Inheritance of equine sarcoid disease in Franches-Montagnes horses

The mode of inheritance for susceptibility to equine sarcoid disease (ES) remains unknown. The objectives of this study were to analyse a large sample of the Franches-Montagnes (FM) horse population and investigate the heritability and mode of inheritance for susceptibility to ES. Horses were clinically examined for the presence of sarcoid tumours. A standardized examination protocol and client questionnaire were used and a pedigree- and subsequent segregation-analysis for the ES trait performed. To investigate the mode of inheritance, five models were evaluated and compared in a hierarchical way.The analyses reveal that variation in susceptibility to ES is best explained by a model incorporating polygenic variation. The possible effect of a major gene, such as specific equine leukocyte antigen alleles, is unlikely, but cannot be ruled-out entirely. The heritability of the phenotype on the observation scale for the trait ‘affected with ES’ was estimated to be 8%. A corrected value for the heritability on a liability scale was estimated at 21% and it is therefore possible to estimate breeding values for ES. The arguments against the practical implementation of an estimated breeding value in a multifactorial condition like ES are discussed.     

结球甘蓝主要商品性状与农艺性状的遗传相关分析

以6个甘蓝亲本进行完全双列杂交,采用加性-显性遗传模型对结球甘蓝的主要商品、农艺性状进行遗传分析。结果表明:各性状的遗传同时受加性效应和显性效应的作用,株高、外叶数主要受加性效应控制;开展度、单球重、帮叶比、中心柱/球高主要受显性效应控制。相关分析表明,开展度-株高、开展度-单球重、外叶数-帮叶比等成对性状成显著正相关,利用株高可对帮叶比、中心柱/球高进行间接选择。     

杉木种子园中无性系间结实和种子品质差异研究

在观察的31个无性系中丰产的约占20％,产量约占总产30％;中等的占60％弱,产量占54％;低产的占20％强,产量约占17％。结实的广义遗传力hw~2平均0.66。不同无性系在雌雄花比、雌花序结构、球果大小和分枝稠密度等方面存在差异。一般植株“偏雌性”、聚生雌花序占优势,球果大、树冠表面积大而分枝稠密的无性系结实量高;反之,“偏雄性”、单生雌花序为主、球果小、树冠表面积小而分枝稀疏的无性系结实量低。据72个无性系的分析,大粒种子无性系约占21％,中粒的约占47％,小粒的占32％;高发芽率无性系占23.6％,中发芽率的占57％,低发芽率的占19.4％。大粒种子无性系的发芽卒往往高于中、小粒种子无性系;而发芽势有相反趋势。     

Standard errors of heritabilities based on perennial observations,with application to Yorkshire Fog grass

Summary The variance of heritability ratios are considered for cases where data from perennial genotypes are collected serially over time. A random effect model for randomised complete blocks at a single location is examined. Estimation of the variance of estimates of heritability is presented for three types of heritability definition.Estimators are applied to two characters in a Yorkshire Fog grass germplasm collection evaluated for two years at one site. The precision of such heritability estimates is discussed. Estimators for the multiple sites model are available also, from the author.     

三交水稻的育种研究Ⅲ.三交中晚稻主要农艺性状的配合力和遗传力分析

用4个纯合不育系菲A、中9A、金23A和珍汕97A，4个杂合不育系菲A/协青早B、中9A/协青早B、金23A/协青早B和珍汕97A/协青早B，3个恢复系752、测64-7和优米2号，按8×3 NCⅡ交配设计对16个性状的配合力进行分析。结果表明，所有性状的一般配合力和特殊配合力均达到了显著或极显著水平。在播始历期、穗长、千粒重、结实率、有效穗     

Genetic and Environmental Factors Influencing Gestation Length in Lusitano Horses

Breeding and parturition records collected over a period of 35 years in the Alter Real stud of Lusitano horses were used to calculate gestation length (GL). The 1027 gestations by 209 mares mated to 60 stallions had a mean GL of 338.1 ± 9.26 days. The mixed model analysis of variance indicated that the sex of the foal and inbreeding of the dam and foal had no significant effect on GL (P > .05). On the other hand, GL increased linearly with mare age, with an estimated regression coefficient of 0.155 ± 0.069 days/year (P < .05). Year and conception month affected GL (P < .05), with longer gestations observed when breeding occurred between January and April, followed by a decline of about 5 and 10 days in GL of mares bred in May and in June–July, respectively. Important differences were observed between stallions (P < .05), with most stallions resulting in a distribution of GL in an interval of ±5 days. The inclusion of the mare as a random effect in the mixed model resulted in an estimated repeatability of GL of 0.427, indicating that mares tend to be regular in having long or short gestations across their lifetime. Variance components estimated in an Animal Model resulted in heritability estimates of 0.39 for maternal genetic effects and 0.19 for direct genetic effects, with no association between the two components. Overall, the mare seems to have the major genetic influence on GL in Lusitano horses, but environmental factors, such as month of conception and also the age of the mare, have a noticeable effect.     

春小麦主要性状配合力及遗传力的初步分析

为了解春小麦品种主要性状的遗传力和杂交亲本的配合力,按Griffing的第2种双列杂交设计方案对8个春小麦品种的6个主要性状进行了配合力测定。其结果为:6个性状的两种配合力的方差均达5%显著水准,一般配合力方差明显大于特殊配合力方差。不同亲本、不同性权的配合力差异较大。一般地说,某个性状值高,其一般配合力也高。同时估算了6个性状的广义遗传力和狭义遗传力。     

割手密始花期的遗传研究与利用参考

[目的]为甘蔗“高贵化”杂交制种提供理论依据,充分利用甘蔗野生种质资源.[方法]采用广义遗传力统计分析了112份割手密连续3年始花期的调查资料,同时调查花粉量与结实率,为杂交利用提供参考.[结果]割手密始花期的广义遗传力达0.079.割手密的始花期年际间差异在4～49d之间,平均为13.65 d.年际间变化在20 d内占90％,超过30 d的仅占4.5％.[结论]部分早花割手密经处理后始花期都明显推迟,在杂交季节中必须根据花期变化的实际情况对当年的杂交计划作适当的调整,才能得以充分利用.