哲罗鲑与细鳞鲑属间远缘杂交的初步研究

Intergeneric hybridizations between Hucho taimen and Brachymystax lenok

通过性激素药物诱导和全人工繁育技术对野生哲罗鲑(Hucho taimen)与细鳞鲑(Brachymystax lenok)进行远缘杂交。结果表明,哲罗鲑(♀)×细鳞鲑(♂)(HB,正交实验组)杂交的受精率、发眼率、孵化率和仔鱼上浮率与其双亲自群繁育效果无显著性差异(P>0.05),而且在胚后的不同发育时期HB杂交子代的死亡率和畸形率均低于哲罗鲑自繁(HH)和细鳞鲑自繁(BB)对照组。在内源性营养时期(卵黄囊吸收早期),HB、HH和BB的仔鱼体质量分别呈负增长、正增长、零增长趋势变化;在混合营养时期(开口-转口时期),HB和BB组鱼体质量呈正增长趋势变化,HH组体质量呈负增长趋势变化;在外源性营养时期(驯化时期),HB、HH和BB的鱼体质量均呈正增长趋势变化;无论在哪个时期实验组和对照组的体长均呈正增长趋势变化。细鳞鲑(♀)×哲罗鲑(♂)(BH,反交实验组)的杂交经过2年多批次实验均未得到成活杂交子代,但在胚胎发育阶段BH的杂交受精率、发眼率均显著高于双亲(BB、HH)自繁对照组(P<0.05),但其孵化率显著低于双亲对照组(P<0.05),BH杂交子代在破膜后1～2h内即死亡,刚破膜的仔鱼尾干中后段至尾鳍部分盘绕于卵黄囊表面不能伸展,且所有破膜仔鱼的尾干中后段均存在充血点,本研究认为,这种反交[细鳞鲑(♀)×哲罗鲑(♂)]子代不能成活的原因可能是由远缘杂交受精卵核质不相容所导致。

In the present study,distant hybridizations between wild Hucho taimen and Brachymystax lenok were carried out by gonadal hormone induction and artifical propagation.The result showed that there were no significant differences in fertility rate,eyed rate,hatching rate and larva floating rate of the hybrid between Hucho taimen（♀）and Brachymystax lenok（♂）（HB,orthogonal experiment group）（P〉0.05）.The malformation rate and mortality rate of the hybrid（HB）at different stage of post-embryonic development were lower than that of control groups（HH,BB）.The body weight of HB,HH and BBlarvae showed negative growth,positive growth and zero growth respectively at the stage of endogenousnutrition. At the mixed feeding stage,the body weight of HB and BB showed positive growth,while the hybrid of HH showed negative growth.At the exogenous nutrition stage,the body weight of HB,BB and HH were all positive growth.No matter at which stage,the change tendency of body length increased in all groups.The hybrid between Brachymystax lenok（♀）and Hucho taimen（♂）（BH,reciprocal cross group）were not a live in the past 2 years.However,the fertility and eyed rate of BH were significantly higher than that of HH and BB（P0.05）,while the hatching rate were significantly lower（P0.05）. The larvae died within 1 to 2 hours after hatching.It was observed that the tail of yolk-sac larve couldn’t stretch around the yolk,and there were hyperemia in the middle and posterior segment of the tail.The reason why the hybrid between Brachymystax lenok（♀）and Hucho taimen（♂）couldn’t survive might was the karyoplasms of the gametes from Brachymystax lenok and Hucho taimen by distant hybridization were not compatible.