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21.
尼罗罗非鱼(Tilapia nilotica)不同月龄数量性状遗传力估计 总被引：2，自引：1，他引：1
采用不平衡巢式配对的技术,构建尼罗罗非鱼(Tilapia nilotica)半同胞家系30个,估计尼罗罗非鱼数量性状的遗传力。分别对3、4、5月龄的所有家系的家系个体的体重、全长、体长、头长、躯干长、体高、尾柄长、尾柄高及体宽共9个数量性状进行测量,运用半同胞组内相关法估计尼罗罗非鱼3、4、5月龄数量性状的遗传力。结果表明,3月龄尼罗罗非鱼数量性状遗传力的估计值较大为0.73—0.21,4月龄尼罗罗非鱼数量性状遗传力的估计值为0.21—0.06,5月龄尼罗罗非鱼数量性状遗传力的估计值为0.25—0.05,尼罗罗非鱼各性状的遗传力随着月龄增长而减小,遗传力在3月龄最高,4月龄和5月龄较低并接近。本研究结果为进一步开展尼罗罗非鱼选择育种研究奠定基础。 相似文献
22.
Pacific whiteleg shrimp(Litopenaeus vannamei) is an economically relevant shrimp species in many Asian countries. The specific objective of the current research was to assess microsatellite markers in screening the fastgrowth of domesticated L. vannamei stocks to establish a founder population for breeding-selection plans. The postlarvae produced by the reproduction of second generation broodstock were cultured in the same conditions throughout a five months growing period. Ninety juvenile shrimp were selected from the slow-, medium- and the fast-growth groups, and ten microsatellite markers were used to investigate their genetic diversity, and to understand the improvement of a breeding-selection scheme. Ten polymorphic loci(markers)(M1–M10) were produced at ten loci in this sample, among them Primer M8 was the highest polymorphic locus and M7 was the lowest one. A specific locus was found in the fast-growth group using Primer M5. The longest genetic distance(0.481) was determined between the fast- and medium-growth groups and the shortest(0.098) was between the slow- and medium-growth groups; therefore, the largest genetic identity(0.946) was observed between the slowand medium-growth groups and the smallest(0.667) was observed between the medium- and fast-growth groups.The Unweighted Paired Group with Arithmetic Average(UPGMA) dendrogram based on Nei's genetic distances provided two different groups; the first consist of the slow- and medium-growth groups and the second the fastgrowth group. Selection response and realized heritability for growth were 11.55% and 31.26%, respectively.Therefore, this set of microsatellite markers would provide a useful tool in shrimp breeding schemes. 相似文献
23.
马氏珠母贝选系F_2早期选择反应和现实遗传力估计 总被引：9，自引：1，他引：8
对马氏珠母贝基础群体进行持续选择建立选系F2,比较了选系F2与对照群体早期生长差别,并估计了选择反应和现实遗传力。结果表明,在第8、14、21和35天,选系F2的平均壳长显著大于对照群体(P<0.05)。在第8、14、21和35天,选择反应和现实遗传力变化范围分别为0.63～0.89和0.36～0.51。本研究表明利用群体选择可以明显改良马氏珠母贝养殖群体的生长性状。 相似文献
24.
主效基因位点的相对选择效率 总被引：1，自引：0，他引：1
利用单个已识别主效基因位点加微效多基因的混合遗传模型,在二性状育种目标下探讨基因型选择[Direct Selection of Quantitative Trait Loci(QTL),DSQ]的相对选择效率(Relative Selection Efficiency,RSE),并考察主效基因方差贡献、性状遗传力和遗传相关对RSE的影响,以期找出控制RSE实际应用中的主要影响因素,并最大限度地发挥已识别主效QTL位点在育种中的作用。结果表明,只要主效基因位点的信息合理纳入选择方案,即可从选择方案中主效基因位点的应用中获得较大益处;从RSE来看,DSQ可带来额外程度不同的选择进展;几个因素对RSE的影响程度各不相同,使RSE增长或降低模式彼此不同;主效基因位点的加性遗传方差比例、遗传力和遗传相关对RSE均有较大影响。 相似文献
25.
牙鲆是太平洋西岸海水养殖、捕捞和自然增殖的主要鱼类,但是人工养殖病害多、生长慢,针对这一问题,从2003年开始开展了牙鲆选择育种。本文利用筛选和培育的F1、F2代牙鲆家系核心群体,构建了F3代家系52个,在生长到196d时,对家系1 560尾鱼苗全长、体宽、体质量、全长日增量和体重日增量5个生长性状进行测量和计算,获得7 800个数据。采用"加性-显性"线性模型、最小范数二阶无偏估计法(MINQUE)对以上生长性状的边际平均值、加性方差分量、显性方差分量、随机方差分量、狭义遗传力、广义遗传力、亲本加性效应、杂交随机效应等遗传参数进行了评估。结果显示:1202、1206、1226和1211家系以上生长性状的边际平均值同时显著高于其他家系。以上5个生长性状的加性方差分量比率为(0.099±0.01)~(0.24±0.02),显性方差分量比率(0.30±0.02)~(0.31±0.02),随机方差分量比率(0.48±0.02)~(0.61±0.01),5个性状狭义遗传力0.099~0.24,广义遗传力0.38~0.54,以上遗传参数均达极显著性水平(P0.01)。综合比较18个亲本5个性状的加性效应预测值,发现F0917、F0908、F0905、F0915、F09125和KS(韩国牙鲆)亲本在5个性状上都具有极显著的正向效应(P0.01),其他亲本5个性状都不同程度的表现为显著(P0.05)或极显著(P0.01)的负向加性效应。对42个杂交组合显性随机效应进行预测,D(2×6)、D(2×18)、D(3×4)、D(7×12)、D(7×14)和D(8×13)6个杂交组合在5个性状上都表现为极显著(P0.05)正效应,利用这些杂交组合建立家系将促进牙鲆以上5个性状的生长。本文研究结果,为牙鲆优良家系的建立及新品种的培育初步筛选出了性状优良的亲本、杂交组合和家系,同时为牙鲆进一步选择育种提供了理论和技术依据。 相似文献
26.
熊本牡蛎(Crassostrea sikamea)多嵴和无嵴品系子二代生长性状的选择效应 总被引：2，自引：0，他引：2
为了进一步检查熊本牡蛎(Crassostrea sikamea)多嵴品系及无嵴品系的连续选择反应能力,以两个品系子一代上选组为材料,以壳高为指标,按照10%选择强度,开展了两个品系子二代混合上选研究,评估了两个品系子二代选择反应、现实遗传力,计算了两个品系的遗传改进量。结果表明:两个品系仍具有较高的现实遗传力,多嵴品系遗传参数均大于无嵴品系,表现出较好的遗传改良效果。多嵴和无嵴品系幼虫期的选择反应分别为0.47、0.34,稚贝期为0.65、0.40,养成期为0.82、0.56;幼虫期的现实遗传力分别为0.27、0.19,稚贝期为0.37、0.23,养成期为0.47、0.32;幼虫期的遗传改进量分别为4.83%、3.61%,稚贝期为7.55%、5.76%,养成期为9.95%、6.47%。经过一周年的养成,多嵴品系壳高显著大于无嵴品系,两个品系现实遗传力分别为0.50、0.35,遗传改进量分别为10.13%、6.61%。由此可见,多嵴品系具有较快的生长速度,遗传改良潜力较大。本研究为熊本牡蛎遗传改良和新品系培育奠定了坚实的基础。 相似文献
27.
星斑川鲽家系建立及遗传效应分析 总被引：2，自引：0，他引：2
星斑川鲽是优良的鲆鲽鱼类种质之一,在鲆鲽鱼类养殖产业中具有重要的地位。本研究初次收集了分布于山东半岛的4个养殖群体(日照、胶南、威海和蓬莱)的350尾亲鱼,分别测量了100尾雌雄亲鱼的体长和体质量,拟合了雌雄性亲鱼体质量和体长幂函数关系,分别为:y=0.034 2x2.843 6 (R2=0.565)和y=0.075 9x2.533 4(R2=0.753 8)。利用其中成熟的55尾雄鱼和46尾雌鱼进行人工繁殖,雌鱼平均产卵次数为4.39次、雄鱼产精次数为2.36次。其中25个杂交组合繁殖成功,建立了29个半同胞和全同胞家系。在家系生长到150 d时,对1 640尾鱼苗体质量、全长、体长和体宽4个性状进行测量。利用最小范数二次无偏估计法(MINQUE)对以上性状的方差组分进行估计,利用"加－显性"模型对生长性状遗传力进行估计,采用线性无偏预测法(Linear Unbiased Prediction,LUP)预测亲本的加性和显性遗传效应。结果显示:4个性状的遗传相关系数为0.809~0.999(P<0.01)。体质量、全长、体长和体宽4个性状的加性、显性方差分量都达到极显著水平(P<0.01),狭义遗传率为0.311~0.444(P<0.01),广义遗传率为0.377~0.525(P<0.01)。加性遗传效应预测显示:31个亲本中的6个在4个性状上同时具有极显著的正向效应(P<0.01),10个亲本具有极显著(P<0.01)或显著(P<0.05)的负向效应。显性随机效应预测显示:25个杂交组合中6个具极显著正向效应(P<0.01),8个具有极显著负向效应(P<0.01)。研究结果首次为星斑川鲽家系建立和优良苗种培育筛选出了优良的亲本和杂交组合,同时为星斑川鲽的选择育种提供了丰富的遗传指标。 相似文献
28.
Genetic parameter estimates for growth traits at early stage of Pacific abalone,Haliotis discus hannai Ino 总被引：2，自引：0，他引：2
Heritability and genetic and phenotypic correlations were estimated for juvenile growth traits of Pacific abalone Haliotis discus hannai Ino.The estimates were calculated from shell length and shell width measurements on progeny resulting from 12 half-sib families and 36 full-sib families obtained using artificial fertilization of mating three females to each male.The measurements were taken at 10,20 and 30 d after fertilization.It was found that heritability estimates based on sire component ranged from 0.23 to 0.36 for shell length and 0.21 to 0.32 for shell width.Heritability estimates from dam component were larger than those from sire component at three ages,indicating presence of maternal effects,non-additive genetic effects and common environmental effects.Phenotypic correlations were significant at three ages(P < 0.05),with values of 0.92,0.93 and 0.92,respectively.Genetic correlations from the paternal half-sib correlation analysis were highly positive at three ages,with values of 0.50,0.78 and 0.81,respectively.The results suggest that selective breeding is an effective approach to improving growth traits of Pacific abalone stocks. 相似文献
29.
Response to selection for fast growth in the second generation of Pacific oyster (Crassostrea gigas) 总被引：1，自引：0，他引：1
Mass selection for fast growth was conducted in three Pacific oyster (Crassostrea gigas) stocks from China, Japan and Korea using previously established lines (CS1, JS1, and KS1). To determine whether continuous progress can be achieved by selection for growth, the progeny of three second-generation Pacific oyster lines was selected for shell height and evaluated via a 400-day farming experiment. When harvested at the end of the experiment, the selected crosses of CS2, JS2, and KS2 lines grew by 9.2%, 10.2% and 9.6% larger than the control crosses, respectively. During grow-out stage, the genetic gain of three selected lines was (10.2 ± 1.4)%, (10.4 ± 0.3)%, and (8.4 ± 1.6)%, respectively; and the corresponding realized heritability was 0.457 ± 0.143, 0.312 ± 0.071 and 0.332 ± 0.009, respectively. These results indicated that the selection for fast growth achieved steady progress in the second generation of oyster. Our work provides supportive evidence for the continuity of the Pacific oyster selective breeding program. 相似文献
30.
Estimates of genetic and phenotypic parameters for weight and length in Paralichthys olivaceus (Temminck et Schlegel) 总被引：1，自引：0，他引：1
The complete diallel cross design was employed to estimate the genetic parameters of the growth of Japanese flounder (Paralichthys olivaceus). A total of 60 full-sib families were cultivated and two growth-related traits, body weight (BW) and body length (BL), were examined at average 2, 3 and 8 months of age respectively, with 1 800 individuals measured in each age group (30 per family). Based on the additive-dominance-maternal-effect genetic analysis model, the restricted maximum likelihood approach was used to estimate various (co)variance components. The results showed that narrow-sense heritability estimates of BW and BL were respectively:0.29±0.01 and 0.22±0.02 at 2 months of age, 0.32±0.02 and 0.30±0.04 at 3 months of age, 0.48±0.04 and 0.40±0.05 at 8 months of age; broad-sense heritability estimates were respectively:0.44±0.02 and 0.54±0.04 at 2 months of age, 0.35±0.01 and 0.36±0.03 at 3 months of age, 0.49±0.03 and 0.45±0.04. All heritabilities were statistically significant (P <0.05). Additive genetic correlations between BW and BL at 2, 3 and 8 months of age were consistently positive and highly significant (P <0.01):0.93±0.02, 0.95±0.03 and 0.92±0.03 respectively. Maternal effect was significant (P <0.05) only at 2 months of age, and was not detected at 3 and 8 months of age. According to the heritability estimates, the mass selection strategy should be efficient for the breeding of Japanese flounder. 相似文献