Study On Hybridization Effection And Genetic Diversity Between Geographical Populations Of Macrobrachium Rosenbergii

1. Study on Hybrid of Burma Introduced and Zhejiang Locally-Cultured Populations of Giant Prawn (Macrobrachium Rosenbergii deMan) and SRAP MarkerGiant freshwater prawn (Macrobrachium rosenbergii) belongs to Macrobrachium, Decapoda, Palaemonidae. It is one of the most popular freshwater prawns cultivated in China after introduced from Malaysia last century. However, their producing traits were degenerated apparently because of inbreeding for twenties years. So we imported some prawns from Burma to mate with the Zhejiang cultured populations to improve their culture characters. Four populations, designated A, B, C and D, were obtained respectively from crossings between Burma introduced population (BP) ( ♀ ) and Zhejiang cultured population (ZP) (♂) , ZP (♀) and BP (♂) , ZP (♀) and B (♂),ZP (♀) and A(♂). In the study, 6 populations (BP, ZP, A, B, C and D) were compared on the ability of reproduction and the growth velocity. The results demonstrated the egg-carrying capability of BP, B, C and D was significantly higher than ZP and BP, the average zoea output of BP, A, B and D was significantly higher than that of ZP and C. During the rapid growth period (from Aug 2 to Sep 28), the growth velocity of BP was significantly higher than that of ZP, B and C, A growed significantly faster than ZP and B, D significantly faster than ZP, and no significant difference between the other populations was found. It is the first report of application of SRAP (sequence-related amplified polymorphism) to make a comparative analysis on genetic diversity of giant freshwater prawn among six groups (BP, ZP, A, B, C and D). The proportion of polymorphic loci was 60.3%, 55.6%, 60.7%, 63.3%, 61.9% and 64.1% in six populations and Shannon index Ho was 0.185, 0.175, 0.196, 0.192, 0.193 and 0.197, respectively. It suggests that the genetic diversity of introduced population is higher than that of cultured population. All the results above mentioned demonstrated that the genetic diversity and cultural traits could be improved by crossing with the introduced population. And the SRAP markers identified in this study can provide a useful reference for future giant freshwater prawn breeding efforts.