Study on effects of multiple spawning on growth and genetic structure of progeny of Macrobrachium rosenbergii

Abstract:

In order to improve the quality of larvae of Macrobrachium rosenbergii,growth performance of progeny of 5 spawning batches(Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅴ) were checked by one-way completely randomized design. The results indicated that, the number of larvae increased with spawning number increasing, and the first three spawning batches had higher survival rate. The ranks of AGR were Ⅲ > Ⅱ > Ⅴ > Ⅳ > Ⅰ, Ⅱ,Ⅲ spawning batches showed obvious growth advantage after AGR comparison by LSD. Survival rate of Ⅰbatch was significantly higher than other four batches. Variation coefficient of body weight of first three spawning batches was lower than last two. It showed the figure of first three spawning batches were more tidy. The quantity of female shrimp atⅠ, Ⅱ, Ⅳ, Ⅴ batch is greater than males after 60 days feeding, but the sex ratio (♀/♂) of Ⅲ meets 1:1. Microsatellite markers were used to analyze the genetic diversity and genetic differentiation of 5 spawning batches. The results showed that:polymorphism information content (PIC) of 5 spawning batches in order was Ⅱ(0.586 3) > Ⅰ(0.583 5) > Ⅴ(0.560 2) > Ⅲ(0.560 1) > Ⅳ(0.555 8). These all were highly polymorphic. The longest genetic distance(0.017 0) was between Ⅰ batch and Ⅴbatch, the shortest genetic distance(0.000 3) was between Ⅳ batch and Ⅴbatch. The genetic relationships among each offspring batch were very close. It indicated that there were no significant differences of genetic structure among 5 spawning batches.