中国明对虾2个群体的杂交子一代早期分析

目前,对虾研究主要集中在基础遗传学和遗传改良的潜力研究等方面[1,2].不同的地理群体代表不同的遗传资源,尤其是对虾人工养殖迅速发展的情况下,对不同的群体生长发育性状特点进行评估是非常重要的.遗传改良的目标是提高对虾人工养殖群体的产量,这就需要育种计划不仅要建立在对虾自然群体相关性状差异的研究上,还需要进一步了解不同发育阶段主要经济性状的遗传特性.对虾幼体生长情况和存活率一直都是养殖者和科学工作者关注的问题.已经有研究证明美国大西洋牡蛎和港湾扇贝群体间在幼体生长发育和存活率方面存在遗传差异[3,4].杂种优势在生物界是一个普遍的现象.     

凡纳滨对虾(Litopenaeus vannamei)不同品系生长与耐高盐性状配合力及杂种优势分析

凡纳滨对虾(Litopenaeus vannamei)是优质经济虾类,为培育出具有更多不同优良经济性状的优质亲本,亟需开展杂交育种工作。以凡纳滨对虾5个不同品系进行不完全双列杂交产生的F1代资料为分析对象,利用统计学和混合线性模型对生长及耐高盐性状进行配合力和杂种优势分析。结果显示,对于生长性状,5个品系中检测到的一般配合力(GCA)效应值较低,实验环境下生长性状主要受特殊配合力的影响,Z♂×Z♀、P♂×XH♀2个组合生长性状的非加性效应明显,特殊配合力(SCA)效应值分别为0.69和0.30;对于耐高盐性状,品系P、S的GCA效应值最高,分别为0.83和0.53,P♂×XH♀、S♂×S♀2个组合耐高盐性状SCA效应值最高,分别为2.67和3.37;生长和耐高盐性状配合力方差组分结果显示,3个性状的特殊配合力方差占表型方差比例均高于一般配合力;5个杂交组合中体质量和高盐耐受性状的平均杂种优势范围分别为–19.23%~18.07%和–10.50%~20.97%。P♂×XH♀组合在生长和耐高盐性状方面杂种优势明显,可以考虑加强该组合在选育及生产方面的应用。     

三个文蛤家系双列杂交设计在两种环境下的配合力及杂种优势分析

A 3×3 complete diallel cross comprising three families of the clam Meretrix meretrix(P1, P2 and P3) was used to determine the combining ability of parental families and heterosis of F1 under indoor and openair environments for growth traits. Analysis of variance for shell length and whole body weight indicated highly significant cross effects, environment effects and the interaction of cross by environment. General combining ability(GCA) and specific combing ability exhibited great variation among crosses and between two environments. Pooled over environments, P2 was the top combiner among the three parental families for both traits studied. The cross of P1 and P3 had the highest SCA. Additionally, significant reciprocal effects were observed. For individual environment, about half of the crossbred combinations showed favorable Mid-parent heterosis(MPH)(1%) for the shell length and whole body weight. Our data has shown that non-additive genetic and reciprocal effects constituted the major sources of genetic variation for both shell length and whole body weight, which indicates that crossbreeding among selective families could further explore the heterotic effects.     

Heterosis and heritability estimates for the survival of the Pacific white shrimp (Litopenaeus vannamei) under the commercial scale ponds

The aim of the present study is to detect the potential of the base population from diallel crosses of eight introduced strains of the Pacific white shrimp(Litopenaeus vannamei) for improving the yield. Heterosis and heritability were estimated for pond survival at commercial farm conditions for the base population that included 207 full-sib families from a nested mating design by artificial insemination. Among all the hybrids,the heterosis ranged from –11.37%(UA1×UA2) to 20.53%(UA3×SIN) with an average of 0.953%. The results showed that more than half of the hybrids(51.85%) have negative heterosis for survival rate, but most of the hybrids with positive heterosis have high estimates. The high proportion of negative heterosis for survival rate reminders us that the survival trait also should be considered in the crossbreeding program to avoid yield decrease. However, high positive heterosis manifested in most of the hybrids for survival indicates the usefulness of these hybrids for improving the survival to obtain higher yield by crossbreeding in this breeding program. The heritability estimate for pond survival was 0.092±0.043 when genetic groups were included in the pedigree, and it was significantly different from zero(P0.05). The results from this study also indicated that significant improvement for survival is possible through selection in L. vannamei.     

海带杂种优势苗种繁育技术研究

用生物反应技术进行海带配子体克隆的连续培养,将丝状体克隆细胞粉碎后,用两系法培育杂种优势苗种.实验结果表明,雌、雄海带配子体克隆细胞的日增重速率可达14.03%和13.87%,经42d培养增重6.9倍和6.8倍;雌、雄配子体克隆细胞杂交16d,排卵率为100%;培养40d后幼孢子体长度为2~3cm,经海上养殖实验,初步筛选出了一个较好的杂交组合.     

合浦珠母贝3个养殖群体双列杂交F1代的生长和遗传分析

为开展合浦珠母贝(Pinctada fucata)遗传改良和培育优质新品种,作者利用合浦珠母贝北海养殖群体(B)、徐闻养殖群体(X)和三亚养殖群体(S)进行双列杂交,获得3个种群内自繁群体及6个种群间杂交群体。对8月龄F1代的壳长、壳高、壳宽和体质量4个生长性状进行了测定,计算了各组合的一般配合力、特殊配合力及杂种优势。结果表明,杂交组合的各性状值普遍高于自繁群体,其中S(♀)×B(♂)和S(♀)×X(♂)杂交组合的各性状值极显著高于其他组合。三亚群体各性状的一般配合力最大,S(♀)×X(♂)组合各性状特殊配合力最大,其次是S(♀)×B(♂)组合。杂交子一代4个生长指标均表现出一定程度的杂种优势(0.24%~52.62%)。不同杂交组合间和不同性状间的杂种优势存在差异,其中,S(♀)×B(♂)杂交组合杂种优势明显,其反交组合B(♀)×S(♂)杂交优势程度不高,且在壳宽上表现出较低的杂种优势率(0.24%);S(♀)×X(♂)杂交组合杂种优势率比反交组合X(♀)×S(♂)高。体质量的平均杂种优势率均高于其他3个性状。该研究的结果表明杂交群体性状的改进为进一步选育奠定了基础。     

Studies on hybridization effects of different geographic populations of Chlamys farreri Ⅱ. The medium-term growth and development of Chlamys farreri populations from China and Russia and their reciprocal crosses

Abstract-Based on the research of juvenile (2, 3, 4 months) growth and survival of three popu-lations of two different geographic areas in Chlamys farreri from Russian and China and their F_1 hybridsderived from Chinese cultural population (CC)×Russian population (RW), Chinese wild popu-lation (CW)×Russian population (RW), Russian population (RW)×Chinese wild popula-tion (CW), the study of the medium-term (6, 8, 10, 12 months) growth and development ofChlamys farreri was carried out. The four determined results indicated that there existed different ex-tent heterosis (3%～52%) for the growth in three types of F_1 hybrids, and the offspring derived fromCC×R had a stronger heterosis among the crosses at the medium-term; the uptrend among traitsare wet weight>shell width>shell length>shell height, Chinese cultural population could be recog-nized as excellent parent, and seasonal variations influence very much on the daily increment and growthrate of each trait of Chlamys farreri and it is only able to     

栉孔扇贝不同种群杂交效果的初步研究 Ⅰ.中国种群与俄罗斯种群的杂交

对两个不同地理种群的栉孔扇贝的3个群体——俄罗斯种群(R)、中国种群野生群体(CW)和养殖群体(CC)及其3个杂交组合F1代生长发育各组合40～50只进行了3次测定比较研究.结果表明,在壳长、壳宽、壳高、活体重4个生长发育指标上均表现不同程度的杂种优势,2月龄时CW♀×R♂杂交效果最好;3月龄时3个杂交组合的杂种优势均较大,但差异不显著;4月龄时各杂交组合的杂种优势明显,尤其是活体重的杂种优势突出,以R♀×CC♂杂交效果最好;3个亲本群体各个性状的测定性能表现在2,3月龄以俄罗斯种群较好,4月龄以中国养殖群体较好.中国种群2月龄野生群体较养殖群体生长发育快,3月龄时其生长发育差异不显著,4月龄养殖群体生长发育快.     

杂交与三倍体诱导对海湾扇贝(Argopecten irradians)幼虫的复合作用

基于2×2交叉实验设计,通过杂交和6-DMAP等诱导处理,构建了二倍体自交组、二倍体杂交组、三倍体诱导自交组和三倍体诱导杂交组等四个实验组家系,探讨了海湾扇贝(Argopecten irradians)幼虫期生长及存活的杂种优势和6-DMAP诱导处理效应的复合作用。分别计算各家系的孵化率,测定了各家系幼虫期第1、5、10天幼虫个体的壳长以及第5天和第10天各家系幼虫的存活率。利用一般线性模型(general linear model (GLM))计算表型变量的原因方差组分,评估了杂交和6-DMAP处理对扇贝幼虫生长和存活的影响。结果显示:6-DMAP处理组孵化率要显著低于非处理实验组(P0.05)。三倍体诱导自交组第5天幼虫存活率显著低于其他组(P0.05),到第10天三倍体自交组全部死亡。三倍体诱导杂交组第10天存活率低于二倍体组但不显著(P0.05)。在第1天幼虫生长中,三倍体诱导杂交组幼虫壳长显著小于其他组(P0.05),第5天幼虫生长中,三倍体诱导杂交组壳长则显著大于其他组,而三倍体诱导自交组则显著小于其他组(P0.05)。在第10天幼虫生长中,二倍体自交组显著小于二倍体杂交组和三倍体诱导杂交组组(P0.05)。上述结果显示扇贝幼虫生长期的杂种优势和三倍体诱导效应间存在一定相互作用。     

红壳文蛤双列杂交及杂种优势分析

以广西(G)、江苏(S)和日本(J)3个文蛤群体中原种红壳文蛤进行双列杂交,获得了试验家系(Gg、Ss、Gs、Gj、Sg、Sj),比较其生长性能,并评估杂种优势。从生长来看,浮游期杂交组的日生长率大于自繁组;以江苏文蛤为母本的组合的壳长均显著大于以广西文蛤为母本的组合(P0.05),壳长受卵源影响极显著(P0.01)。稚贝和幼贝期,杂交组的日生长率均大于自繁组,杂交组合Gs的日生长率从13日龄至149日龄均最大;交配方式对壳长极显著影响(P0.01)。从存活率来看,杂交组的存活优势更明显,Gs的存活率几乎均最高。从杂种优势来看,杂交组从13日龄以后具明显的杂种优势,尤其是Gs在1—149日龄均呈正值。广西群体和江苏群体间建立了完全2×2双列杂交,中亲杂种优势一直大于0,且始终介于单亲杂种优势HGs和HSg之间。杂种优势潜力指数(hp)表明,1—5日龄的数值介于–1和1之间,未产生杂种衰退;13日龄后的数值均大于1,表明真正获得了杂种优势。杂种获得(hg)及13日龄后的超亲优势率均为正值,进一步说明壳长性状得到了明显改良。从壳色来看,子代的红壳个体占比为72.80%—76.49%,均得到明显提高。总之,杂交组合Gs的杂种优势最明显,为开展3个群体的杂交育种提供了参考依据。