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一、基因型与适应性从品种的适应性来看,同一基因型的蚕品种,在不同的环境中,各种性状有不同程度的反应。这种同一基因型在不同环境下表现型所表现的变化范围,在遗传学上叫做反应规范。不同蚕品种各种性状的反应规范是不同的,亦就是说基因型决定品种的适应性。因此,任何蚕品种在推广之前,都必须经过不同季节的区域性多点鉴定,以查明某品种在不同地区、不同季节的适应性,才能决定该品种的推广季节和推广范围。作者认为适应该地区季节饲养的蚕品种,就可称为该地区该季节的优良品种。 相似文献
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为了解不同苜蓿（Medicago sativaL.）品种在宁夏南部山区的丰产性、稳产性，以及试点的代表性和区分力，本研究利用方差分析、GGE双标图模型对区域3个不同试点的6个苜蓿品种的产量进行分析。结果表明：苜蓿产量最高的试验区是原州区彭堡镇彭堡三队，最低的是隆德县关庄乡前庄村，前者比后者高43.7%；产量最高的品种是‘甘农7号’，最低的是‘阿尔冈金’，前者比后者高44.9%；联合方差分析显示，基因型与环境互作（G×E）、环境（E）、基因型（G）对品种产量影响显著（P<0.05），其中G×E是引起苜蓿产量差异的最主要原因，它引起的变异是E的1.19倍，是G的1.58倍。利用GGE双标图模型分析可知，高产稳产的品种是‘三得利’、‘苜蓿王’；3个不同区域可划分为2个生态区，原州区头营镇徐河村和原州区彭堡镇彭堡三队为1个，隆德县关庄乡前庄村为1个；综合代表性和区分力，较理想的试点为头营镇徐河村。 相似文献
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为了进一步了解基因型、环境及其互作对糜子主要农艺性状的影响,运用联合方差和AMMI模型对6个糜子新品种(粳性)在11个不同环境试点的生育期、株高、主茎节数、主穗长、穗粒重、千粒重和产量等7个主要农艺性状的表现及其品种稳定性与适应性进行了研究。结果表明,糜子主要农艺性状在不同基因型以及环境之间存在极显著差异,其中基因型对主茎节数、环境对株高、基因型与环境互作对穗粒重的影响较大。各品种7个农艺性状指标的变异系数中,最大的是产量,达42.72%,其次是穗粒重和株高,分别为37.90%和26.74%,变异系数最小的是生育期,为14.89%。各试点中产量最高的是甘9133-1-3-4-1,品种稳定性最好的是榆糜3号(CK)。宁夏彭阳和陕西延安试点产量较高,变异程度较小,对品种鉴别力较好。 相似文献
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绵羊MyoG基因外显子的单核苷酸多态性群体遗传学分析 总被引：1，自引：0，他引：1
采用PCR—SSCP技术分析了肌细胞生成素（MyoG）基因外显子1、2在蒙古羊、无角陶赛特羊、德国肉用美利奴羊和白萨福克羊这4个绵羊品种的多态性。结果表明在在外显子1（exonⅠ）所扩增的片段中存在3种基因型（AA型、AB型和BB型），在外显子2（exonⅡ）所扩增的片段中不存在多态性。对于exonⅠ扩增片段，4个绵羊品种均检测到AA和AB基因型；BB基因型只在蒙古羊、陶赛特羊和白萨福克羊中检测到。在4个绵羊品种中，蒙古羊的AA基因型频率最高，而其它3个品种羊是AB基因型频率高；A等位基因频率明显高于B等位基因频率。exonⅠ的多态性片段测序分析表明：MyoG基因第305处发生了单碱基突变（T→C），并导致了所编码氨基酸由半胱氨酸变为精氨酸。 相似文献
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8个燕麦品种在甘肃的产量稳定性及试点代表性研究 总被引：2，自引：0，他引：2
为了客观、准确地评价燕麦品种的稳定性和适应性,本研究采用GGE双标图对2012年甘肃省燕麦（Avena sativa）种植区域5个试点中的8个燕麦品种试验数据进行分析。结果表明：在燕麦种植区的大环境下,品种与环境互作效应对产量变异的影响约为品种效应的4.02倍。‘陇燕2号’和‘陇燕3号’属于高产、稳产性好的品种;‘青引1号’具有特殊适应性,在局部地区有推广价值。5个燕麦区试点可划分为2个不同的类型区,其中在甘肃中部半干旱地区表现最好的品种是‘陇燕1号’,在甘肃高寒阴湿区表现最好的品种是‘陇燕3号’。从环境代表性和对品种鉴别能力两方面分析,5个试点中代表性最好的是通渭,鉴别力最好的是天祝。 相似文献
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由于受积温、光照时间、降雨量等因素影响,不同青贮玉米品种在不同地区种植产量差异很大,通过对龙巡32、中原单32、龙辐单208、中北410、白鹤和高油115在不同区域的种植,试验表明,龙巡32和中原单32适合在第二、三、四积温带推广种植;龙辐单208适合在第一积温带和第二、三积温带东部地区推广种植:白鹤适合在哈尔滨周边地区及第二、三积温带东部地区推广种植;高油115仅适合在第一积温带推广种植;中北410适合在第一、二积温带东部地区推广种植。 相似文献
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小尾寒羊高繁殖力候选基因RARG的研究 总被引：8，自引：0，他引：8
以视黄酸受体γ（retinoic acid receptor-gamma，RARG）基因为候选基因，采用PCR—SSCP技术分析了RARG基因在高繁殖力绵羊品种（小尾寒羊、湖羊）以及低繁殖力绵羊品种（特克塞尔、多赛特、萨福克）中的单核苷酸多态性，同时研究这个基因对小尾寒羊高繁殖力的影响。结果表明：RARG基因引物1扩增片段在5个绵羊品种中存在PCR—SSCP多态性，AA基因型只出现在湖羊中，AB和BB基因型均出现在5个绵羊品种中；BB基因型小尾寒羊平均产羔数比AB基因型多0．41只，但差异不显著（P〉0．05）。RARG基因引物2扩增片段在5个绵羊品种中存在PCR—SSCP多态性，CC和CD基因型均出现在5个绵羊品种中，5个绵羊品种中都没有检测到DD基因型；CC基因型小尾寒羊平均产羔数比CD基因型多0．55只（P〈0．05）。 相似文献
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基于AMMI模型的二化地区部分一化性柞蚕品种产茧量性状的稳定性分析 总被引：1，自引：0，他引：1
品种区域试验是柞蚕品种选育过程中评定参试品种和推广优良品种的一个重要环节,为探索二化地区一化性柞蚕品种的丰产和稳产性能,采用主效可加互作可乘模型(additive main effects and multiplicative interaction,AMMI)对辽四、辽8、四青等9个一化性柞蚕品种产茧量进行一点多年的比较试验.结果表明,基因型平方和占总平方和的55.85％,环境平方和占总平方和的4.34％,基因型与环境互作的平方和占总平方和的17.98％,上述一化性柞蚕品种在3个不同年份间的产茧量存在极显著的基因型、环境以及基因型与环境互作效应.其中稳产性最好的柞蚕品种为四青、883,丰产性最好的品种为辽四和辽8,稳产性和丰产性均较好的品种为辽8和松黄.883、鲁黄、四青、F-F、辽四与2014和2015年的环境有正的互作效应,而与2013年的环境有负的互作效应;932、吉黄、松黄、辽8与2013年的环境有正的互作效应,而与2014和2015年的环境有负的互作效应.分析表明,品种与环境之间存在较强的互作效应,辽8是丰产、稳产、适应性强的一化性柞蚕品种,辽四是丰产、适应性强的一化性柞蚕品种. 相似文献
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Franklin L. Pellegrini DVM 《Journal of Equine Veterinary Science》2005,25(3):113-117
A necropsy was performed on over 500 horses from a Texas abattoir for the presence of gastric and colonic ulceration. A first group of 365 horses from a variety of sources was examined, and 55% were found to have gastric ulcers, while 44% exhibited colonic ulcers. A second group of 180 performance horses was also examined, and 87% were shown to have gastric ulcers, while 63% exhibited colonic ulcers. The second study included a correlated guaiac-based fecal occult blood test (gFOBT), which was shown to have high specificity but a fairly low sensitivity resulting in several false negatives. 相似文献
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为了探讨收割茬次对紫花苜蓿产量及营养价值的影响,选取了3个紫花苜蓿品种(新牧1号、新牧2号、当地苜蓿),分别年收割三茬,并测定其单位面积鲜重、干重,测定常规营养成分。结果表明,新牧2号和当地苜蓿鲜草产量和干草产量显著高于新牧1号紫花苜蓿(P<0.05)。新牧1号、新牧2号和当地紫花苜蓿在粗蛋白、粗脂肪、粗纤维、粗灰分、无氮浸出物、钙含量方面差异不显著(P>0.05)。第一茬的营养价值优于第二茬和第三茬。总体来看,新牧2号紫花苜蓿产量和营养价值优于新牧1号紫花苜蓿。 相似文献
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Relationships among bull libido, serum hormone concentrations and semen characteristics were studied using 18 Holstein bulls that were 4 to 5 yr old. The hormones studied included testosterone, estradiol (E2), prolactin (PRL), LH and cortisol. Two ejaculates were collected three times per week from each bull during a 5-wk trial. During the last week of the trial, on a day semen was not collected, blood was collected from indwelling catheters every 15 min for 6 h to determine the hormonal profiles of each bull. On the following day, blood was sampled every 10 min before and after the time of semen collection. Libido factors were quantified, and semen volumes and sperm concentrations were recorded. The libido factors included reaction time to first service, latency time between the first and second semen collections, and duration of time the bull mounted the teaser prior to the first (TM1) and second (TM2) semen collection. Average reaction and latency times were correlated (r = .524; P = .026), as were TM1 and TM2 (r = .597; P = .015). Latency times were correlated with average TM2 (r = .669; P = .003). Average PRL concentrations were correlated with average latency times (r = .467; P = .05). Low libido bulls tended to have higher E2:testosterone ratios than did high libido bulls. Both PRL and cortisol concentrations increased at semen collection. 相似文献
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Persistence of chicken herpesvirus and retroviral chimeric molecules upon in vivo passage 总被引：2，自引：0，他引：2
Mareks disease virus (MDV), a herpesvirus, and avian leucosis virus subgroup J (ALV-J), a retrovirus, were used for experimental coinfection of chickens. Chimeric molecules having sequences of both viruses were detected by the hotspot-combined polymerase chain reaction (HS-cPCR) system. The detection of chimeric molecules provided evidence for avian retroviral inserts in the herpesvirus genome. The persistence of chimeric molecules on in vivo passage served to indicate the infectivity of the recombinant virus. The evaluation of formation and persistence of the chimeric molecules was performed in two trials involving three in vivo passages. The chimeric molecules were identified according to the primer sets, their product length, and pattern. The persistence of chimeric molecules on in vivo passages served as an indication of their ability to replicate in and infect chickens. In the first experimental passage, MDV and ALV-J prototype strains, MD11 and HC-1, were intraperitoneally (i.p.) injected into 1-day-old chicks. The second trial included two passages. Passage II chicks were injected i.p. and passage III chickens were in contact with the chickens of passage II. For passage II, enriched white blood cells from blood samples of chickens from the first trial that had chimeric molecules were injected i.p. into 1-day-old chicks. For passage III, uninfected chicks were included together with the infected chicks. Synthesis evidence for the various species of chimeric molecules was assessed in the tissues of birds of the second trial. DNA was extracted from blood and feathers and analyzed by the hotspot-combined PCR and by pulsed field gel electrophoresis. To overcome the limits of detection, three amplification assays followed by hybridization of the products to specific viral probes were conducted. A variety of chimeric molecules were detected in low concentrations. Five species of chimeric molecules were characterized in blood, tumors, and feathers. Chimeric molecules were detected in 18 of 36 dually infected birds from the first trial and in 14 of 21 dually infected birds from the second trial. The findings show that, in four out of seven groups of the second trial, the chimeric molecule species persisted on passage. 相似文献
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Jorge Hidalgo Daniela Lourenco Shogo Tsuruta Yutaka Masuda Vivian Breen Rachel Hawken Matias Bermann Ignacy Misztal 《Journal of animal science》2021,99(9)
Accuracy of genomic predictions is an important component of the selection response. The objectives of this research were: 1) to investigate trends for prediction accuracies over time in a broiler population of accumulated phenotypes, genotypes, and pedigrees and 2) to test if data from distant generations are useful to maintain prediction accuracies in selection candidates. The data contained 820K phenotypes for a growth trait (GT), 200K for two feed efficiency traits (FE1 and FE2), and 42K for a carcass yield trait (CY). The pedigree included 1,252,619 birds hatched over 7 years, of which 154,318 from the last 4 years were genotyped. Training populations were constructed adding 1 year of data sequentially, persistency of accuracy over time was evaluated using predictions from birds hatched in the three generations following or in the years after the training populations. In the first generation, before genotypes became available for the training populations (first 3 years of data), accuracies remained almost stable with successive additions of phenotypes and pedigree to the accumulated dataset. The inclusion of 1 year of genotypes in addition to 4 years of phenotypes and pedigree in the training population led to increases in accuracy of 54% for GT, 76% for FE1, 110% for CY, and 38% for FE2; on average, 74% of the increase was due to genomics. Prediction accuracies declined faster without than with genomic information in the training populations. When genotypes were unavailable, the average decline in prediction accuracy across traits was 41% from the first to the second generation of validation, and 51% from the second to the third generation of validation. When genotypes were available, the average decline across traits was 14% from the first to the second generation of validation, and 3% from the second to the third generation of validation. Prediction accuracies in the last three generations were the same when the training population included 5 or 2 years of data, and a decrease of ~7% was observed when the training population included only 1 year of data. Training sets including genomic information provided an increase in accuracy and persistence of genomic predictions compared with training sets without genomic data. The two most recent years of pedigree, phenotypic, and genomic data were sufficient to maintain prediction accuracies in selection candidates. Similar conclusions were obtained using validation populations per year. 相似文献
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旨在探究刈割茬次对杂交构树青贮发酵品质和常规养分价值的影响。选取品种、播种期、生境和管理相同,年刈割3茬的杂交构树作为研究对象,于播种后14个月收获第1茬,此后每间隔35 d左右收获第2、3茬,收获后即进行窖贮。发酵完成后,对第1、2、3茬杂交构树青贮的发酵品质和营养价值进行评价。结果:在青贮发酵品质上,随着杂交构树收获茬次的增加,青贮后的pH值、丁酸含量、V-Score分值显著降低(P<0.05),相应乳酸、乙酸含量则逐渐增加;各茬次氨态氮/总氮的比值差异显著(P<0.05),由低到高依次为第3、1、2茬。常规养分中,各茬次青贮的粗蛋白、可溶性蛋白、非蛋白氮、水溶性碳水化合物含量差异显著(P<0.05),由高到低依次为第3、1、2茬;各茬次中性洗涤纤维、酸性洗涤纤维含量差异显著(P<0.05),由低到高依次为第3、1、2茬;第2茬的酸性洗涤木质素含量最高,第3茬的中性洗涤不溶氮和酸性洗涤不溶氮含量最低;各茬次干物质、淀粉含量差异显著(P<0.05),呈现为第1茬>第3茬>第2茬的趋势,而脂肪含量相反,表现为第1茬<第3茬<第2茬;粗灰分含量随茬次的增加显著降低(P<0.05)。参考NRC(2001)奶牛营养需要提供的方程计算并对比各茬次的总可消化养分(TDN)和各项能值,结果均为第3茬>第1茬>第2茬,且各茬次间差异显著(P<0.05)。研究表明,杂交构树青贮品质由优到劣依次为第3茬、第2茬、第1茬;常规养分价值由高到低依次为第3茬、第1茬、第2茬。 相似文献
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Ovulation rate was measured by laparoscopy at two consecutive cycles on 366 ewes 2 yr old and over and 85 yearling ewes of five lines of Targhees from the base base population; 53 yearling linecross ewes were also included. The lines were two unselected controls (HCl and DC), two selected for 21 yr for increased 120-d weight (HW and DH) and one selected for 19 yr for multiple births (T). Ewes were synchronized in late July or early August at the start of the normal breeding season with intravaginal pessaries impregnated with 60 mg methylacetoxyprogesterone and examined at first and second estrus. Ovulation had occurred in both cycles in 327 (89%) and 177 (85%) of the mature and yearling ewes, respectively. Overall mean numbers of corpora lutea at first and second estrus were 1.42 and 1.63, respectively for ewes 2 yr and over and 1.20 and 1.44 for yearlings, indicating an effect of synchronizing treatment, season, flushing, or a combination of these. Among mature ewes, ovulation rate was higher (P less than .05) in DH (+.20), HW (+.19) and T (+.16) than in controls at first estrus, and in HW (+.29) and T (+.21) but not DH (-.04) at second estrus. Among yearlings, differences were significant only at second estrus (HW, +.40; T, +.35) and again not for DH (+.08). The failure of line DH to increase in ovulation rate from first to second estrus as did other lines was transmitted to linecross progeny. Body weight within line affected ovulation rate significantly, with a greater effect at second estrus, in both age groups. Adjustment for body weight removed the difference between HW and controls but not between T and controls. Repeatability of corpora lutea count was .27 and .25 for mature and yearling ewes, respectively. 相似文献
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B Zumbach S Tsuruta I Misztal K J Peters 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2008,125(3):160-167
Breeding value prediction for dairy goats in Germany is still based on herd mate comparison within breeding society. The objective of this study was to estimate genetic parameters for milk yield based on a test day model. For the analysis 35,308, 30,551 and 23,640 test day records from lactations 1, 2 and 3 from 5079, 4118 and 3132 animals, respectively, were used. The data between 1987 and 2003 were obtained from six German breeding societies. The multiple trait (lactations 1, 2 and 3) repeatability model (RPT) included the fixed effects of breeding society-breed-herd-year, litter size, lambing season, and days in milk of third-order Legendre polynomials nested within herd-year, and the random effects of animal additive and permanent environment. The three-trait random regression model (RR) also included the random regressions based on second-order Legendre polynomials for animal additive and permanent environmental effects. Heritability estimates in RPT were 0.27 +/- 0.02, 0.20 +/- 0.02 and 0.37 +/- 0.02 for the first, second and third lactation, respectively. The genetic correlation between the first and second lactation was 0.69, between the second and third lactation 0.79, and between the first and third lactation 0.45. Heritability estimates from the RR in the first and second lactations decreased from the beginning to the end of the lactation, with average values of 0.28 and 0.27, respectively. Estimates in the third lactation showed a maximum in the middle of lactation, averaging 0.37. Genetic correlations between the first and second lactation averaged 0.64, between the second and third lactation 0.72, and between the first and third lactation 0.46. Despite the small data set and restricted relationship structure the estimates were reasonable with the exception of estimates from the third lactation, which seemed inflated. RR could be used for genetic evaluation of dairy goats in Germany. 相似文献
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Conception rates in farm mink (Neovison vison) in relation to first mating date,age and color variety 
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下载免费PDF全文 The aim of the study was to analyze the effects of the first mating date, age and color variety on the conception rates in farm mink. We analyzed female mink reproductive performance in 492 Sapphire and 463 Standard Black females over 3 or 4 years. The analysis included the number of inefficient matings, the interval between the first inefficient mating and the efficient mating (copulation) and the conception rates. The results show a significant effect of female's age and color variety on the conception rates. The youngest, yearling females of either color needed a higher number of matings per conception, as compared to older, 2‐ and 3‐year‐old females. Black females demonstrated a higher number of inefficient matings (1.066), as compared with Sapphires (0.730). Yearling females were most often mated from 1 to 10 March, and older females from 11 to 20 March. Older females achieved better conception rates than the yearlings. Dates between 11 and 25 March proved to be the optimum for the first mating, since the highest conception rates were observed if the females had mated during this period. 相似文献
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Hypothermia is a major cause of mortality in neonatal piglets. However, there are considerable individual differences in the successful recovery from postnatal hypothermia in the common farrowing environment, and so far the causes and interactions of causes have not been studied in detail. Using 635 crossbred neonatal piglets, the aim of this study was to identify the links among different physiological and behavioral measures and their connections to the ability of piglets to overcome initial postnatal hypothermia, with rectal temperature at 2 h as the response variable. The data included birth weight, hypoxia at birth (viability score and lactate in umbilical cord blood), latency to first udder contact and first suckle, scans of individual piglet position during the first 2 h after birth, and rectal temperature at birth and 2 h postpartum. A graphical chain model was used to analyze data. The statistical variables were divided into blocks according to level (design and litter) and chronological order (prenatal, birth, perinatal, and thermoregulatory success at 2 h) before applying the graphical model to the data. Bayesian information criteria (BIC) was used for model selection. The BIC relates to maximum likelihood, but introduces an additional penalty term for the number of variables. The strength of an association between 2 variables is reported as the increase in BIC (BICinc) due to removing the link. Results indicate that at 2 h, 22.1% of the piglets had a rectal temperature below 37 °C. Out of the 16 variables included in the model, only 3 had direct links to the response variable of rectal temperature at 2 h. There was a positive relationship between rectal temperature at 2 h and birth weight (BICinc=26), and between being observed more often by the udder as opposed to alone during both the first (BICinc=8) and second hours (BICinc=19) after birth. Lighter piglets and piglets that had experienced hypoxia took longer to achieve first suckle, which in turn affected where the piglet positioned itself during the first and second hours after birth. Variables related to the birth process had no direct connection to thermoregulatory success, but were additive in the explanation of piglet behavior. The rectal temperature of individual piglets at 2 h depends largely on piglet birth weight and on piglet position in relation to sow and littermates. Birth weight is the most important single factor in successful recovery from postnatal hypothermia. 相似文献