大口黑鲈北方亚种、佛罗里达亚种及“优鲈3号”杂交F1子代生长性能及遗传多样性分析

Analysis of growth trait comparison and genetic diversity of F1 progeny on cross species of southern largemouth bass,northern largemouth bass and“Youlu No.3”

为获得兼具生长性能好、抗逆性强的大口黑鲈(Micropterus salmoides)新品种系,以引进的大口黑鲈北方亚种群体(N)、佛罗里达亚种群体(S)及大口黑鲈新品种“优鲈3号”(T)为亲本,设计3种杂交组合方式通过杂交获得3个F1子代群体:“优鲈3号”♀(T)×佛罗里达亚种♂(S)(TS群体)、“优鲈3号”♀(T)×北方亚种♂(N)(TN群体)、佛罗里达亚种♀(S)×北方亚种♂(N)(SN群体)。采用9对微卫星引物对3个子代群体的遗传结构及遗传多样性进行分析,CWT标记后对生长性能进行同塘对比。结果显示,9对微卫星引物在96个子代个体中都能扩增出稳定清晰的条带,共获得107个等位基因,其中TS群体、TN群体、SN群体平均等位基因数分别为4.2、4.2、3.4,平均期望杂合度(He)分别为0.6003、0.5734、0.4542,平均观测杂合度(Ho)分别为0.5590、0.6042、0.4722,平均多态信息含量(PIC)分别为0.521、0.511、0.3823,TS群体的遗传多样性高于其他两种组合。对2~7月龄的生长性状进行多重对比分析发现,TS群体在各月龄段的绝对增长率高于其他组合。结合生长性能及遗传多样性可知,TS杂交组合较优,研究结果可为大口黑鲈进一步的良种选育及遗传改良提供科学思路。

Largemouth bass Micropterus salmoides,one of the most important freshwater breeding species in China,has an annual production of more than 450,000 tons.However,there are some problems in the breeding of Micropterus salmoides.To obtain a new species of Micropterus almoides with good growth performance and strong resistance,the introduced northern subspecies of Micropterus salmoides(N),Florida subspecies(S)and the new variety of Micropterus salmoides called“Youlu No.3”(T)were taken as breeding parents.We obtained three F1 progeny groups by hybridization and analyzed the genetic structure and genetic diversity of them by using 9 pairs of microsatellite primers.After CWT markers,the three F1 progeny groups were compared with ones from the same pond in terms of growth performance.The results showed that the 9 pairs of microsatellite primers can be amplified into stable and clear bands in all of the 96 individuals.In total,107 alleles were obtained.The average number of alleles in the hybrid population of the“Youlu No.3”(T)and the Florida subspecies(S)(TS group),the hybrid population of the“Youlu No.3”(T)and the northern subspecies(N)(TN group)and the hybrid population of the Florida subspecies(S)and the northern subspecies(N)(SN group)was 4.2,4.2 and 3.4.respectively,the average expected heterozygosity(He)was 0.6003,0.5734 and 0.4542.The average observed heterozygosity(Ho)was 0.5590,0.6042 and 0.4722,the average polymorphic information content(PIC)was 0.521,0.511 and 0.3823.We could discover that the genetic diversity of the TS group was higher than that of the other two hybrid groups.Through the multiple comparisons of the growth traits at the age of 2-7 months,the result showed that the absolute growth rate of TS group at each age was higher than that of other combinations.Combining the growth performance and the genetic diversity,we could draw the conclusion that the genetic diversity and growth performance of the hybrid offspring were improved,and the growth performance and the genetic diversity of TS hybrid combination was better than that of other combinations.So,the TS hybrid group could provide a scientific basis for the breeding and the genetic improvement of Micropterus salmoides,it can also provide some good seed support for the industrial development of Micropterus salmoides.