Accuracy of within‐ and among‐family genomic prediction in triticale

Genomic prediction has emerged as a powerful genomic tool to assist breeding of complex traits. In this study, we employed a population of 647 triticale doubled haploid lines derived from four families to assess the potential of this approach for triticale breeding. All lines were phenotyped for grain yield, thousand‐kernel weight, biomass yield, plant height, frost tolerance and Fusarium head blight resistance. The obtained prediction accuracies were moderate to high and consisted to varying degrees of within‐ and among‐family variance, in line with the different degrees of phenotypic differences between family means. The prediction accuracy within individual families also varied with the genetic complexity of the traits and was generally highest based on effect estimation with lines from the respective family, whereas the prediction accuracy decreased with decreasing relatedness among the families. Taken together, our results illustrate the potential of genomic prediction to increase selection gain in triticale breeding, but the composition of the training set is of utmost importance, and consequently, the implementation of this approach in applied breeding programmes is not straightforward.     

马尾松半同胞子代材性遗传变异分析

以贵州省都匀种子园子代测定林的28个半同胞家系的木材样品为材料进行子代测定,研究其基本密度和纤维长和宽等材质性状以及灰分、1%Na OH抽提物、纤维素、综纤维、木质素等5种木材化学组分的遗传变异规律。结果表明:化学组分中除木质素含量外,其他平均值均高于对照组。灰分含量和木质素含量在家系间差异极显著。化学组分中除木质素和灰分外,1%Na OH抽提物、纤维素、综纤维的遗传力均在0.1801~0.2931之间,均小于0.5,说明其均受中等强度以下的遗传控制。通过对半同胞家系主要材性性状聚类分析,选择出8个优良的纸浆材家系。     

马尾松半同胞家系子代林早期生长差异分析

以湖北省京山县太子山林场管理局马尾松无性系嫁接种子园半同胞8年生子代林为研究对象,在对胸径、树高、枝下高、冠幅和材积等生长因子进行实地调查的基础上进行遗传力分析.结果表明:不同半同胞家系林木各生长因子之间存在极显著性差异,显示马尾松半同胞家系林木间存在较为丰富的遗传变异,具有较大的选育潜力;8年生马尾松半同胞家系子代林树高、胸径和材积的遗传力分别为0.7436、0.6055和0.6500;采用20%的入选率时,筛选出5个优良半同胞家系且入选半同胞家系的材积、树高和胸径遗传增益分别为51.34%、17.45%和22.19%.     

凡纳滨对虾全同胞家系的建立及生长比较

全同胞家系是遗传分析的重要材料。采用自然交配法建立了62个凡纳滨对虾第一代全同胞家系,对其中17个家系进行了比较研究。结果表明,各家系的孵化率、出苗率与雌性亲本的大小相关性不显著。17个家系中有7个家系显示生长优势,其大小顺序依次是A02＞A11＞A01＞A17＞A06＞A08＞A16;7个家系在40周内的生长速度较17个家系的平均值高23.2%。在所有家系中,A01、A02、A11等3个家系的体重显著大于其它家系（P＜0.05）,其平均生长速度较所有家系平均生长速度分别快25.5%、31.6%和31.0%。这3个家系的整齐度良好,在养殖中期的个体变异系数分别为11.58%、9.95%和8.48%,后期均小于5%,显示出优良的经济性状,为进一步选择培育凡纳滨对虾的快速生长新品系奠定了基础。     

Genetic stability analysis of introduced Betula pendula,Betula kirghisorum,and Betula pubescens families in saline-alkali soil of northeastern China

Approximately, 20% of arable land worldwide, as well as nearly half of irrigated land, is subjected to salt stress. Osmotic stress and ion toxicity due to saline soils cause low crop yields. In this study, we introduced 18 families of salt-tolerant birch (Betula pendula Roth., Betula kirghisorum Sav.-Ryczg., and Betula pubescens Ehrh) into five high-salinity locations in northeastern China and evaluated their survival abilities. We also analyzed variation and stability of genotype–environment interactions of the different families under an additive main effect and multiplicative interaction model. Survival rate analysis indicated that the introduced families were well adapted to the high-salinity environments, whereas native families died. Variation analysis revealed significant differences between location × family interaction mean values for height and basic stem diameter (BSD), suggesting that most genotypes responded differently to different sites. The heritability of tree height and BSD at different sites varied from 0.416 to 0.940, with the coefficient of phenotypic variation ranging from 9.88% to 35.53%. Stability analysis indicated that some families had high tree heights but were sensitive to environmental conditions, whereas others were resistant but had average tree heights. These results suggest that families should be bred in various habitats to assess growth under favorable and unfavorable environments.     

新疆阿尔泰地区白杨派3个树种半同胞家系子代遗传多样性分析

利用SSR分子标记技术,对采自新疆额尔齐斯河流域阿尔泰市哈巴河及北屯地区的白杨派3个树种银白杨、银灰杨、欧洲山杨的半同胞家系子代进行遗传多样性分析.结果表明:筛选12对SSR引物在90个样本中共检测到58个等位基因(A)、112种基因型,多态位点百分率是100％,Nei遗传多样性指数(h)平均为0.648 5,Shannon多样性指数平均为1.234.基因分化系数(Fst)为0.337 l,即在总的遗传变异中有33.71％的变异来自于不同树种之间,绝大部分存在于子代个体间.白杨派内种间分化程度较高,种间遗传距离为0.3863～1.869;银灰杨的遗传变异最大,而银白杨的遗传变异最小.     

高校家庭经济困难女生科学发展的现状调查与思考——以福建部分高校为例

高校家庭经济困难女生是一个特殊的学生群体。通过调查了解她们发展中面临的困扰，分析指出促进她们的科学发展，应改进经济资助，强化精神扶持；增进人际交往，提高社会化技能；以学习为先，素质拓展为重；加强心理援助，妥善干预。     

一球悬铃木优良家系的评选

对1999年引自美国的12个种源47个一球悬铃木半同胞家系子代进行了综合评定,在5个试验点分别筛选出了适应性强的优良家系.虽然对4、5年生的一球悬铃木进行选择的结果不尽相同,但诸如松江点的10、16,镇江点29、36等5个试验点的21个优良家系表现是相对稳定的,而14和36号家系则适应范围更广.5个试验点的优良家系多来...     

Resistance of genetically different common carp, Cyprinus carpio L., families against experimental bacterial challenge with Aeromonas hydrophila

The objective of this study was to determine the differences in disease resistance against artificial infection with Aeromonas hydrophila between genetically different common carp families. Four strains differing in their origin and breeding history were selected from the live gene bank of common carp maintained at the Research Institute for Fisheries, Aquaculture and Irrigation (HAKI, Szarvas, Hungary) to establish families with wide genetic background: Szarvas 15 (15), an inbred mirror line; Tata (T) scaly noble carp; Duna (D), a Hungarian wild carp and Amur (A), an East Asian wild carp. A diallele mating structure was used to allow the assessment of genetic variation within and between the tested 96 families for a variety of traits. The existing technologies of fertilization and incubation of carp eggs, as well as larval and fingerling rearing had been modified because of the large number of baseline populations. Two challenge trials of the 96 families of carp with Aeromonas hydrophila were done. The 10 most resistant and 10 most susceptible families to A. hydrophila were identified from these two challenges. The crosses that produced the most resistant families were mainly those having parents from Tata and Szarvas 15 domesticated strains, while the most susceptible families were from the wild strains Duna and Amur.     

Multigene Families of Powdery Mildew Resistance Genes in Locus Mla on Barley Chromosome 5

A review of data on powdery mildew resistance genes in the Mla locus of barley reveals that there are at least 12 clusters of genes present, each comprising one Mla gene and one or more closely linked, additional resistance genes. Tentative designations are listed for 16 additional resistance genes. Many sources of powdery mildew resistance in barley appear to harbour multigene families in the Mla region, not single ‘superior’genes.