茶树资源的遗传多样性和遗传结构

利用25对EST-SSR引物对江北茶区的45份茶树初级核心种质的遗传多样性、遗传结构和亲缘关系进行了分析。25对引物共检测到83个等位位点,平均每对引物可检测到等位位点3.3个,可鉴定的基因型为6个。引物的PIC值平均为0.61,扩增位点的观测杂合度高于期望杂合度。45份供试种质中可观测的等位位点平均为4.2个,有效等位位点为2.8个。等位位点观测杂合度平均为0.73,基因多样性指数为0.61,Shannon信息指数为1.11。江北茶区主要省份间茶树种质的遗传分化程度较低(Gst=0.2),而基因流(Nm=3.9)较高。AMOVA分析显示,95.97%的变异发生于居群内。45份供试种质间的遗传相似系数在0.32~0.89之间,聚类分析表明供试资源在亲缘关系上未表现出明显的地区分化。湖北、安徽和陕西三个主要省份茶树种质间的遗传距离平均为0.048,其中陕西资源在亲缘关系上略远于湖北和安徽。     

Detection of powdery mildew in two winter wheat cultivars using canopy hyperspectral reflectance

To determine the most sensitive spectral parameters for powdery mildew detection, hyperspectral canopy reflectance spectra of two winter wheat cultivars with different susceptibilities to powdery mildew were measured at Feekes growth stage (GS) 10, 10.5, 10.5.3, 10.5.4 and 11.1 in 2007–2008 and 2008–2009 seasons. As disease indexes increased, reflectance decreased significantly in near infrared (NIR) regions and it was significantly correlated with disease index at GS 10.5.3, 10.5.4 and 11.1 for both cultivars in both seasons. For the two cultivars, red edge slope (dr_red), the area of the red edge peak (Σdr_{680−760 nm}), difference vegetation index (DVI) and soil adjusted vegetation index (SAVI) were significantly negatively correlated with disease index at GS 10.5.3, 10.5.4 and 11.1 in both seasons. Compared with other parameters, Σdr_{680−760 nm} was the most sensitive parameter for powdery mildew detection. The regression models based on Σdr_{680−760 nm} were constructed at GS 10.5.3, 10.5.4 and 11.1 in both seasons. These results indicated that canopy hyperspectral reflectance can be used in wheat powdery mildew detection in the absence of other stresses resulting in unhealthy symptoms. Therefore, disease management strategies can be applied when it is necessary based on canopy hyperspectral reflectance data.     

国内胡麻育成品种的遗传多样性分析

胡麻是我国主要的油料作物,在区域经济发展中起着重要作用。胡麻的遗传多样性分析工作对胡麻种质资源的收集、保存、分类、鉴定以及育种都是非常必要的。本试验对目前国内不同时期选育的96份胡麻品种进行形态学标记和SRAP分子标记分析以评价其种质间的遗传多样性。通过比较形态学标记和SRAP分子标记的聚类图,都得到了预期的试验结果,两者都可以用于胡麻遗传多样性和亲缘关系的分析。对于国内胡麻育成品种之间的划分总体一致,但在具体类别中却存在着一定程度上的偏差,可能是因为SRAP标记在DNA水平上反映了更多的的差异,而形态标记的基因型与SRAP标记检测出的位点相关性很小。     

Economic returns from fungicide application to control foliar fungal diseases in winter wheat

Fungicides are commonly applied to control foliar fungal diseases of winter wheat in the central Great Plains of the United States and often are routinely recommended. However, economic benefits from fungicide application in winter wheat have rarely been quantified in this region. A total of eight field experiments were conducted in 2006 and 2007 in Nebraska, USA to quantify yield increases from fungicide applications to control foliar fungal diseases in winter wheat. Experiments were conducted at the same four locations (Mead, Clay Center, North Platte and Sidney) in both years. The fungicides used were azoxystrobin + propiconazole, pyraclostrobin, propiconazole, azoxystrobin and trifloxystrobin + propiconazole applied at varying rates and growth stages. Average wheat prices were calculated from data provided by the United States Department of Agriculture (USDA) Agricultural Marketing Service. Average fungicide and fungicide application costs were obtained through surveys of local retailers, chemical manufacturers and commercial applicators. These prices and costs were used to calculate net returns from fungicide treatments. The probability of a positive net return was 0.60, 1.00 and 0.80 in 2006 (dry, low disease severity), 2007 (wet, moderate to high disease severity) and both years combined, respectively. Net returns ranged from $−101 ha⁻¹ to $172 ha⁻¹ in 2006 and from $60 ha⁻¹ to $294 ha⁻¹ in 2007. Net returns were at least two times the total cost ($2 return on $1 investment) in 4 out of 60 or 6.7% of treatments in 2006 and 51 out of 60 or 85% of treatments in 2007. In 2006, the best net returns occurred at Mead and Clay Center and resulted from the treatments 1) azoxystrobin + propiconazole applied at Zadoks growth stage (GS) 31 (first node detectable) at a rate of 0.58 l ha⁻¹ and 2) azoxystrobin + propiconazole applied at GS 31 at a rate of 0.58 l ha⁻¹ and again at GS 37 (flag leaf just visible) at the same rate. In 2007, the treatments that resulted in the best net returns were 1) azoxystrobin + propiconazole applied at GS 39 (ligule/collar of flag leaf just visible) at a rate of 1.02 l ha⁻¹, 2) pyraclostrobin applied at GS 39 at a rate of 0.66 l ha⁻¹, 3) propiconazole applied at GS 39 at a rate of 0.29 l ha⁻¹, and 4) trifloxystrobin + propiconazole applied at GS 39 at a rate of 0.73 l ha⁻¹. For the same fungicide applied at the same rate at GS 31 and GS 39 in 2007 (wet, moderate to high disease severity), the GS 39 application generally resulted in a higher net return than the GS 31 application. Averaged across treatments and locations, net returns were $6 ha⁻¹ and $183 ha⁻¹ in 2006 and 2007, respectively. The results from this study indicate that foliar fungicide application to winter wheat can be profitable in years with moderate to high disease severity; however, net loss can result if fungicides are applied in years with low disease severity.     

Identification of new puroindoline genotypes and their relationship to flour texture among wheat cultivars

Puroindoline genotypes (Pina and Pinb) and their encoded proteins related to grain hardness were studied in various common wheat cultivars from Australia, China, Japan, Korea and North America. Most of the hard wheats had the Pinb-D1b genotype with a glycine to serine mutation at position 46. In addition to the known Pina and Pinb genotypes, cultivars were found with Pina and Pinb double-null mutations (Pina-D1b/Pinb-D1h (t)) and a new Pinb frameshift mutation (designated Pinb-D1i (t)) within the region encoding a tryptophan-rich domain. This new Pinb frameshift mutation was found only in Chinese cultivars. Endosperm proteins encoded by Pina and Pinb in these cultivars were analysed by 2D-gel electrophoresis (IPG×SDS-PAGE). Cultivars with Pina and Pinb double-null mutations showed no PIN-a or PIN-b protein, and cultivars with Pinb-D1i (t) had no PIN-b protein. Surprisingly, cultivars with Pinb-D1b had severely reduced amounts of PIN-b and cultivars with Pinb-D1c showed no PIN-b proteins. Grain hardness among cultivars having mutated Pinb may be explained by the amount of PIN-b protein and not by the type of amino acid substitutions.     

Effect of nitrogen application rate on content of glutenin macropolymer and high molecular weight glutenin subunits in grains of two winter wheat cultivars

Two winter wheat (Triticum aestivum L.) cultivars differing in grain protein content were selected to study the effect of N application rate on changes in contents of glutenin macropolymer (GMP) and high molecular weight glutenin subunits (HMW-GS) during grain filling. Contents of GMP and HMW-GS were much higher in the high GPC cultivar, Xuzhou 26, than those in low GPC cultivar, Ningmai 9. N increased contents of GMP and HMW-GS in Xuzhou 26 with N rate between 0 and 300 kg ha⁻¹, while at the very high N rate of 300 kg ha⁻¹ the contents of GMP and HMW-GS in Ningmai 9 decreased. The high contents of GMP and HMW-GS at maturity were closely related to the rapid increase in contents of GMP and HMW-GS during the initial period of their synthesis. HMW-GS and GMP content were closely correlated. The total HMW-GS content was important in determining GMP content than the content of any HMW-GS pair or any individual HMW-GS present in the selected cultivars. The pattern of response of GMP content to N application rate was closely related to the regulatory effect of N on HMW-GS synthesis.     

国家冬油菜区试新品种ＳＳＲ指纹图谱构建与遗传关系分析

采用从２００对ＳＳＲ引物筛选中获得的１８对多态性好、带纹清晰的引物,对２００５～２００６年度国家区试 １０２份冬油菜新品种ＰＣＲ扩增,获得８８条谱带,平均每对引物４．９条,多态性比率平均达到８６．３６％,ＰＩＣ平均值为 ０．６４,构建了该年度国家区试１０２份冬油菜新品种ＤＮＡ指纹图谱。聚类分析表明,所有参试品种在相似系数０．７２５ 处被划分为Ａ、Ｂ、Ｃ、Ｄ、Ｅ、Ｆ、Ｇ７个簇。其中Ａ簇包括８１份品种,其他２１份参试品种分布在余下的６簇。聚类分 析表明,Ａ簇内华中农业大学与湖南省品种有相近亲缘关系,聚成一组;而中国农业科学院油料作物所、贵州油料 作物研究所以及陕西地区部分品种相似系数高,聚成另一组,分别拥有３７和４２份材料。聚类分析同时显示,同一 单位的育成品种遗传背景相近。     

马山县甘蔗新品种比较试验

为筛选出适宜马山县种植的甘蔗优良品种,实现品种多样化,优化甘蔗品种结构,该研究以新台糖22号为对照,对近几年登记推广的7个甘蔗新品种进行一年新植一年宿根的比较试验,调查其主要农艺性状、经济性状和抗性等指标,并进行对比分析和综合评价.试验结果表明,桂糖49号、桂糖44号和桂糖42号这3个品种的农艺性状、经济性状、抗性等综...     

Responses of glutamine synthetase activity and gene expression to nitrogen levels in winter wheat cultivars with different grain protein content

Glutamine synthetase (GS) plays a central role in plant nitrogen (N) metabolism, which improves crops grain protein content. A pot experiment in field condition was carried out to evaluate GS expression and activity, and grain protein content in high (Wanmai16) and low grain protein (Loumai24) wheat cultivars under two N levels (0.05 and 0.15 g N kg⁻¹ soil). High nitrogen (HN) resulted in significant increases in GS1 and GS2 expression at 10 days after anthesis (DAA), and higher GS activity during the entire grain filling stage. HN also significantly increased yield, grain protein content and protein fraction (except for glutenin of Luomai24) in two wheat cultivars, which indicated that it increased grain yield and protein content by improving nitrogen metabolism. Wanmai16 showed higher grain protein content, gliadin and glutenin content, and had higher expression level of GS2 both in flag leaves and grains at early grain filling stage. However, Luomai24 had greater yield and higher expression level of GS1. The difference expression of GS2 and GS1 genes indicates they had various contributions to the accumulation of protein and starch in wheat grains, respectively. The results suggest that GS2 would be serving as a potential breeding target for improving wheat quality.     

Sheep grazing and defoliation of contrasting varieties of organically grown winter wheat with and without undersowing

Field experiments in Gloucestershire, UK, in the 1990–91, 1991–92, 1993–94 and 1994–95 growing seasons explored the merits of grazing in spring a traditional tall wheat (Triticum aestivum) variety, Maris Widgeon, with more modern shorter varieties. In the first 2 years, defoliation was achieved by mowing at 7 cm in March and/or April. In the second 2 years, varieties sown at two sowing dates were grazed by sheep at a stocking rate of 42 × 50 kg sheep ha^?1 for 3 or 4 days in March. Defoliation reduced crop height and interception of photosynthetically active radiation (PAR). In 1991–92, mowing significantly reduced grain yield of some of the shorter varieties but not of Maris Widgeon. This interaction was related to the amount of PAR intercepted. In this year, mowing improved the establishment of undersown white clover (Trifolium repens) and perennial ryegrass (Lolium perenne), but in subsequent years the conditions were much drier and undersowing failed. In the last two experiments, grazing in March did not significantly reduce grain yield of any variety. The quality of the forage eaten by the sheep had a modified acid-detergent fibre (MADF) content of less than 300 g kg^?1 dry matter (DM) and a crude protein (CP) content of more than 200 g kg^?1 DM in both seasons. Yield of DM and calculated metabolizable energy (ME) of different varieties removed by the sheep interacted strongly with sowing date. September-sown Maris Widgeon provided ≈ 0·7 and 0·3 t DM ha^?1 (or 7·8 and 3·4 GJ ME ha^?1) in March 1994 and March 1995 respectively. However, the shorter wheat varieties, Hereward and Genesis, only provided 0·3 and 0·1 t DM ha^?1 when sown at the same time in the 2 years. At later sowing dates all of the varieties only provided about 0·1 t DM ha^?1 when sown in October 1993, or 0·01 t DM ha^?1 when sown in November 1994. Sheep grazing reduced total weed biomass in June, and reduced the emergence of weed seedlings from soil samples collected after the wheat harvest. Effects of defoliation on foliar infection by Septoria tritici were inconsistent.