The growth and survival at early stage between inbred lines and hybrid systems were compared between full-sib inbreeding families and hybridization of two full-sib inbreeding in two families, A pedigree ( F6 ) and B ( F3 ) , of swimming crab Portunus trituberculatus with different genetic purification in order to breed new families. There were four test groups, including two inbreeding groups F66( A♀×A♂) and F33( B♀×B♂) and two hybrid groups F63( A♀×B♂ ) ,and F36( B♀×A♂) . In terms of reproductive performance, there were significantly higher fecundity, relative egg carrying production and relative larvae releasing production in the inbreeding groups than those in the hybrid groups, especially the fecundity (P<0. 05). Within the inbreeding groups, however, there was higher relative egg carrying production and relative larvae releasing production, without significant difference, indi-cating that the hybrid group showed no advantage in reproductive performance. The growth and survival of juveniles from stage II to stage V revealed that the hybrid groups F63 and F36 had general heterosis of 14. 38%-25. 05% in body weight, and 5. 57%-10. 27% in full carapace width, higher than the inbreeding groups of F66 and F33 . The overall growth rate was ranged as the following:F63>F66>F36>F33 . There was higher heterosis in F36 group than F66 and F63 group than F66 group. The overall survival heterosis of 22. 49%-36. 67% was found in the hybrid groups, higher in F63 group than in F66 group, and higher in F36 group than in F66 group. The findings indicated that the hy-brid groups did not show the heterosis in reproductive performance, instead in growth and survival at the early growth stage, which provides foundation for further breeding of swimming crab.%为培育三疣梭子蟹Portunus trituberculatus新品系,选择差异较大的两代自交家系进行家系内自繁和家系间杂交的试验,建立了三疣梭子蟹近交系和杂交系,并比较了其繁殖性能和子一代早期生长与存活的情况。三疣梭子蟹A家系为自交F6, B家系为自交F3,均为基因纯化程度不同的两个家系,试验设计自交组F66( A意×A裔)、 F33( B意×B裔)和杂交组F63( A意×B裔)、 F36( B意×A裔)4个试验组。繁殖试验结果表明,两个自交组亲蟹的抱卵量、排幼量和单位体质量抱卵量均比两个杂交组大,且均显著高于F63组(P<0.05),而自交组的单位体质量排幼量和孵化率也均比杂交组大,但无显著性差异(P>0.05),表明在繁殖性能上,杂交组并未表现出杂种优势。幼蟹的早期生长和存活试验结果表明,杂交使域期幼蟹至吁期幼蟹的生长和存活两个表型性状都得到了改良,杂交组( F63和F36)在早期生长阶段相对于自交组( F66和F33),体质量的总体杂种优势率为14.38%~25.05%,全甲宽的总体杂种优势率为5.57%~10.27%,体质量和全甲宽的增长速度各组均为F63>F66>F36>F33,其中F36组相对于F33组各表型性状的杂种优势均明显大于F63组相对于F66组的杂种优势；杂交组存活的总体杂种优势率为22.49%~36.67%,其中F63组相对于F66组存活的杂种优势明显大于F36相对于F33组的杂种优势。研究表明,三疣梭子蟹杂交组在繁殖性能方面虽未表现出杂种优势,但在早期生长和存活方面表现出了显著的杂种优势,这可为进一步开展三疣梭子蟹选育工作提供参考±据。
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