茧丝纤度曲线的解析模型及其在模拟缫丝中的应用

建立了一种茧丝纤度曲线的统计解析模型 ,分析其用于模拟茧丝时茧丝纤度曲线的统计特性 ,证明这是一种有利于控制模拟生成的茧丝纤度特性的方法。通过计算机模拟试验讨论其在茧丝纤度曲线模拟及缫丝工程模拟中的应用。     

家蚕主要经济性状间的遗传相关及通径分析

本文对家蚕的主要经济性状进行遗传相关和遗传通径分析。结果表明:龄期经过、虫蛹率、纤度、净度与别的性状无显著的相关关系。茧丝量、茧丝长、解舒丝长表现为结果性状。茧层量是影响茧丝量的最主要因素;茧层量与茧层率对茧丝长的影响基本一致;解舒率及茧丝长对解舒丝长的作用最大。     

不同新用途蚕品种的育成

<正> 一、新育成的蚕品种蚕丝素材的开发,是对茧丝质量要求的多样化。以前较为重视小类,要求茧丝纤度和粒内均方差、茧丝长等性状优良。在蚕丝昆虫研究所,直到现在育成的有作和服用丝原料茧,茧丝纤度3.0D左右的标准纤度蚕品种,有2.0D     

家蚕茧丝均匀度的遗传研究

茧丝的平均纤度及其最大开差、茧丝纤度综合均方差等特征数据和每百回茧丝纤度分布曲线是原料茧的重要特征之一,它关系到缫制生丝的规格、定粒配茧工艺设计、生丝品位(如生丝偏差、总差与均匀一、二度变化)等。家蚕茧丝均匀度与以上茧的特征关系密切,可以认为茧丝纤度及其均匀度是影响生丝规格、生丝品位的一个极其重要的因素。本文在调查一定数量品种的基础上,选取茧丝均匀度较好和较差的品种作为材料,用经典遗传学方法进行茧丝均匀度的遗传及与其它性状间相关性的研究。     

家蚕新品种“苏秀×春丰”原种丝质性状比较

茧丝性状是评价家蚕品种性能的重要指标,中细纤度家蚕新品种"苏秀×春丰"的原种苏秀、春丰分别为中系和日系的二化性固定种,为了比较"苏秀×春丰"原种的茧丝丝质性状,分析不同茧层部位茧丝性能的差异,对两者的茧丝长、茧丝纤度和断裂强力三个指标进行调查研究。结果表明:苏秀、春丰的原种茧丝长分别为1 166.400m和1 132.988m,苏秀的茧丝长较春丰长;两者茧层内外的茧丝纤度在1.2-2.9Dtex,苏秀各茧层位置的茧丝纤度大于春丰;两者茧层内外的茧丝相对断裂强力在182.9-371.7CN/Dtex,相对断裂强力差异不明显。     

茧丝纤度与强伸性能的相关性分析

本实验主要研究家蚕茧丝纤度与强伸性能之间的相关性，结果表明：①家蚕不同品种间茧丝纤度和断裂强力、伸长率的相关系数分剐为0．654、-0．181；②家蚕同一品种不同个体间的茧丝纤度和强伸性能均呈较明显的正（或负）相关性，但未达到显著水平；③同一个体不同茧层的茧丝纤度和强伸性能之间大部分呈显著或极显著正相关。本研究结果初步表明，茧丝纤度与强伸性能之间的相关性大小：不同茧层〉同一品种不同个体〉不同品种。     

粗纤度家蚕品种中205×日206的育成

利用我省现行的实用蚕品种与从日本引进的粗纤度育种材料进行杂交充血基因重组,根据茧丝纤度性状的遗传规律进行定向选择,选育出一对茧丝纤度达4.0D以上的,限性斑纹的,粗纤度家蚕品种中205*日206。     

不同纤度家蚕茧丝的显微结构差异

对 3个不同茧丝纤度蚕品种的茧丝表面及断面结构扫描电镜观察研究 ,发现不仅其纤度大小有极显著的差异 ,而且茧丝切口形态也有很大变化 ,并与生丝的物理性质测定结果相一致。     

粗纤度家蚕品种C华×JD的育成

根据茧丝纤度性状的遗传规律 ,采用直接选择和间接选择相结合的方法 ,育成了 1对茧丝纤度 4 5dtex的粗纤度家蚕品种C华×JD ,其单产达 4 4 2kg/盒种 ,茧丝长 10 0 0m、解舒丝长 70 0m以上 ,适合于生产粗旦生丝。     

中细纤度家蚕新品种“苏秀×春丰”的育成

利用杂交育种及系统选择的方法,育成了具有中细纤度特色的4眠性家蚕新品种苏秀×春丰。经江苏省家蚕新品种实验室鉴定和农村生产试验表明,新品种孵化、眠起、上蔟齐一。实验室鉴定成绩为万蚕茧层量、万蚕产丝量分别比对照品种菁松×皓月提高1.02%和1.28%,茧丝品质性状也优于对照品种,其中茧丝长1525m,解舒丝长1186m,解舒率77.78%,茧丝纤度2.646dtex,洁净93.94分。新品种具有茧丝纤度细、茧丝长、茧丝纤度综合均方差小的特色,适合缫制细纤度高品位生丝。2010年4月该品种通过江苏省蚕品种审定委员会审定,可作为华东地区优质原料茧生产的实用家蚕品种。     

Technical note: use of laser diffraction for particle size distribution measurements in duodenal digesta

Duodenal samples from three lactating cows were used to measure the particle size distribution by wet sieving and by laser diffraction (LD). The median particle size was calculated in the size range where the methods overlapped, and the median particle size was not different between the methods (P = 0.98). The particle size data were also fitted to a log normal distribution function. The logarithmic mean particle size (log10mean) tended to be larger for wet sieving (P = 0.06), and the logarithmic standard deviation (log10SD) was similar for the two methods (P = 0.32). In addition, duodenal samples from the same three animals were fractionated into five different size classes by wet sieving. Particle size distributions were measured by LD and by microscopic image analysis (MIA) for each of the size classes. The log10mean particle size calculated by LD was inside the sieve size range of the four smallest size classes. Log10mean particle size calculated by LD was smaller than log10mean calculated by MIA for two size classes (106 to 300 microm and 300 to 600 microm), and LD gave generally broader particle size distributions than MIA. This study showed that duodenal particle size distributions measured by LD and wet sieving were similar and LD is therefore an alternative method for particle size distribution measurements in postruminal digesta.     

Increased litter size in Rambouillet sheep: II. Expected responses from alternative selection criteria.

The variance and covariance components estimated from an experimental flock of Rambouillet sheep were used to predict response in litter size to direct and indirect selection. Indirect traits considered were ovulation rate and scrotal circumference. Ovulation rate was the most useful indirect selection criterion for genetic improvement of litter size. Expected response in litter size to indirect selection on ovulation rate was 93% as large as the expected response to direct selection on litter size. Selection based on an index of litter size and ovulation rate was estimated to produce 123% as much response in litter size as selection on litter size alone, and selection on an index of litter size, ovulation rate, and scrotal circumference resulted in 133% as much response in litter size as direct selection on litter size.     

超细纤度蚕的农村生产试验

在永康农村进行了超细纤度蚕茧生产试验。结果显示，生产超细纤度蚕茧的三眠蚕诱导率99%以上，全龄经过约21.19 d，较普通四眠蚕缩短约5.56 d；全龄用桑量为普通四眠蚕的39.98%；折算后超细纤度三眠蚕的张种产茧量和产值，较全市普通四眠蚕的平均增幅分别达到10.19%和31.9%；超细纤度蚕茧的解舒率高、丝质优，可缫制6A级最高品位生丝；适时饷食用药以及准确掌握用药量，是确保蚕眠性转化的关键。超细纤度蚕茧生产不仅经济效益高，而且蚕作稳定及可缓和农业与养蚕的劳力矛盾。     

Morphological characteristics of blood cells in monitor lizards: is erythrocyte size linked to actual body size?

Blood cell morphology and count are not uniform across species. Recently, between‐species comparisons revealed that the size of red blood cells is associated with body size in some lizard taxa, and this finding was interpreted in the context of the metabolic theory. In the present study, we examined the numbers and the size of blood cells in 2 species of monitor lizards, the mangrove‐dwelling monitor (Varanus indicus) and the savannah monitor (V. exanthematicus), and we compared these traits in individuals of different body size. The results revealed that during the course of ontogeny, the size of red blood cells increases with body mass. Because the mass‐specific metabolic rate decreases with body size and the cell volume‐to‐surface ratio decreases with the cell size, changes in the erythrocyte size might be the result of oxygen transport adjustment.     

Temperature-induced plasticity at cellular and organismal levels in the lizard Anolis carolinensis

Among ectotherms, individuals raised in cooler temperatures often have larger body size and/or larger cell size. The current study tested whether geographic variation in cell size and plasticity for cell size exist in a terrestrial, ectothermic vertebrate, Anolis carolinensis Voigt, 1832. We demonstrated temperature-induced plasticity in erythrocytes and epithelial cells of hatchlings lizards derived from the eggs of females sampled from four populations and incubated at multiple temperatures. Larger cells were produced in hatchlings from cooler treatments; however, hatchling body size was unaffected by temperature. Therefore, temperature-induced plasticity applies at the cellular, but not organismal, level in A. carolinensis. In addition, reaction norms for cell size differed among populations. There was a latitudinal trend in cell size and in plasticity of cell size among our study populations. The two southernmost populations showed plasticity in cell size, whereas the two northernmost ones did not. We suggest that selection pressure for larger cell size in northern, cooler environments has restricted plasticity in A. carolinensis applied at the cellular level in response to variable incubation environments.     

晋阳肉兔配套系杂交效果研究

对以新西兰白兔、加利福尼亚兔为基础群经过 3个世代纯种选育的父系 (晋 系 ) ,母系(晋 系 )进行配合力测定 ,结果表明 :在 CP1 6.1 3%、CF1 4.57%的中等偏下营养条件下 ,晋 系×晋 系、晋 系×晋 系、晋 系×晋 系 ,42～ 77日龄平均日增重分别为 2 6.62 g、2 6.1 0 g和30 .2 3g,日增重的杂种优势率为 1 4.68%( P<0 .0 1 ) ;料肉比分别为 3.1 6∶ 1、3.37∶ 1和 2 .82∶ 1 ,料肉比的杂种优势率为 1 3.63%( P<0 .0 1 ) ;屠宰率分别为 54.1 2 %、56.2 1 %和 55.79%,屠宰率的杂种优势率为 1 .1 3%( P>0 .0 5)。     

样本量和性比对微卫星分析中群体遗传多样性指标的影响

以4个中国地方鸡品种遗传多样性的微卫星分析数据为例,分析样本量和性比对微卫星分析中群体遗传多样性指标的影响。结果表明:当样本量超过20后,期望杂合度值趋于稳定,样本量与期望杂合度无显著相关,而与平均等位基因数呈正相关,在微卫星分析中性比对群体遗传多样性指标不表现出显著影响;微卫星位点多态性的高低直接影响到检测所需的样本量,在使用平均等位基因数分析群体遗传多样性时,应该充分考虑样本量对检测结果的影响;期望杂合度受样本量变动的影响较小,可作为度量群体遗传多样性的一个最适参数,而且样本量以20～25较为适宜。     

妊娠期背膘厚对母猪产程及繁殖性能的影响

为优化母猪繁殖效率,探究妊娠期不同背膘厚对母猪繁殖性能和分娩产程的影响,本研究以广西某公司2 969头大白母猪和1 787头长白母猪为试验群体,收集2017年1月至2017年10月妊娠期3个阶段(妊娠30、80和107 d)背膘厚与分娩接产记录数据,分析背膘厚与分娩产程、总产仔数、产活仔数和初生窝重等性状的关系。研究结果表明,大白母猪分娩产程时间显著短于长白母猪(P<0.05),大白母猪总产仔数、产活仔数和初生窝重显著优于长白母猪(P<0.05)。在妊娠30 d时,背膘厚在18～20 mm组的大白母猪总产仔数和产活仔数最高,且初生窝重最大;背膘厚在18～20 mm组的长白母猪总产仔数和产活仔数最高。在妊娠80 d时,背膘厚≥20 mm组的大白母猪总产仔数和产活仔数最高,且初生窝重最大、产程最短;背膘厚在16～18 mm组的长白母猪总产仔数和产活仔数最高,且初生窝重较高、母猪产程较短。在妊娠107 d时,背膘厚在14～16 mm组的大白母猪总产仔数和产活仔数最高,且初生窝重最大,但母猪产程与其他组差异不显著(P>0.05);背膘厚≥20 mm组的长白母猪总产仔数和产活仔数最高,且初生窝重较大。妊娠期背膘厚减少1～2 mm的大白母猪,其总产仔数和产活仔数最高,初生窝重较小,产程较长。而背膘厚减少>2 mm的长白母猪,其总产仔数和产活仔数最高,初生窝重较大,产程较短。上述试验结果说明,在母猪妊娠期间,合适的背膘厚可有效提高母猪繁殖性能和母猪分娩期间的福利水平。养殖场可以根据营养配方和猪群品种建立背膘数据库,通过精准饲喂将母猪背膘厚调整至最佳范围,同时合理控制妊娠期背膘变化。     

Genetic implications of a simulation model of litter size in swine based on ovulation rate, potential embryonic viability and uterine capacity: II. Simulated selection

Direct selection for ovulation rate, uterine capacity, litter size and embryo survival and selection for indexes of ovulation rate with each of the remaining traits were simulated for a swine population. The relationships among these traits were determined from a simulation model that assumed that litter size was always less than or equal to both ovulation rate and uterine capacity. Heritabilities of ovulation rate and uterine capacity were assumed to be .25 and .20, respectively, and uncorrelated genetically and phenotypically. No additional genetic variation was assumed. Responses to weak selection pressure were simulated by recurrent updating of phenotypic variances and covariances combined with the heritabilities of ovulation rate and uterine capacity. Two indexes of ovulation rate and uterine capacity each resulted in 37% greater increase in litter size than direct selection for litter size. Indexes of ovulation rate and either litter size or embryo survival increased litter size by 21% more than direct selection for litter size. Selection for ovulation rate, uterine capacity or embryo survival was 6, 35 and 79%, respectively, less effective than direct selection for litter size. Responses to intense selection pressure were determined by direct simulation of genotypes and phenotypes of individuals. The two indexes of ovulation rate and uterine capacity exceeded direct selection for litter size by 39 and 27%. The indexes of ovulation rate and either litter size or embryo survival exceeded direct selection for litter size by 19 and 13%, respectively. Intense selection for ovulation rate or uterine capacity decreased selection response by 26 and 67%, respectively, relative to direct selection for litter size. Intense selection for embryo survival decreased litter size slightly.     

一年生龙胆属植物的繁殖分配及其花大小、数量的权衡关系研究

对青藏高原东缘高寒草甸一年生龙胆属植物的花期繁殖分配及其花大小与数量间权衡关系的研究发现,1)个体越大,繁殖投入越高;2)繁殖分配与个体大小间无固定的相关模式,表明不同物种对相似环境压力的适应对策不同;3)花大小和总花数均随个体增大而增加,花数量的增加要比花大小的增加更加显著;4)在采用偏相关方法控制植物个体大小后,花大小与花数目之间表现出权衡关系,与理论预测一致。