Comparative study on the growth, survival, gonad development and trait segregation of F2 hybrids and their grandparent species (Crassostrea ariakensis and C. hongkongensis)
Comparative study on the growth, survival, gonad development and trait segregation of F2 hybrids and their grandparent species (Crassostrea ariakensis and C. hongkongensis)
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DOI：
10.1016/j.aquaculture.2021.736757
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发表时间：
2021-04-18
期刊：
影响因子：
4.5
通讯作者：
Yu, Ziniu
中科院分区：
文献类型：
--
作者：
Qin, Yanping;Li, Xingyou;Yu, Ziniu
在以往的研究中，我们发现近江牡蛎和牡蛎的F-1杂种具有较好的遗传多样性。hongkongensis比亲种生长快，成活率高。进一步进行F1代种内杂交，进一步了解了其性状分离的规律，为选育耐盐性强、生长快的新品系指明了方向。本研究系统地分析了杂种F-2代及其祖父母种的生长、存活、育性和性状分离。ariakensis和C. hongkongensis）。结果表明，三组幼虫的受精率、卵裂率、D幼虫率和成活率均无显著差异，但F-2代和C. ariakensis显著高于C. hongkongensis在第12和16天发生。在高盐现场（竹林塘），杂种F-2的壳高和存活率均显著高于C。hongkongensis的第90天至第360天。但在低盐度区（大丰河），F-2代的壳高始终高于C。但三组间的存活率无显著性差异。根据鳃水管孔的大小和数量将F-2分为3种类型，只有F-2-A（如C。ariakensis）和F-2-H/A（中间型）在高盐度环境中存活。此外，在杂种F-2中鉴定出3个ITS-2基因片段，只有A（如C。在高盐条件下，HA（与F-1杂交种相似）和HA（与F-1杂交种相似）均存在。生殖腺组织石蜡切片证实，三种类型的F-2杂种都能育，并能产生成熟的配子。综上所述，通过综合比较分析，我们证实了F-2-A和F-2-H/A杂种在耐盐性和生长速度方面明显优于其祖亲本，具有作为新品系基础的潜力。
In previous studies, we showed that F-1 hybrids of Crassostrea ariakensis and C. hongkongensis had faster growth and higher survival rates than the parent species. Further intraspecific crossing of F-1 hybrids allowed us to further understand the law of trait segregation and indicated a potential direction for breeding of a new strain with high salinity tolerance and fast growth. In this study, we systematically analyzed the growth, survival, fertility and trait segregation of F-2 hybrids and their grandparent species (C. ariakensis and C. hongkongensis) at two sites. Our results confirmed that there were no significant differences in fertilization, cleavage, D larval and survival rates among the three groups of larvae, but the shell heights of F-2 hybrids and C. ariakensis were significantly higher than those of C. hongkongensis on the 12th and 16th days. At the high salinity site (Zhulin Pond), the shell heights and survival rates of the F-2 hybrids were significantly higher than those of C. hongkongensis from the 90th to the 360th day. However, at the low salinity site (Dafeng River), the F-2 hybrids consistently had higher shell heights than C. ariakensis, but there was no significant difference in the survival rates among the three groups. F-2 hybrids were classified into three types based on size and number of holes on the gill water tubes, and only F-2-A (like C. ariakensis) and F-2-H/A (intermediate form) were confirmed to survive at the high salinity site. Moreover, three number of ITS-2 gene fragment were identified in the F-2 hybrids, and only A (like C. ariakensis) and HA (like F-1 hybrids) existed at the high salinity site. Paraffin sections of gonad tissue confirmed that all three types of F-2 hybrids were fertile and could produce mature gametes. In summary, through this comprehensive comparative analysis, we confirmed that F-2-A and F-2-H/A hybrids had clear advantages in terms of high salinity tolerance and fast growth over their grandparent species, and had potential to be used as the foundations of a new strain.