几种简化动物模型评定种畜育种值的BLUP法计算效率比较     

宫本一 《河北农业大学学报》1990,13(3):105-113

本文论述了利用简化动物模型评价种畜育种值的最佳线性无偏预测(BLUP)法的计算效率。根据本文的模拟数据示例和国外文献资料分析表明,包括父亲和外祖父的简化动物模型与通常的动物模型的BLUP计算比较,对于缩小方程组的大小、节省计算机的内存和减少计算时间等方面的效率都较高,而包括父亲和母亲的简化动物模型的效率不如前者。因此,生产能力测验评价种畜育种值需用较大系列方程时,以采用包含父亲和外祖父的简化动物模型的BLUP法为宜。  相似文献   

计算机在猪育种分析中的应用与实现方法研究     

杨泽明  熊远著  雷明刚  夏宣炎  苏玉虹 《农业工程学报》2001,17(7):67-70

阐述了计算机在猪育种分析中的应用，并结合数据流程研究了猪育种分析的微机实现方法。采用目前最流行的面向对象的事件驱动编程技术，编制成了“所见即所得”的“傻瓜化”育种分析软件。软件实行全中文化的界面化程序设计和人机对话的操作模式，利用Visual FoxPro关系数据库管理语言，对数据进行收集，整理，贮存，分析，决策。其中用Microsoft Fortran语言编写了BLUP法估计育种值计算程序，近交系数和血缘相关计算程序。  相似文献   

Genetic and statistical models for estimating genetic parameters of maize seedling resistance to Fusarium graminearum Schwabe root rot     

J. Moreno-González  J.L. Andrés Ares  R. Alonso Ferro  L. Campo Ramírez 《Euphytica》2004,137(1):55-61

Root lodging is an important problem in corn fields. Fungi recovered from roots include seedling blight and stalk rot pathogens. The objective of this work was to study the inheritance of maize seedling resistance to pathogens causing maize lodging. The Fusarium graminearum strain, 241 Fr1, was isolated from maize lodged plants and identified as the most pathogenic isolate for root rotting. Nine inbred lines of maize and their diallel F₁ crosses plus control genotypes were studied. Seedlings were inoculated at the stage of four-leaves. Disease severity was measured as percentage of the root rotted area. Highly significant differences between inoculated and non-inoculated genotypes were found. Four genetic models and two statistical approaches—the mixed model for the best linear unbiased prediction (BLUP) and the general linear model (GLM)—were used for the analysis. Favorable heterosis of resistance of hybrids over inbreds was the most important effect detected. The general combining ability (GCA) effects were significant for all genetic models and statistical methods studied, and a good agreement existed among the GCA estimates by the different methods. The type of gene action, either additive or dominance, showed a large variation among the parental inbreds and hybrids. Selection of additive effects based exclusively on inbred lines is not sufficient to confer resistance to hybrids, additional selection should be practiced on hybrids to look for favorable dominance effects. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Genotype × Environment Interacion in multi-environment Trials using shrinkage factors for ammi models     

J. Moreno-González  J. Crossa  P.L. Cornelius 《Euphytica》2004,137(1):119-127

Shrinkage factors applied to the additive main effects and multiplicative interaction (AMMI) models improve prediction of cultivar responses in multi-environment trials (MET). Estimates of shrinkage factors based on the eigenvalue partition (EVP) method may get a further improvement in the predictions of cell means. Objectives of this work were: (1) to compare the EVP-based shrinkage method with unshrunken AMMI, best linear unbiased predictor (BLUP) and other shrunken method (herein named CCC), when they were applied to five maize MET and simulation data; (2) to assess by cross validation the equation which estimates the standard error of predicted means (SEPM) based on the EVP theory; (3) to estimate the genotype × environment interaction (GEI) variance components after applying the EVP shrinkage method to the five maize MET. Empirical data of five maize MET and simulation data were used for cross validation of the methods using the root mean square predictive difference (RMSPD) criterion. The RMSPD of the shrunken EVP predicted cell means was generally smaller than those of the other methods, suggesting that the EVP method was generally better predictor than the other methods. The truncated AMMI was the worst among the four methods studied. The EVP-based equation, which predicts the SEPM, was a good predictor as determined by the RMSPD cross validation criterion, with the advantage that it does not need one replication for validation. Estimates of mean squares, and GEI and error variances associated with the GEI effects were smaller for the shrunken EVP predicted effects than for the original data. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Genomic selection in hybrid breeding          下载免费PDF全文

Yusheng Zhao  Michael F. Mette  Jochen C. Reif 《Plant Breeding》2015,134(1):1-10

While hybrid breeding is widely applied in outbreeding species, for many self‐pollinating crop plants, it has only recently been established. This may have had its reason in the limitations of methods available for hybrid performance prediction, in particular when established heterotic pools were absent. Genomic selection has been suggested as a promising approach to resolve these limitations. In our review, we briefly introduce the principles of genomic selection as an extension of marker‐assisted selection using genome‐wide high‐density molecular marker data and discuss the advantages and limitations of currently used algorithms. Including the outcome from a recent extended approach to hybrid wheat as a timely example, we summarize current progress in empirical studies on the application of genomic selection for prediction of hybrid performance. Here, we put emphasis on the factors affecting the accuracy of prediction, pointing in particular to the relevance of relatedness, genotype x environment interaction and experimental design. Finally, we discuss future research needs and potential applications.  相似文献   

中国西门塔尔牛产奶量育种值不同估测方法的比较研究   总被引：2，自引：0，他引：2  

陈幼春  贾恩棠 《中国农业科学》1993,26(4):71-78

 奶的产量是西门塔尔牛第一个重要经济性状。该性状育种值的估测自1980年开始，以谱系育种值的方法在一个场内示范，再在其他各场展开。1984年向中国西门塔尔牛育种协会引入预期差（PD#-74）法，1985年引入最佳线性无偏预测（BLUP）法。在综合解决了遗传力（h#+2）和环境相关（C#+2）两参数的估测方法后，PD法作为产奶量的测定可以适用于有亲缘关系和环境条件迅速改进的条件。BLUP法和PD法的结果可以相互印证，两种育种值的Spearman相关系数r#+2=0.8，说明都可以应用。而BLUP法对具有亲缘关系的种畜在估测时更为敏感。良种登记母牛产奶量十年内从3375千克提高到5152千克。初步估算，一个世代遗传进展是138千克。  相似文献   

Heritability for body weight at harvest size in the Pacific white shrimp, Penaeus (Litopenaeus) vannamei, from a multi-environment experiment using univariate and multivariate animal models     

Héctor Castillo-Juárez  Juan Carlos Quintana Casares  Cesáreo Cabrera Villela  Hugo Horacio Montaldo 《Aquaculture (Amsterdam, Netherlands)》2007,273(1):42-49

To estimate family BLUP breeding values and the heritability of body weight at harvest size (BW) in the Pacific white shrimp, Penaeus (Litopenaeus) vannamei, an experiment was conduced using information from two farm units of a Mexican hatchery and two shrimp population densities at each location. Data consisted of 12,658 shrimps that were siblings from 48 sires and 77 dams with a nested dam-sire structure. Shrimps were individually weighed at an average age of 130 days post-hatching. BW phenotypic mean (S.D.) was 18.2 (2.4) g, with values ranging from 8.4 to 30.0 g. Data were analyzed using univariate and multivariate models that considered BW within location by density pond environment as a different trait and included or not a common full-sib effect (c). The multivariate animal model included fixed effects of days from hatching and sex. For univariate models that included c effects, BW heritability (S.E.) estimates ranged from 0.24 (0.14) to 0.35 (0.18) across environments (heritability was zero in one environment). For multivariate models (excluding the environment with zero heritability) the heritabilities increased and ranged from 0.37 (0.06) to 0.45 (0.09). Standard errors of heritabilities and c effects were both drastically reduced in the multivariate analysis. Pairwise genetic correlations between environments were from 0.80 (0.08) to 0.86 (0.04). These differences may be indicative of genotype-environment interaction for BW at 130 days post-hatching. Statistical problems found to separate c from additive genetic effects both in univariate models were reduced using multivariate models. Correlation between family raw phenotypic means and family BV means from the multivariate analysis was 0.93 indicating a rather low risk of miss selecting superior families if BLUP solutions were neglected using replicated environment data. It is also concluded that use of incorrect statistical models or unreplicated data may lead to biased or inaccurate estimates of genetic parameters in shrimp breeding programs.  相似文献   

应用布拉普法选择南阳公牛的研究(下)     

王勇强  刘孟强  朱宽佑  杨健  高腾云  王冠立 《郑州牧业工程高等专科学校学报》1993,(2)

应用单性状布拉普(BLUP)育种值估计及方差组分的约束极大似然估计,评价了南阳黄牛场近年使用的9头南阳黄牛种公牛的优劣秩次,估出断奶(8月龄)体高、体斜长、胸围、管围及坐骨端宽的遗传力分别为O.3813、0.5960、O.3738、O.3730和0.3355,1988～1992年5年间各性状年平均遗传进展分别为0.0043、0.2947、0.0193、0.0007和0.0059。  相似文献   

Sustainable plant breeding     

Wallace A. Cowling 《Plant Breeding》2013,132(1):1-9

Plant breeders disrupt Hardy–Weinberg equilibrium through selection, non‐random mating, drift, migration and mutation. Sustainable plant breeding can be defined as productive and competitive breeding that is achieved without loss of genetic diversity in the elite breeding population during the professional career of the breeder. Breeding is often productive but not sustainable. From 1974 to 2000, the animal breeding programme Meatlinc in the United Kingdom had effective population size of 95, population inbreeding of 0.19% per year and generation interval of 2.15 years. Genetic progress in Meatlinc tripled in the 8 years following introduction of best linear unbiased prediction (BLUP) selection (based on the information from relatives) in 1992. Canola breeding in Australia from 1970 to 2000 had longer generation interval (6 years), smaller effective population size (<11) and higher rates of inbreeding (>0.7% per year). BLUP selection in canola was first reported in 2010. Neither programme replaced genetic diversity lost through selection and drift. Most breeding programmes violate conditions of the infinitesimal model, thereby reducing predictability of selection, but breeders can minimize these limitations to sustainable plant breeding.  相似文献   

林木育种值预测方法的应用与分析   总被引：3，自引：1，他引：2  

孙晓梅  杨秀艳 《北京林业大学学报》2011,33(2):65-71

育种值预测是遗传评价的核心。为了能恰当地选用适当方法估算林木育种值,本文概述了当前林木育种值预测的主要方法、原理及其在日本落叶松家系（亲本）及个体育种值预测和优良基因型选择中的应用。通过对各种预测方法应用结果的分析表明:对于平衡或近似平衡数据和无亲缘关系（或可忽略）的非平衡数据,最佳线性预测（BLP）、最佳线性无偏预测（BLUP）法均可以取得很高的预测精度,但考虑到计算的简便性,BLP法更为适用;对于有亲缘关系或具有不同遗传固定效应的候选材料,BLUP法更为适用;对于多性状联合选择,选择指数仍是理想的方法。最后对育种值预测方法的适用情况及存在问题进行了讨论。   相似文献