菁松人工饲料选拔系一代杂交种农村饲养报告

现行推广蚕品种对人工饲料的摄食性选择,一方面要求在提高原种对饲料摄食性的同时基本保持原种的基本性状,另一方面也要满足一代杂交种的基本性能与对照种无明显差异。为了检验原种的饲料摄食性选择是否影响一代杂交种的性状表现,本试验分别以菁松选择系(菁松R)和对照系(菁松)与皓月组配生产的一代杂交种"菁松R×皓月"和对照"菁松×皓月"为材料,在江苏盐城大丰区和云南大姚县做了试验比较,结果显示:选育系的产量和生命力均与对照系相仿,没有出现饲料摄食性选择引起杂交种性能下降的现象。     

若干家蚕品种的复壮及比较试验

对浙江省夏秋蚕品种薪杭,白云,丰1和54A等进行了充血复壮改良,基本稳定后的复壮系与现行生产系进行了生产性能的比较试验。结果表明复壮系在各项性状都有一定的提高,其中龄期经过,各品种的复壮系与生产系之间差别不大,只有薪杭丙和白云丙稍有延长。全茧量和茧层量基本上复壮系都比生产系有所提高。生命率差异比较大,奠中薪杭的复壮系低下生产系,差异达到显著水平,白云复壮系略微低于白云甲,但高于白云乙,丰1的复壮系与生产系无明显差异,54A则是复壮系高于生产系。良卵数除薪杭丙比薪杭甲略低外,其他品种的复壮系都比生产系显著提高,有的甚至达到极显著水平。说明复壮系在生产性能上有较大的改良,有一定的推广应用价值。     

日本蚕品种改良和蚕种业法规（续11）

1906年外山博士提出一代杂交种的优越性后，一代杂交种在1913年就得到普及推广，到1923年左右，全国推广一代杂交种已达90％，到1925年后几乎全部是杂交种，这是蚕茧生产一大变革。但是在蚕种生产中出现原种难养，产卵少，杂交种计划完不成现象。因此，在1918年采用杂交原种，最初用于制造三元杂交种，接着1919年又进一步试验更有利的四元杂交种。当时多元杂交种的研究主要是将中系品种和日系品种中的化性不同的品种如二化×一化等组合配制成杂交原种。     

蜜蜂的近亲交配(五)——蜜蜂近交系保存

正蜜蜂育种工作中,建立近交系的目的是利用不同近交系组配多种杂交组合,生产杂交种,然后用于生产,杂种一代往往表现出明显的杂种优势,在生产中容易获得高产。但是该杂交种并不是一个新品种,因杂交种的优良性状并不能稳定遗传给下一代,在杂种二代中就会出现性状分离。     

桑树杂交优势的利用研究——C_6×C_5杂交组合的选育

本研究从组配的多对桑树杂交组合中,选育出C_6×C_5组合,该组合的一代杂交种苗木,经过连续多年的观察和比较试验,杂交优势稳定。主要生物学性状和经济性状超过对照沙2×伦109,并克服了沙2×伦109一代杂交苗木在重庆地区易受冻害的弱点。该组合是适合四川和重庆蚕桑生产使用的一对强优势桑树杂交组合。     

家蚕品种9·芙×7·湘粤桂湘三地品系的性状比较

9·芙×7·湘是我国目前推广量最大的家蚕品种之一。为了比较该品种不同地方品系的生产性能与繁育性能的差异性,分别引进了家蚕9·芙×7·湘粤系和桂系原原母种,与湖南省蚕桑科学研究所繁育继代的生产品系展开对比试验。结果表明,湘系原原母种在产附,孵化,经济性状,强健性方面综合性状优良,其一代杂交种的虫蛹统一生命力最高、一茧丝长最长、净度最优。粤系一代杂交种在解舒丝长、解舒率、出丝率等丝质成绩表现突出。     

利用茧形判定家蚕普通种杂交率调查

家蚕一代杂交种 ,通常是以日系×华系(正反 )杂交组合形式 (二元交 )繁育制成的 ,由于近年大量生产三元交、四元交杂交种 ,故又称家蚕普通种。其杂交优势 ,如茧形较大、茧丝长长、茧层率高、出丝率高等茧丝质经济性状方面的特点和抗逆性强、强健好养的生物学特点 ,能充分表达 ,从而为丝绸工业提供优质的原料茧。以华系为母体的普通斑纹的杂交种 ,即华系 (素蚕 )×日系 (普斑 )杂交组合形式 ,其杂交率可在饲育至 4龄第 3天后 ,通过斑纹的差异进行调查。但是 ,以日系 (普斑)×华系 (素蚕 )、华系 (素蚕 )×日系(素蚕 ) (正反交 )等组合形式的…     

利用mln基因提高蚕种杂交率的研究(初报)

<正> 农村大面积养蚕中,一般饲养中国系统品种与日本系统品种杂交而成的一代杂交种。制造杂交种的原种蚕蛾一般很难分辩是中系还是日系。因此在制种时从蚕蛾上很难分清是否是纯对。纯对多,导致杂交不彻底,对蚕种质量和养蚕生产影响较大,如能育成优质强健黑蛾品种使蛾色为灰黑色,与普通品种蚕蛾白色有明显差异,在对交中黑白分     

两广二号新品系一代杂交种繁育试验

为进一步了解经复壮改良后形成的两广二号新品系的繁育性能,对两广二号新品系进行一代杂交种繁育试验,比较新品系的发育经过、种茧调查成绩及繁育成绩.结果显示,两广二号新品系原蚕发育比较快,日系7532×湘晖(新)的龄期经过比7532×湘晖缩短2 h,中系932×芙蓉(新)的龄期经过比932×芙蓉缩短3 h.两广二号新品系原蚕...     

应用家蚕暗化型基因提高杂交率

家蚕一代杂交种的杂交率是困扰蚕种质量的重要问题之一。为保证蚕种质量,国家制定了家蚕一代杂交种的强制性标准,即家蚕一代杂交种的杂交率不得低于95％。每年国内常有因杂交率达不到标准而成批淘汰的蚕种,常因杂交率低造成减产、蚕农索赔事件时有发生。现生产用蚕品种均为白蛾,区别不明显,蚕种生产环节多,难以做到杂交彻底。为解决这一难题,蚕种生产一直沿用传统的蛾体喷染不同颜色的操作技术,识别杂交中的纯对淘汰,以确保一代杂交种的杂交率。使用该方法虽有效果,但费工费时,造成蛾体污染,缩短雄蛾寿命,降低蛾活力,增加不良卵率,且操作不便。     

家蚕春用品种菁松·皓月的复壮系比较试验

对春用蚕品种菁松、皓月的复壮系与现行生产上应用的生产系进行了生产性能的比较试验。结果表明,与各品系对应的生产系相比,复壮系的龄期经过稍有缩短,生命率略高,全茧量、茧层量、种茧选留率、良卵量与良卵率均有较大提高,达到显著水平以上,说明复壮后的菁松、皓月从孵化到制种各阶段的生产性能优于现行生产应用的生产系,有推广应用价值。     

鸡新城疫不同弱毒株毒力及免疫原性研究

本研究比较了9株鸡新城疫不同弱毒株的毒力和免疫原性。结果显示,新城疫弱毒耐热B株、V4株、Ulster 2C株基本不致死鸡胚,ICPI为0,MDT/MLD大于150h;Hitchner B1株及F株7/10鸡胚致死,死胚胎儿有明显充血、出血病痕,120h活胚明显萎缩,ICPI为0.213～0.238,MDT约为120h;La Sota株、Clone30株、N79株及VG/GA株120h内鸡胚全部死亡,死胚胎儿有明显充血、出血病痕,ICPI为0.3～0.4,MDT约为103～109h。9株NDV的IVPI均为0对鸡只不致病,但免疫原性有所不同,NDVB株免疫原性较好,全部保护,NDVF株最弱。     

Muscle protein turnover in chickens selected for increased growth rate, food consumption or efficiency of food utilisation: effects of genotype and relationship to plasma IGF-I and growth hormone

1. Rates of muscle protein turnover, growth, and food consumption were determined in 4 lines of chickens selected for either weight gain (line W), food consumption (line F), efficiency of food conversion (line E), or at random (line C) and in two Australian commercial broiler strains (S and H). These measures were related to body composition and the circulating concentrations of plasma growth hormone (GH) and IGF-I. 2. N tau-methylhistidine excretion was 10-14% higher in line F and 7-13% lower in line E compared to line C, showing divergence in the rate of muscle protein breakdown with selection. 3. There were no differences between the 4 experimental lines (W, F, E and C) in muscle protein fractional synthesis rates, whether calculated from N tau-methylhistidine excretion or measured directly by 3H-phenylalanine incorporation. 4. No consistent differences were found between lines in circulating concentrations of either GH or IGF-I but plasma IGF-I concentrations were positively correlated over all lines with protein accretion rates. There was a strong inverse correlation over all lines between the rates of protein degradation and FCR. 5. The correlated responses in protein degradation rates are consistent with the notion of a positive genetic association between the overall efficiency of food utilisation for growth and the efficiency of protein metabolism.     

高加索三叶草、白三叶及其F1代株系种子特征的比较

为了选育优良的三叶草品种,对高加索三叶草、白三叶及其10个F1代株系种子的颜色、大小、千粒重、发芽率及出苗率进行了比较分析。结果表明,供试材料种子各指标间均存在显著差异（P<0.05）,10个F1代株系种子特征都与母本高加索三叶草相似,与父本白三叶的差异均较大。     

茸鹿人工选育品种品系数量性状遗传参数的统计分析

对我国人工选育的梅花鹿和马鹿 6个品种品系的 2 0多个数量性状的遗传参数 ,进行了统计分析 ,结果表明 ,变异系数除鲜茸重的较高之外 ,其他很小 ;公鹿的留种率很低 ,茸重性状的选择差很大 ;遗传力和重复力均较高 ;世代间隔较短 ;鲜茸重的遗传进展和年改进量较大 ;梅花鹿种公鹿的种用年限较短 ,并明显低于马鹿的 ;梅花鹿品种品系间和马鹿亚种间杂交F1茸重性状和繁殖成活率性状的杂种优势率非常显著 (P <0 0 1 )。此项统计分析为茸鹿的优质高效育种、提高纯繁选育速度、杂种优势利用、杂交培育新品种和育种规化及模式提供了科学依据。     

Genetic variation in susceptibility to Marek's disease in a commercial broiler population.

Two commercial broiler pure lines that were previously identified to differ in their susceptibility to Marek's disease (MD) were line-crossed to generate an F1 population. Eight F1 males were randomly mated to four or five F1 females to produce an F2 test population that would be segregating for genes affecting MD. All F2 progeny (four hatches) were pedigreed at hatch and placed in colony houses as nonvaccinated. At 5 days of age, they were challenged intraabdominally with MD virus RB1B. Clinical signs, mortality, and gross and microscopic lesions were recorded during the MD challenge. At 8 wk postchallenge, all remaining birds were euthanatized and necropsied. During the MD challenge of the first two hatches, we observed that several severely stunted broilers originated from certain families and the differences in body weight among birds appeared as early as 3 wk postchallenge. To confirm this observation, body weight at 6 wk postchallenge was determined for all surviving birds in hatches 3 and 4 (n = 242). Genetic variation in body weight among broiler sire families was apparent; the average body weight for males at this time was 2.07 kg, whereas with females, it was 1.87 kg. At least 12.2% of the broilers, including both sexes, weighed less than 1 kg ("severely stunted") at this time. The incidence of these growth-stunted birds within each broiler sire family ranged from 0 to 26% and for dam families, 0 to 60%. Correlation analyses between stunting and other MD-associated traits revealed that the incidence of stunting had a significant and positive association with paralysis (r = 0.50). Therefore, the data suggest that there may be a genetic component affecting body weight loss during MD infection. The genetic component is speculated to affect susceptibility to MD paralysis with an indirect effect on the body weight of birds. The significance of this finding is best exemplified by the identification of a broiler sire family with over 26% of its progeny affected by this MD-associated trait.     

Dam and Sire Effects on Sperm Penetration of the Perivitelline Layer of Eggs Produced by Two Strains of Commercial Turkeys

The reproductive performance of 2 commercial turkey breeder lines was examined using reciprocal crosses between sires and dams of each line. One line had been selected using artificial inseminations performed at biweekly intervals, whereas the second line had been selected using inseminations performed at weekly intervals. The hypothesis was proposed that sires and dams of the 2 lines differ because of different abilities for sperm to penetrate the inner perivitelline layer (IPVL) and fertilize eggs.Fertilized eggs to hatch poults for the experiment were obtained from the primary breeders and were incubated using conditions recommended by the industry. Hens (n = 72) and toms (n = 15) from each strain were identified and reared in preparation for a reproductive cycle using commercially accepted standards. Beginning just prior to the onset of egg production and at weekly intervals thereafter, half of the hens were inseminated with semen from males of the same line, whereas the remaining half received semen from the opposite line. Eggs were collected from the pens daily and set in incubators to determine fertility and embryo survival. At biweekly intervals 3 eggs per pen were used for counting sperm penetration holes in the IPVL. Data were collected for fertility, hatchability, and time that embryos died for each of the pens. Dam and sire affected IPVL penetration independently. A dam by sire interaction influenced fertility, whereas hatchability was affected only by dam. Thus, it is concluded that selection of dam and sires for commercial breeders alters IPVL sperm penetration ability of hens as well as egg-binding ability of sires.     

几株鸡新城疫病毒的分离鉴定及其基因型分析

从几个发生禽病的地区分离到6株病毒,经过血凝试验、血凝抑制试验、中和试验、分子生物学试验等确定为鸡新城疫病毒;根据GenBank公布的新城疫F基因强弱毒株相关基因序列设计合成1对特异性引物,扩增出的F基因片段长度约为610 bp,测序后进行序列比对,并分析其核苷酸序列和氨基酸序列,结果显示,有3株具有新城疫强毒株特性,同时还具备新城疫Ⅶ基因型特征,另外根据平均死亡时间(MDT)、脑内致病指数(ICPI)和静脉致病指数(IVPI)指标测定结果,最终判定这3株是新城疫强毒株且属于基因Ⅶ型,其余3株病毒分离株与La Sota的核酸序列同源性与氨基酸序列同源性均为99%。