十字花科栽培蔬菜及野生近缘种资源对小菜蛾的抗性分析

小菜蛾是危害十字花科蔬菜最严重的害虫,造成蔬菜产业巨大经济损失。现有育种材料中抗小菜蛾的资源非常稀缺,制约了抗虫新品种的选育。本研究利用国家蔬菜种质资源中期库中近年收集的来自10个国家,42个种,218份十字花科栽培蔬菜及野生近缘种资源进行了小菜蛾抗性鉴定。这些资源的抗性水平从极抗到极感皆有分布,除极端抗/感材料较少外,总体上呈均匀分布。属间、种间、变种间的平均抗性差异显著。同种植物的不同种质间抗性分布亦广。栽培资源比野生资源具有相对更高的平均抗虫水平,但是后者高抗材料更多。北部欧洲等地是抗性资源分布相对集中的地理区域。本研究获得抗虫资源19份,其中高抗资源4份,这些材料对蔬菜抗虫育种和抗虫基因发掘具有重要应用价值。     

小白菜种质资源对小菜蛾的抗性评价

本文就小白菜种质资源对小菜蛾的抗性进行室内鉴定,结果表明268份材料的虫害指数分布在18.10～100.00之间,种质资源间抗虫性差异达到显著水平.聚类分析将268份种质资源分为6大类,与高抗、抗、中抗、中感、感、高感相对应,其中筛选出高抗和抗性材料分别为6和11份.对268份材料的主要形态性状与虫害指数和抗性级别的相关分析表明,小白菜种质资源叶面的皱缩度与抗虫性存在一定的相关性,认为从叶面平滑型的种质资源中筛选抗虫性材料的可能性更大.     

基于遗传和表型特征的海岛棉遗传多样性分析

依据海岛棉种质资源的遗传及表型特征对其遗传多样性进行研究非常重要,可为海岛棉杂交育种选配亲本、引进新的种质资源拓宽优异基因范围以及培育海岛棉新品种提供理论根据。本研究通过利用125对SSR分子标记鉴定结果和13个农艺性状2年田间表型调查结果,对94份海岛棉种质资源进行遗传多样性分析,将这些材料按照遗传和表型特征进行类群的划分和比较,结果表明:(1)通过标记分析共检测到420个位点,其中249个为多态性位点,并应用Nei-Li相似系数法对94份材料间的遗传相似系数进行评估,发现94份海岛棉资源材料的遗传相似系数在0.46~0.95之间浮动,同时利用SSR分子标记将94份海岛棉资源材料划分为4大类群,分类结果与系谱分析基本吻合。(2)对94份海岛棉资源材料进行13个农艺性状及品质性状2年调查分析,发现供试材料品质性状的变异范围较广,而产量性状的变异范围相对较小。其中,各品种中马克隆值的多样性指数最高,最小的是单铃重。聚类分析发现,第Ⅰ类群产量性状的平均值较高;第Ⅱ类群虽在产量性状上不占优势,但其品质性状的表现较其他组别优异;第Ⅲ类群多为低产低质品种;第Ⅳ类群品种品质较优,产量变化范围较大。(3)利用SSR标记和农艺性状分析2种方法对94份海岛棉资源材料进行分析,结果均显示出较丰富的遗传多样性;2种方法的聚类结果基本一致,聚类结果与地理分布有明显的联系。     

栽培萝卜植株地上部表型多样性分析

萝卜是我国重要的蔬菜作物,为了充分了解和有效利用国家蔬菜种质资源库栽培萝卜种质资源遗传多样性,以中期库经过初步鉴定的635份栽培萝卜种质为材料,对其植株地上部分39个表型性状进行了系统调查和分析。结果表明:(1)在19个质量性状中,下胚轴颜色的Shannon-Weiner多样性指数最高,为1.72,长角果着生姿势最低,为0.47,平均多样性指数为1.11。(2)20个数量性状的变异系数分布范围是13.33%~93.97%,平均变异系数为37.96%,其中小裂片间距的变异系数最大,花萼长度的变异系数最小;这20个数量性状的Shannon-Weiner多样性指数的变化范围为1.20~2.15,多样性指数平均值是1.94;其中花瓣宽和千粒重的多样性指数最高(2.15),其次分别是花瓣开展度(2.14)、子叶长(2.13)、花瓣长(2.13)、花萼长(2.12)和子叶凹槽深(2.11);基生叶叶片宽度的多样性指数最低(1.20)。(3)采用SAS 9.2对参试材料20个数量性状的主成分分析结果表明,7个主成分因子的累计贡献率达72.87%。(4)根据非加权组平均法(UPGMA),将供试材料分为5大类群,其中第Ⅰ类群包含1份种质,该种质为德国引进,角果长度最长为204.70 mm,角果喙长最长为122.90 mm,且长角果颜色为紫色;第Ⅱ类群包含4份种质,角果平均长度、喙长、平均单角果粒数、花瓣平均长度、花瓣平均宽度和花瓣开展度6个数量性状数值在5个类群中最小;第Ⅲ类群包含1份种质,其子叶宽度、子叶叶柄长度、花瓣长度、花瓣宽度、花萼长度、花瓣开展度在5个类群中均最大,且叶脉色和叶柄色均为紫色;第Ⅳ类群包含428份材料,其又可分为两个亚群,第Ⅳ-1亚群包含50份材料,主要是长荚萝卜和油萝卜,第Ⅳ-2亚群包含378份材料,花叶类型占98.94%;第Ⅴ类群包含201份材料,全部为板叶类型材料。研究结果为辨识和利用栽培萝卜种质资源提供了有效信息。     

湖南地区新收集烟草种质资源的鉴定与遗传多样性分析

"第三次全国农作物种质资源普查与收集行动"湖南项目组经过系统调查共收集到烟草种质资源32份。本研究从收集到的烟草种质资源中筛选出23份特色种质材料,对其22个农艺性状进行鉴定和遗传多样性分析,结果表明供试种质材料遗传多样性丰富,其中数量性状的多样性指数普遍较高,多样性指数最高的3个数量性状分别是节距、叶数和叶宽,质量性状以叶形的多样性指数最高;性状变异系数最大的是叶柄,其次是株高和叶宽。对新收集烟草种质资源进行聚类分析,可以将其分为3个类群,其中第Ⅱ类群的种质叶片数多,第Ⅲ类群的植株较高,可用于高产育种实践或作为中间材料使用。对特色烟草种质进行主要病害的抗性鉴定,发现13份种质材料对黑胫病、TMV或CMV表现出抗性,其中2份种质兼抗黑胫病和TMV,可用于抗病育种。由此可见,开展烟草种质资源的普查收集工作意义重大,可以为新品种的选育提供更丰富的亲本材料或中间材料。     

240份玉米自交系纹枯病抗性鉴定与评价

在人工接种条件下,连续3年对240份玉米自交系纹枯病抗性进行鉴定和评价,分析了玉米纹枯病抗性与主要农艺性状的相关性。结果表明,玉米纹枯病抗性资源较为缺乏,240份自交系中无免疫或高抗的材料,有中抗自交系4份、感病自交系18份、高感自交系218份。旅大红骨、Reid、PA和塘四平头类群自交系中未发现玉米纹枯病抗源,PB类群和Lancaster类群自交系纹枯病抗性相对较好,今后应主要从这两类种质中寻找玉米纹枯病抗源。玉米纹枯病病情指数与株高、穗位高、穗位高/株高、穗下节间数和穗下平均节间长均呈极显著负相关,这些表型可以作为非接种条件下筛选抗玉米纹枯病种质的参考指标。     

橡胶草及其同域近缘种表型多样性研究

对蒲公英属橡胶草及其同域10个近缘种共13份材料的59个表型性状(数量性状24个,质量性状35个)进行了观测,通过方差分析、因子分析和聚类分析对其形态性状多样性和种间亲缘关系进行研究,以明确各表型性状对种质分类的重要性及其贡献,为橡胶草品种选育及蒲公英属植物的分类和种质资源保存利用提供依据。结果显示:(1)13份蒲公英属种质资源在数量性状上变异系数在7.50%~55.00%之间,平均为28.25%,多样性指数在1.157~2.032之间,平均为1.663,具有丰富的表型多样性。(2)质量性状方面,变异系数的变化范围在20.40%~67.44%之间,多样性指数变化范围在0.271~1.672之间,平均为1.136,总体上是数量性状形态多样性指数大于质量性状。(3)59个性状的主成分分析中前7个主成分的累计贡献率为84.767%,花部形态变异是蒲公英属植物表型分化的主要因素。(4)利用欧氏距离进行的Ward’s聚类分析结果表明,13份材料可分为4大类群,同一地区的大部分种聚在一起,呈现出一定的地域性,亲缘关系较近;但来源于3个居群的橡胶草却被划分在2个类群中,表现出较远的亲缘关系。研究表明,蒲公英属植物种质材料具有丰富的质量和数量性状变异,表型多样性丰富。     

重庆绿豆新收集种质资源的遗传多样性分析及抗枯萎病鉴定

"第三次全国农作物种质资源调查与收集"项目组历时2年从重庆地区收集到49份绿豆种质资源,供发掘优异基因及育种利用,我们评估这些资源的表型遗传多样性和枯萎病抗性水平。结果表明:这些新收集绿豆种质资源遗传多样性丰富,数量性状遗传多样性指数排序为:单株荚数株高主茎节数分枝数底荚高度荚宽荚长百粒重开花期单荚粒数成熟期出苗期;各质量性状遗传多样性指数排序为:荚形分枝性复叶叶形粒形种皮光泽度生长习性、结荚习性熟荚色对生单叶形花色、主茎茸毛色子叶色粒色幼茎色。聚类分析将49份种质资源划分为5个类群,第Ⅰ类群主要表现为矮秆、宜机收,第Ⅱ类群主要是大籽粒材料,第Ⅲ类群可作黄籽粒特色材料加以利用。三维散点图中,前3个主成分将49份种质资源大致分布在2个区域,分布在区域Ⅰ的材料多为直立型材料,而分布在区域Ⅱ的材料多为半蔓生型材料。经枯萎病抗性鉴定,从49份种质资源中筛选出中抗资源9份,抗病资源3份,高抗资源1份。本研究为后续优良种质的开发利用和抗绿豆枯萎病基因发掘提供了理论和种质基础。     

叶用芥菜种质表型性状的遗传多样性分析

为有效利用叶用芥菜种质资源,对筛选出的24份叶用芥菜品系资源的11个表型性状,应用相关系数、聚类分析和主成分分析等多元统计方法进行遗传多样性分析。结果表明:叶用芥菜种质资源具有丰富的遗传多样性;11个表型性状平均变异系数为44.74%,叶片数的变异系数最大,为150.80%;净菜率变异系数最小,仅为9.54%。通过系统聚类,将参试的24份品系分为3个类群,第Ⅰ类群有14份材料,第Ⅱ类群有5份材料,第Ⅲ类群有5份材料,各类群性状之间的差异较明显,明确了品系类群间存在的亲缘关系。在主成分分析中,可选取方差累计贡献率为86.62%的前5个主成分来评价24份叶用芥菜品系资源。本研究揭示了叶用芥菜不同品系的表型特异性和遗传多样性,筛选出一些特异品系资源,为高产优质叶用芥菜新品种(系)的选育提供重要的科学依据。     

重庆地区新收集烟草种质资源的鉴定评价与整理编目

为将"第三次全国农作物种质资源普查与收集行动"重庆项目组收集到的63份烟草种质资源入国家种质资源库进行编目和保存,对其进行田间鉴定和拍照记录。形态特征和主要农艺性状的遗传多样性分析表明,供试种质的数量性状和质量性状遗传多样性丰富,质量性状以叶形的多样性指数最高,数量性状中叶长、叶宽和茎围的多样性指数较高。聚类分析将新收集烟草种质资源分为4个类群,其中第Ⅰ类群以黄花烟为主,第Ⅲ类群的植株最高、叶片最大,可用于高产育种。主要病毒病的抗性鉴定发现,有11份种质TMV和CMV的抗性均较强,其中2份种质对TMV免疫且高抗CMV,可用于抗病育种。另外,通过田间表型和SSR分子标记对拟编目资源进行鉴定整理,剔除了重复的种质资源。因此,烟草种质资源的普查收集工作对于丰富国家烟草种质资源库和新品种选育具有重大意义。     

Genetic diversity of sorghum accessions resistant to greenbugs as assessed with AFLP markers.

Sorghum, Sorghum bicolor (L.) Moench, is the fifth most important cereal crop grown worldwide and the fourth in the United States. Greenbug, Schizaphis graminum (Rondani), is a major insect pest of sorghum with several biotypes reported to date. Greenbug biotype I is currently the most prevalent and most virulent on sorghum plants. Breeding for resistance is an effective way to control greenbug damage. A successful breeding program relies in part upon a clear understanding of breeding materials. However, the genetic diversity and relatedness among the greenbug biotype I resistant accessions collected from different geographic origins have not been well characterized, although a rich germplasm collection is available. In this study, 26 sorghum accessions from 12 countries were evaluated for both resistance to greenbug biotype I and genetic diversity using fluorescence-labeled amplified fragment length polymorphism (AFLP). Twenty-six AFLP primer combinations produced 819 polymorphic fragments indicating a relatively high level of polymorphism among the accessions. Genetic similarity coefficients among the sorghum accessions ranged from 0.69 to 0.90. Cluster analysis indicated that there were two major groups based on polymorphic bands. This study has led to the identification of new genetic sources of sorghum with substantial genetic variation and distinct groupings of resistant accessions that have the potential for use in the development of durable greenbug resistant sorghum.     

Plant resistance and its effect on the peritrophic membrane of southwestern corn borer (Lepidoptera: Crambidae) larvae

The southwestern corn borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), is a serious pest of corn, Zea mays L., in the southern United States. Corn germplasm lines with conventional genetic leaf-feeding resistance to this pest, the fall armyworm, Spodoptera frugiperda (J.E. Smith), and other lepidopterans have been released to the public by USDA-ARS scientists located in Mississippi. Recent studies suggest the insect resistant lines disrupt the integrity of the peritrophic membrane of the fall armyworm. The objectives of this study were to investigate any morphological differences in the structure of the peritrophic membrane of southwestern corn borer larvae feeding on resistant and susceptible corn hybrids and to quantify the damage. Larvae were reared under field and laboratory conditions on three corn hybrids (two resistant and one susceptible). Scanning electron microscopy was used to examine the peritrophic membrane for abnormalities such as holes or tears and to count the holes or tears in the membrane. Differences in the degree of damage to peritrophic membrane of larvae fed on resistant and susceptible plants were not detected. Up to five distinct layers of the membrane were observed in each larva. Variation in the amounts of damage to the peritrophic membrane observed from larvae feeding on all plant material was high. Plant resistance adversely affects growth and development of southwestern corn borer larvae, and further investigations are needed to explain the role of plant resistance and its relation to peritrophic membrane in southwestern corn borer larvae.     

Variation for Resistance to <i>Alternaria tenuissima</i> and Potential Structural Mechanism among Different Cultivars of <i>Chrysanthemum morifolium</i>

Black spot disease, caused by the necrotrophic fungus Alternaria tenuissima (Fr.) Wiltsh (A. tenuissima), is considered a highly destructive disease of Chrysanthemum (Chrysanthemum morifolium Ramat.). A set of 17 accessions of commercial chrysanthemum cultivars were evaluated for resistance to A. tenuissima by seedling artificial inoculation. It was found that the reaction of the accessions to artificial inoculation ranged from resistant to highly susceptible. Five varieties of chrysanthemum (‘Zhongshan Taogui’, ‘Jinba’, ‘Zhongshan Jinguan’, ‘Jinling Wanhuang’ and ‘Jinling Yangguang’) were resistant; two varieties of chrysanthemum (‘Zhongshan Xinggui’ and ‘Zhongshan Jinkui’) were moderately resistant; and others were susceptible to various degrees, four varieties of chrysanthemum (‘Zhongshan Zihe’, ‘Zhongshan Jiuhong’, ‘Zaoyihong’ and ‘Jinling Jiaohuang’) were highly susceptible, especially. Some leaf morphological features of two resistant and two highly susceptible cultivars were further researched. Trichome density, length, height, gland size and stomata density were found to be associated with plant passive resistance. Resistant varieties that were identified in present study will be promising germplasm for exploitation of breeding programmes aimed at developing A. tenuissima-resistant cultivars and increasing genetic diversity.     

Haplotype diversity and population structure in cultivated and wild barley evaluated for Fusarium head blight responses

Fusarium head blight (FHB) is a threat to barley (Hordeum vulgare L.) production in many parts of the world. A number of barley accessions with partial resistance have been reported and used in mapping experiments to identify quantitative trait loci (QTL) associated with FHB resistance. Here, we present a set of barley germplasm that exhibits FHB resistance identified through screening a global collection of 23,255 wild (Hordeum vulgare ssp. spontaneum) and cultivated (Hordeum vulgare ssp. vulgare) accessions. Seventy-eight accessions were classified as resistant or moderately resistant. The collection of FHB resistant accessions consists of 5, 27, 46 of winter, wild and spring barley, respectively. The population structure and genetic relationships of the germplasm were investigated with 1,727 Diversity Array Technology (DArT) markers. Multiple clustering analyses suggest the presence of four subpopulations. Within cultivated barley, substructure is largely centered on spike morphology and growth habit. Analysis of molecular variance indicated highly significant genetic variance among clusters and within clusters, suggesting that the FHB resistant sources have broad genetic diversity. The haplotype diversity was characterized with DArT markers associated with the four FHB QTLs on chromosome 2H bin8, 10 and 13 and 6H bin7. In general, the wild barley accessions had distinct haplotypes from those of cultivated barley. The haplotype of the resistant source Chevron was the most prevalent in all four QTL regions, followed by those of the resistant sources Fredrickson and CIho4196. These resistant QTL haplotypes were rare in the susceptible cultivars and accessions grown in the upper Midwest USA. Some two- and six-rowed accessions were identified with high FHB resistance, but contained distinct haplotypes at FHB QTLs from known resistance sources. These germplasm warrant further genetic studies and possible incorporation into barley breeding programs.     

Plant morphological traits associated with field resistance to cardamom thrips (Sciothrips cardamomi) in cardamom (Elettaria cardamomum)

Cardamom thrips (Sciothrips cardamomi) is a major insect pest of cardamom (Elettaria cardamomum) causing severe economic losses to the crop in all cardamom producing countries. The present control measures rely heavily on chemical insecticides, which in addition to increased input costs also lead to pesticide residues in the produce and environmental hazards. Although the crop is of high commercial value, limited efforts have been made to identify sources of resistance to this major pest. Exploiting sources of resistance along with integrated pest management tactics will help to reduce pesticide usage in this crop promoting sustainable production. The present study aimed at identifying sources of resistance against cardamom thrips and the associated plant morphological traits conferring resistance against the pest. Field screening of 180 cardamom germplasm accessions for 3 years at Appangala, Karnataka, India, resulted in identification of eight accessions resistant to cardamom thrips. Differences in panicle type and the nature of adherence of leaf sheath to the pseudostem explained a significant amount of the variance in resistance and therefore are likely to play a major role in conferring resistance against this pest. Multiple regression analysis of the different traits indicated that accessions with prostrate panicles having leaf sheath loosely adhered to the pseudostems were found to have significantly less thrips damage, when compared with other panicle and leaf sheath types. However, persistence of flower bract did not have a significant additive effect on imparting resistance against thrips. Metabolomic analysis of the accessions may provide further insight into the existence of supplementary biochemical mechanisms, if any, in imparting resistance. The identified traits and accessions can be exploited in future breeding programmes for developing thrips resistant cardamom varieties.     

The Use of Morphological and AFLP Markers in Diversity Analysis of Linseed

Different methods of genetic diversity measures could give better judgment of differentiating important accessions for growers, germplasm curators and plant breeders. Data of 60 accessions of linseed, mainly from Ethiopia, were used to assess their genetic diversity, employing morphological and amplified fragment length polymorphism (AFLP) methods. Analyses of genetic distance, principal components and clusters showed the presence of a wide range of diversity among the studied accessions. The mean for genetic distance estimates of the entire 1770 pairwise accessions was 0.6684 for morphology, while that of AFLP was 0.5734. These genetic distances varied from zero to one for morphology in contrast to 0.29 to 0.71 of the AFLP. Morphological and AFLP based clusters and their accompanying analyses showed different hierarchical patterns of genetic diversity among the accessions. Despite their disparity, the two diversity measures were found independently useful for assessing the degree of relatedness and the overall patterns of genetic variation among the analysed linseed accessions.     

小麦种质对麦长管蚜的抗性鉴定与评价

2002-2005年连续4年,选用蚜情指数法对小麦种质进行麦长管蚜田间自然感蚜抗性鉴定,从2000份小麦种质中筛选出不同抗性材料34份,占总鉴定材料的1.7%,其中高抗种质5份、抗性种质9份、中抗种质20份。利用苗期室内接虫法,对部分抗感小麦种质进行鉴定,结果表明,苗期的抗性表现与成株期基本一致。对杂交组合临远207(抗)×Witchita(感)的F1、F2的抗性遗传分析表明,临远207对麦长管蚜的抗性由1对显性单基因控制。     

美国花生微核心种质资源纯化系的引进与表型评价

花生种质资源是花生新品种选育和重要农艺性状遗传研究的基础材料。引进国外优异花生种质资源,并对其进行鉴定和评价对发掘优良花生种质、丰富我国花生资源遗传多样性以及合理利用种质资源进行遗传改良具有重要意义。本研究于2014-2015年连续2年在河北保定对104份引进的美国花生微核心种质资源纯化系进行了农艺性状考察和抗病性鉴定。鉴定结果表明,美国微核心种质纯化系多为匍匐型,主茎高变异范围为24.50~89.50 cm,侧枝长为39.37~99.23 cm,单株果数和单株果重分别为8.75~46.33个和8.49~29.54 g,百果重为80.76~216.72 g,单株粒数为18.25~58.00个,单株粒重为9.89~33.36 g,百仁重为25.52~74.18 g,出仁率为52.58%~76.08%。抗病性鉴定表明,部分美国微核心种质资源纯化系高抗褐斑病和网斑病,性状优良。该研究结果为花生新品种选育与遗传研究提供了优异材料和参考信息。     

Susceptibility of fruit from diverse apple and crabapple germplasm to attack by plum curculio (Coleoptera: Curculionidae)

Plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), is an important apple, Malus domestica Borkh., pest that significantly hinders sustainable apple production in eastern North America. The potential for host plant resistance to plum curculio among apple germplasm has never been rigorously evaluated. Thus, studies were conducted to assess the susceptibility of a number of exotic and domestic Malus accessions housed at the USDA Plant Genetic Resources Unit (PGRU) "core" collection in Geneva, NY. Contrary to earlier published reports and promising data from a field assessment in 2005, these results suggest that there is probably little potential for genetic resistance to plum curculio among the Malus germplasm collection evaluated. More specifically, four Malus hybrid selections that have previously been released with claims of plum curculio resistance were shown to be susceptible to plum curculio attack. Because there are additional accessions housed at PGRU outside of the core collection that are currently classified as resistant, further studies are necessary to evaluate the true resistance qualities of these releases. It is also important to clarify such discrepancies in both the USDA online Germplasm Resources Information Network and in the horticultural literature. Although other Malus species exhibited some variability in fruit susceptibility, none could be classified as being truly resistant to plum curculio attack by any definition that would have relevance to commercial production and sale of apples.     

Morphological and molecular screening of French bean (Phaseolus vulgaris L.) germplasm using SCAR markers for Colletotrichum lindemuthianum (Sacc. and Magn.) Scrib. causing anthracnose resistance

This study was carried out to screen Phaseolus vulgaris L. germplasm accessions for anthracnose resistance genes to the fungus Colletotrichum lindemuthianum. (Sacc. and Magn.) Scrib. This fungus is made up of many pathogenic races which poses a challenge in developing resistant plant varieties; however, screening for and selection of resistant plant sources plays an important role in developing resistant plant lines. This screening work involved examining 69 accessions consisting of two resistant lines (D-line, L-line) and two susceptible varieties (Kanchana and Jwala). Fourteen SCAR primers specific to anthracnose disease resistance in the French bean were used. Of these 14 SCAR primers, 5 of them, SAS13, SF10, SC08, SZ04 and SBB14, produced amplification with good monomorphic bands.