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为了评估太平洋牡蛎与近江牡蛎能否产生远缘杂种优势,于2010年5月,以成熟的两种牡蛎亲本为材料开展了2×2远缘杂交研究,由长牡蛎自繁组GG(Crassostrea gigas♀×C.gigas♂)、近江牡蛎自繁组AA(C.ariakensis♀×C.ariakensis♂)、正交组GA(Crassostreagigas♀×C.ariakensis♂)、反交组AG(C.ariakensis♀×C.gigas♂)4个实验组组成。分析了子代早期表型性状和杂种优势,并对杂交子代进行了遗传鉴定。结果表明:GA杂交组与AG组的受精强度具有不对称性。幼虫浮游期间,表型性状的中亲杂种优势几乎为0,GA组生长与存活性状表现出积极的单亲杂种优势,而AG组则具有明显的远交衰退现象;幼虫早期表型性状受到母本效应影响,而后减弱。变态期间,GA组变态率较高,得到了大量杂交稚贝;而AG组变态率极低,仅获得了72个杂交稚贝。稚贝培育期间,稚贝表现出中亲生长劣势与存活优势;GA组具有明显的单亲生长与存活优势,而AG组则表现出生长劣势并具有一定程度的存活优势。利用复合COI及ITS2鉴定了种间杂交子结果表明:正反交组杂交子均为真正意义上的两性融合杂交子。实验获得了具有显著杂种优势的GA组杂交子,为现有牡蛎的遗传改良提供了新的方向。
In order to evaluate whether Pacific oyster and Oyster overseer can produce distant heterosis, a 2 × 2 distant hybridization study was conducted in May 2010 using two mature oyster parents as material, and Crassostrea gigas ♀ × C.gigas♂, C.ariakensis♀ × C.ariakensis♂, Crassostreagigas♀ × C.ariakensis♂, C.ariakensis♀ × C.gigas♂) 4 experimental groups. The early phenotypic traits and heterosis of progeny were analyzed, and the genetic identification of hybrid progeny was carried out. The results showed that the fertilization intensity of GA hybrid group and AG group was asymmetric. During the larval period, the mid-parent heterosis of phenotypic traits was almost zero, while the growth and survival traits of GA showed positive single-parent heterosis, while the AG group had obvious distant crosses. The early phenotypic traits of larvae were affected by female parent Effects, then weakened. During metamorphosis, GA metamorphosis rate was higher, a large number of hybrid juveniles were obtained; while AG metamorphosis rate was extremely low, only 72 hybrid juveniles were obtained. During juvenile spawning, juveniles showed the advantage of midgut growth and survival; GA had obvious single-parent growth and survival advantages, while AG group showed growth disadvantage and had a certain degree of survival advantage. The results of interspecific hybridization using composite COI and ITS2 indicated that all the hybrid progeny and reciprocal hybrids were true hybrid amphipathic hybrids. GA hybrids with significant heterosis were obtained experimentally, which provided a new direction for genetic improvement of existing oysters.