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在杂交原种生产中常出现因品种间发蛾不一致而冷藏雄蛾的现象。为了解广西当家品种两广二号中系杂交原种生产中,对交品种雄蛾6℃冷藏24h对生产杂交原种质量的影响而设计试验。结果显示:932雄蛾6℃冷藏24h后与芙蓉雌蛾交配,芙蓉×932(冷)的有效卵圈率、产卵率、良卵率均显著低于芙蓉×932,并且芙蓉×932(冷)雌蛾单蛾产卵率和良卵率个体间开叉大。芙蓉雄蛾6℃冷藏24h后与932雌蛾交配,932×芙蓉(冷)的有效卵圈率、产卵率显著低于932×芙蓉;良卵率差异不显著。 相似文献
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为了加速雄蚕品种的实用化进程,对家蚕性连锁平衡致死系原种平28、平30的雄性黄卵和雌性黑卵的孵化率、各龄期减蚕率等进行了调查。平28雄卵、雌卵及平30雄卵、雌卵的二日孵化率分别为39.67%、40.67%与29.50%、36.50%,黄色雄卵孵化率低于黑色雌卵,品种间的二日孵化率达极显著差异。平28雄卵、雌卵及平30雄卵、雌卵1-4龄的减蚕率分别为11.34%、17.62%与9.60%、13.24%,雌性减蚕率高于雄性,品种间的4龄起蚕率达显著性差异。对影响孵化及减蚕率的原因进行分析认为:黄色雄卵在蚕种保护过程中,卵内胚胎除受致死基因的影响外,也许更易受到外界环境诸如光线等的不利影响;平衡致死系的致死基因可能对正常孵化的蚕儿会产生微弱不利影响,从而影响正常孵出蚕儿的生长发育。 相似文献
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在长期的养蜂生产中通过对工蜂产卵群进行深入观察 ,发现工蜂产卵群不外两种情况 :一是因失王时间长 ,导致工蜂产卵 ,二是看起来正常的蜂王却只产未受精卵也出现工蜂产卵。无论哪种情况都应早发现及时处理。对工蜂产卵群曾多次采用介绍蜂王的方式进行处理 ,结果大多不成功 ,往往越健壮的蜂王引起的排斥越强烈。有一次用间接法介绍成功一只老王 ,但老王产受精卵 ,工蜂继续产未受精卵。在检查工蜂产卵群时注意到 ,巢脾上总有几个王台 ,里面也有卵 ,但王浆很少 ,这说明蜂群群体有需要正常蜂王的本能。根据这一现象 ,我给工蜂产卵群调入小面积卵… 相似文献
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优质的产卵蜂王正常表现为:产卵时腹部膨大而伸长、行动稳重、健康、积极产受精卵并规律整齐、空房少、面积大,维持强群。而在蜂群繁殖期受多种因素影响,产卵蜂王出现多种“失常”行为和状态,不能充分发挥其作用,对蜂群的发展、生产造成损失。1蜂王非正常产卵蜂王可产受精卵与未受精卵。在正常蜂群中,产在王台和工蜂巢房内的受精卵孵化后,幼虫得到不同的食物,分别发育成级型分化的蜂王和工蜂;向雄蜂巢房中产的未受精卵发育成雄蜂。蜂王的职能主要是产卵和维持群体稳定,工蜂承担哺育、饲喂、清巢、采集、酿造、调节巢内温湿度、照料蜂王等全… 相似文献
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桑蚕原种“湘·7的母蛾二重交试验结果表明；母蛾重交两次比单交一次总产卵量和良卵数增加，不良卵率有所下降。母蛾与一雄蛾交配1小时后再与另一雄蛾交配3.5小时的交配方式，与对照单交4．5小时相比．其单蛾总产卵量和良卵数增幅分别达10．98%和11.16％，不良卵率下降13．93%。 相似文献
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抗保幼激素对桑蚕产卵性能及子代的影响 总被引：1，自引：0，他引：1
本文研究了抗保幼激素物质CA_1和YA_(20)对桑蚕产卵性能及子代(F_1)的影响,证明3、4龄添食均能完成生活世代,正常交配、产卵、但因三眠化,发育经过显著缩短,产卵数少,但叶卵转化率相近,且F_1生长发育及眠性未见受影响,全茧量、茧层量、万头收茧量稍有下降,但克蚁牧茧量却比对照区高约5%。 相似文献
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桑天牛长尾啮小蜂产卵及寄主识别行为的观察与研究 总被引：8，自引：6，他引：2
桑天牛长尾啮小蜂(Aprostocetus fukutai)是桑天牛(Apriona germari)卵期寄生蜂,研究其寄生机制对桑天牛的生物防治有重要意义。该寄生蜂的产卵行为主要包括桑天牛刻槽的定向搜寻、刻槽表面的检验、寄主卵检验、产卵寄生、标记等,其中刻槽表面检验的时间较长。选择试验显示,正常刻槽产卵桑枝对寄生蜂的引诱作用明显高于正常桑枝和取食桑枝。在刻槽未产卵桑枝、刻槽产卵未涂抹分泌物桑枝和正常刻槽产卵桑枝中,正常刻槽产卵桑枝对寄生蜂的引诱作用最强,并且刻槽检验时间、寄主卵检验率和寄生率等都显著高于前两个处理。已寄生刻槽对长尾啮小蜂的引诱作用明显低于未寄生刻槽。 相似文献
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中国系统一化性品种“灰色卵”,形态性状为姬蚕、白血、灰卵。卵色为银灰色,大多数卵的卵面平滑,水引较浅,少数卵(每一蛾区约有10粒)的卵面有1—2条皱纹。卵形正常,孵化良好,孵化后卵壳成乳白色,属自然突变产生的灰卵,由于该灰卵与以往文献上记载的Gr、Gr~(18)、Gr~L、Gr~K、Se、Gr~B、Gr~X、gr等灰卵在形态上差异很大,所以著者在1984年和1985年对其进行了遗传学研究、现将结果简述如下。将灰色卵雌与正常卵雄(品种为中108)杂交,F_1代全部是灰卵,F_2代全部是绿灰卵(近似灰卵与正常卵的中间型)、F_3代灰卵,绿灰卵,正常卵呈蛾区间分离,比例为1∶2∶1。而将正常卵雌与灰色卵雄杂交,F_1代全是正常卵,F_2代全是绿灰卵,F_3代灰卵、绿灰卵、正常卵的比例为1∶2∶1。以上结果表明该灰卵与有关卵壳色的灰卵遗传形式一样,系伪母性遗传的,并且呈不完全显性,基因没有致死作用,位于常染色体上。连锁分析:采用y(2)、lem(3)、L(4)、o~c(5)、E~(E1)(6)、q(7)、St(8)、Ia(9)、K(11)、ms(12)、ch(13)、U(14)、cts(16)、Bm(17)、nb(19)、rb(21)、or(22)、Nd(25)、Ym(26)等作不同染色体的标志基因进行连锁分析,结果,灰卵与第3,4,5,6,7,8,9,10,11,12、13、14、16、17、19、21、22、25、26等连锁群均呈独立遗传。而灰卵与第Ⅱ染色体的标志基因Y杂交后,F_1雌回交中108雄,RF_1代两区合计黄血产正常卵蛾为108,黄血产灰卵蛾为0,白血产正常卵蛾为0,白血产绿灰卵蛾为99。说明灰卵与黄血(Y)连锁,基因位于第Ⅱ染色体。基因定位:采用三点定位法,用普斑黄血正常卵蚕与姬蚕白血灰卵蚕杂交,F_1代雄回交姬蚕白血正常卵,饲养RF_1,调查斑纹血色的分离和RF_1产卵的卵色分离,计算重组值结果:RF_114区合计普斑白血产灰卵蛾为73,普斑白血产正常卵蛾为194,普斑黄血产灰卵蛾为1,普斑黄血产正常卵蛾为755,姬蚕白血产灰卵蛾为782,姬蚕白血产正常卵蛾为0,姬蚕黄血产灰卵蛾为189,姬蚕黄血产正常卵蛾为69,合计2063蛾。由此计算重组值,p~3—GrZ间的重组值为6.9％,Gr~Z—Y间的重组值为18,7,由于双交换的缘故,p~3—Y间的重组值较低、为25.5。综上所述,灰卵为伪母性遗传不完全显性的基因所支配,基因位于第Ⅱ连锁群6.9处(2—6.9)。特将此灰卵命名为镇江灰卵(Shenjiang greg egg)。基因记号为Gr~Z。该基因属灰卵复等位基因群 相似文献
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原种9·芙、7·湘发生变异蛾。用9·芙×7·湘正反交变异蛾与该户正常发育蛾作对照,调查单蛾产卵、良卵率、遗腹卵、两天实用孵化率、结茧率,结果为:单蛾产卵减少32.20％、反交减少48.69％,良卵率正交下降1.82％、反交下降2.92％,遗腹卵正交增加45.87％、反交增加53.60％,两天实用孵化率正交下降2.64％,反交下降1.85％,结茧率正交下降93.75％、反交下降75％。因此在制种过程中除按常规淘汰不良蛹、不良蛾外,还要淘汰变异蛾。 相似文献
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I.G. Gaigher 《African Zoology》2013,48(2):105-108
Female Labeo umbratus reach sexual maturity at a larger size than males and dominate the population in fish over 450 mm in length. The gonads are large (up to 20% of total body mass) and they have a high fecundity which increases linearly with an increase in body mass. Successful spawning is dependent on suitable floods during the spawning season which extends from November to March or April. Spawning apparently occurred in the impoundment. All females did not spawn simultaneously and evidence suggests that individuals might spawn more than once during a particular season. 相似文献
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Two "bitches" presented with histories of non-attainment of puberty were diagnosed as intersexes. Data on gross morphology, histology of the genitalia, and genetic sex using blood, skin and gonads were employed for the classification of the type of intersex in each case. Both cases were classified as true hermaphrodites. 相似文献
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Failures in the establishment of chromosomal, gonadal and phenotypic sex can cause intersexuality in dogs. Thus, diagnosis of chimaerism, mosaicism, sex reversal syndrome, and male or female pseudohermaphroditism in intersex individuals has to be based on the inspection of the chromosomes, gonads and the phenotypic appearance of the reproductive organs. In a study over two years, seven dogs of different breeds suspected to be intersexes were cytogenetically investigated. A sry-negative XX-sex reversal syndrome was diagnosed in a Jack Russel Terrier. In a mixbred dog a persistent Mullerian duct syndrome (PMDS) was found and a Border Terrier Dog showed an XX/XY chromosomal chimaerism. In further four dogs of different breeds, a female constitution of sex chromosomes was seen. As a sign of intersexuality each of these dog showed an enlarged clitoris. A differentiation between XX-sex reversal syndrome and female pseudohermaphroditism was not possible because there was no information on the internal genital tract and gonads available. 相似文献
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Effect of long‐term selection for improved growth on reproductive performance of giant freshwater prawn (GFP) Macrobrachium rosenbergii has not been reported in the literature. The present study aimed to measure correlated responses in reproductive traits and to estimate genetic parameters for these characters in a GFP population selected for high growth over ten generations from 2007 to 2016. A total of 959 breeding females (offspring of 515 sires and 810 dams) had measurements for seven reproductive traits (weight before spawn WBS; weight after spawn WAS; Fecundity FEC or number of larvae per female at hatching; first age to reach post‐larvae PLAGE; zoea (e) weight ZOEAWT; larval survival during hatchery phase SURV1 and survival from PL to tagging SURV2. The restricted maximum likelihood (REML) and mixed model analysis were used to estimate genetic parameters and evaluate selection responses for the seven traits studied. Our REML analysis showed that heritability for these traits ranged from 0.04 to 0.42 (SE: 0.19–0.28). Female body weight either before or after spawning had strong positive phenotypic correlations with fecundity (0.52–0.98). By contrast, the phenotypic correlations of WBS/WAS with larval and fry survivals were not significant (?0.08–0.05). Genetic correlations among fecundity‐related traits studied were not different from zero due to their high standard errors. Correlated responses in reproductive traits were measured by comparing least squares means of the selection line and control group. Females of the selected line for high growth had significantly greater weight before or after spawning than that of the control group. There were, however, no statistical differences between the two lines in the other traits. It is concluded that selection for high growth did not have detrimental impact on reproductive performance of breeding females in the present population of GFP. 相似文献
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黄鳝性逆转过程中性腺形态学初步观察 总被引：5，自引：0，他引：5
试验通过对性逆转过程中雌、雄鳝以及雌雄间体鳝的性腺的形态学进行观察 ,结果显示 ,雌鳝性腺大部分含肉眼可见的卵粒 ,但各时期卵巢的卵粒大小不一。雌雄间性阶段黄鳝性腺肉眼仅见不同形态的卵粒 ,部分卵粒极少 ;组织切片既可观察到卵母细胞 ,还可发现结缔组织纵隔和在纵隔上形成的管状结构的早期精细管 ;而雄鳝阶段黄鳝性腺多呈乳白色带有黑色斑点 ,带有较多且大的黑色斑点性腺可能是卵母细胞退化凋亡痕迹 ,其切面中有较稀疏精母细胞 ,可能属早期的精巢 ;乳白色性腺中黑色斑点极少 ,精母细胞相对较密集 ,可能是成熟期的精巢。试验表明黄鳝“性逆转”在形态学上具有明显的阶段性特征 相似文献
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Microscopic Evidence of the Opportunistic Reproductive Strategy and Early Sexual Maturation of the Small‐Sized Characin Knodus moenkhausii (Characidae,Pisces) 
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下载免费PDF全文 We investigated the reproductive biology of Knodus moenkhausii, an abundant small‐sized characin fish with broad occurrence in the Paraná River basin, Brazil. Specimens were collected monthly to determine fecundity, length at first maturity, reproductive period and spawning type. Gonads were macroscopically classified according to their form, size and texture in three different stages (immature, maturing or mature). Histological procedures were conducted to confirm gonadal developmental stages, and it was possible to notice that maturing females actually presented atretic oocytes, and all males that were macroscopically classified as immature, maturing and mature actually presented abundant spermatozoa in their gonads. Because of these discrepancies, a reclassification of gonadal maturations stages was needed after histological analysis, reinforcing its importance to studies on the reproduction of small characins. Reproduction occurred throughout the year though with two peaks. The length of the smallest mature individuals was 13 mm SL for males and 24 mm SL for females. Despite presenting relatively small batch fecundity, some life history traits such as early reproduction, multiple spawning throughout the year, in association with known opportunistic feeding habits, explain the high abundance of this species in locations where it occurs. 相似文献
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Theresa Lasiak 《African Zoology》2013,48(3):250-252
Gonadosomatic indices, macroscopic and microscopic examinations of gonads were used to establish the breeding cycle of Monodactylus falciformis. Spawning took place between October and February and evidence for serial spawning is presented. 相似文献
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Egenvall A Bonnett BN Häggström J Ström Holst B Möller L Nødtvedt A 《Journal of Feline Medicine and Surgery》2010,12(12):948-959
The aim of the study was to describe patterns of morbidity, as reflected by reimbursed claims for veterinary care among cats covered by a Swedish insurance company during 1999-2006. The annual incidence rates of having at least one veterinary care event were calculated overall and stratified by sex, age, breed, diagnosis and urban/other location. The total rate was 875 (95% CI 858-892) cats with claims per 10,000 cat-years at risk. The Siamese, Burmese, and the Abyssinians had high rates of claims, compared to the Norwegian Forest cat, the Maine Coon, the European Shorthair and domestic cats. The most common causes for insurance claims were trauma, gastrointestinal and lower urinary tract problems and there was substantial breed, sex and age variation for certain problems. For example, among cats under 9 years of age, the rate for lower urinary tract problems was 2-3 times higher in males than females. 相似文献
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In 3 relatively large samples intersexuality was found in 0.2 % of the pigs. Litters with intersexes had a deficit of male piglets. The total number of piglets in such litters was correspondingly reduced. Pig losses until the age of 5 weeks were reduced in intersex litters. Other malformations, especially scrotal hernia, were more common in these litters than in normal ones.Forty-five intersexes showed big variation in the development of sexual organs. All had testicles, however. Thirteen (29 %) were so-called true hermaphrodites whereas 32 were male pseudohermaphrodites.All 42 cases being karyotyped were genetical females. There are arguments for genetical predisposition for the defect. The hereditary transmission is probably complicated. In any case it is not monogenic recessive.Practical consequences of the defect are: almost complete sterility, slaughter losses due to bad smell and taste of the meat and increased risk of cassation (local or general inflammations), increased frequency of other malformations in litters holding intersexes. 相似文献