水稻细菌性褐条病病原的鉴定

为明确从褐条病稻苗上分离出来的病原细菌并与西瓜果斑病菌相区分, 对该病原特性进行了研究。分离获得6株褐条病致病菌,其中4株经主要细菌学特性、菌落形态、致病性、Biolog、脂肪酸分析（FAME）、电镜观察、Nested PCR鉴定及与3株水稻细菌性褐条病标准菌株和2株西瓜果斑病标准菌株的比较,证实了该病是由单极鞭革兰氏阴性细菌〖WTBX〗Acidovorax avenae〖WTBZ〗 ssp. 〖WTBX〗avenae〖WTBZ〗引起的。FAME将水稻细菌性褐条病菌误鉴定为西瓜果斑病菌,而用Biolog和nested-PCR鉴定能得到准确的鉴定结果。     

不同来源地茶树种质资源表型性状遗传多样性分析

为了对不同来源地茶树种质资源进行鉴定评价和遗传多样性分析,以来自福建、广东、台湾的72份茶树种质作为研究对象,对其27项表型性状进行观测与分析。结果表明：72份茶树种质资源遗传变异性丰富,平均遗传多样性指数（H′）为1.30,其中数量性状（1.82）大于质量性状（0.94）,以梗粗的最大（2.15）;数量性状的平均变异系数（CV）为17.86%,以百芽重的最大（29.21%）,其次是发芽密度（23.46%）。相关性分析发现多个数量性状间的关系复杂,有22对性状的相关性达极显著水平（P˂0.01）,8对达显著水平（P˂0.05）;聚类分析结果显示,72份茶树种质在遗传距离为16时被划分为4个类群,各类群间的主要性状差异显著或极显著,且形态特征和进化类型各异;主成分分析表明,前10个主成分的特征值大于1,代表了27项表型性状76.04%的信息;根据主成分综合得分大小,筛选出综合得分前5的茶树种质可在茶叶新产品开发、茶树育种等方面加以利用。     

77份文心兰种质资源表型性状遗传多样性分析

对文心兰77份种质资源的28个表型性状进行测定与评价,通过相关性分析、主成分分析及聚类分析获得其表型遗传多样性.结果表明:21个数量性状的遗传多样性指数均值达1.85,变化区间为1.36～2.07,其中数值最大为株幅(2.07);在7个质量形状中,除叶色性状外的其他表型性状的多样性指数均大于1,均值为1.23,最大表现...     

滇重楼及其近缘种的表型变异与资源评价

以滇重楼及其近缘种为对象,通过表型性状调查结合多元统计分析,研究重楼属药用植物的表型变异及各性状对药材产量的影响。结果显示：16个表型性状中,株高、茎粗、叶形、叶宽、叶柄长等性状变异较大（CV值大于40.00%）,萼片长、萼片数、花瓣数种间变异较小（CV值均小于25.00%）。5种重楼属植物表型性状的遗传多样性指数（H°）为2.03~0.82;滇重楼和多叶重楼性状的遗传多样性指数平均值最高。主成分分析结合偏最小二乘-判别分析显示,多叶重楼、滇重楼的叶部和花部位性状与其他物种差异较大;南重楼和西畴重楼的株高、茎粗、叶宽、根茎长、根茎直径、根茎鲜重与其他重楼属物种差异明显;5种重楼属植物中南重楼与西畴重楼形态最接近,较难区分。相关性分析表明,重楼属植物地上性状与地下性状呈显著或极显著的正相关（P<0.05或P<0.01）;进一步利用变量投影重要性指标分析发现,根茎直径、根茎长、叶柄长、叶长、叶宽、花梗长、株高和花瓣长是筛选药用重楼高产种源的关键性状。     

Establishment of core collection for Chinese tea germplasm based on cultivated region grouping and phenotypic data

Tea is an important economic crop in China. About 2665 accessions of tea germplasm (Camellia spp.) are conserved in the China National Germplasm Tea Repository. However, only a small fraction of the collections have been exhaustively used in tea plant improvement programs. The objective of the present study was to develop a core collection of tea plant to enhance the utilization of genetic resources in improvement programs and simplify their management. For this purpose, based on the cultivated region grouping and phenotypic trait data, a core collection of tea plant was established using logarithm proportion and Ward’s cluster method. Approximately 20% of the accessions were then randomly selected from these distinct groups to form a core collection of 532 accessions. Different statistical methods including comparison of mean using Newman-Keuls test, variance using Levene’s test, and frequency distribution using Chi-square test for the traits validated that the variation present in the initial collection was retained in the core collection. The Shannon-Weaver diversity index for different traits was also similar in the core and initial collection. The phenotypic correlations among different quantitative traits that may be under the control of coadapted gene complexes were also preserved in the core collection. This core collection will play an important role in the utilization of tea germplasms.     

云杉天然群体表型性状频率分布及多样性研究

为探索云杉天然群体表型性状的频率分布特征,及其在频率水平上的表型多样性,根据性状值大小分组统计频率,绘制频率分布图,应用频率数据计算各群体的多样性指标值：表型多样度（Dp）和表型Shannon信息指数（Ip）,用多重比较与PCA主成分分析对10个群体分类。频数分布分析结果显示：云杉群体的表型性状数据基本符合正态分布;根据DP和IP对群体排序,按群体多样性从大到小依次为阿坝、卓尼、林坡、铁布、热务沟、黑水、巴西、川盘、大录、小金。多重比较与PCA主成分分析结果表明,云杉10个天然群体可分为3类,其中第1类的小金、热务沟群体的表型频率多样性较低,但性状值较大,位于云杉分布区的南部;第2类的7个群体表型频率多样性较大至中等,性状值较小至中等,位于云杉分布区的中部和北部;第3类的阿坝群体表型频率多样性最大,性状值偏小;DP和IP相关极显著（r=0.995）。     

顶坛花椒结实性状表型多样性分析

以贵州花江峡谷地区特有经济树种顶坛花椒为研究对象,按海拔、坡向因素选取3个群体32个单株,调查了9个结实性状,采用多重比较、变异系数、相关分析、聚类分析等方法,分析顶坛花椒结实性状的多样性及群体间和群体内的变异特征和变异规律。结果表明,顶坛花椒结实性状在群体间和群体内均存在丰富的变异。3个群体9个性状的平均变异系数为29.81%（17.36%~50.96%）,9个形态性状的平均变异系数由大到小的顺序依次为果穗果粒密度（47.56%）>果穗果粒数（44.43%）>枝条结果部位长度（33.71%）>果穗宽（28.75%）>果枝直径（25.21%）>果穗长（24.61%）>果枝长宽比（22.54%）>果穗长宽比（21.23%）>果枝果穗密度（20.20%）,表明果枝果穗密度和果穗长宽比较为稳定,而果穗果粒密度和果穗果粒数稳定性较低。相关分析表明,果穗性状和枝条性状间无显著相关关系。聚类分析表明,顶坛花椒结实性状的变异无空间特异性。为顶坛花椒种质资源的评价、利用及遗传改良提供了依据。     

52份茶树资源生化组分的表型多样性分析

对四川地区33个和从省外引进的19个茶树资源的主要生化成分（包括水浸出物、茶多酚、氨基酸、咖啡碱、儿茶素总量、酯型儿茶素总量、简单儿茶素总量等）进行鉴定和多样性分析。结果表明：参试的茶树资源生化组分存在丰富的多样性和变异;并以茶树资源生化成分为基础,可将52份茶树资源分为A、B两个组群。     

Are more productive varieties of Paspalum dilatatum less tolerant to drought?

Paspalum dilatatum Poir., is a perennial C₄ grass widely distributed in the Argentinean Pampas. The response to water availability for materials developed with forage‐production purposes is unknown. We hypothesized that genetic differences between commercial varieties are reflected in their regrowth capacity under water stress. The effect of five levels of constant water supply on three plant varieties (two derived from apomictic materials: ‘Relincho’ and ‘Alonso’ and one from sexually‐derived material: ‘Primo’) were examined in the greenhouse. Leaf‐ and plant‐response traits were followed during 38 d after a single defoliation event. Seven response variables were measured: three of them were morphogenetic (leaf elongation rate, leaf appearance rate and leaf elongation duration) and four were structural (number of live leaves, lamina length, tiller biomass and tiller production). The sexual material showed higher values for growth variables than the apomictic varieties (leaf elongation rate, leaf length and tiller biomass) across the environmental range. Apomictic varieties showed a proportionally similar drought response to the sexual material for the seven variables. No intra‐specific trade‐off (statistical interaction) was found between growth under high water availability conditions and drought tolerance.     

豫州褐壳蛋鸡各品系主要经济性状间的相关分析

本文用多变量相关分析和通径分析方法，对豫州褐壳蛋鸡５个品系产蛋性能方面的性状进行相关分析，结果表明，将开产日龄，４０周龄平均蛋重和４０周龄产蛋数，作为蛋鸡早期选种指标是适宜的。