RAPD ANALYSIS OF DIPLOID GYNOGEN POPULATIONS OF ALLOTETRAPLOID HYBRIDS OF RED CRUCIAN CARP(♀) X COMMON CARP(♂)

Following activation by scatter scale carp sperm（a variety of common carp) that were UV-irradiated for 30 min, the diploid eggs stripped from F10female allotetraploid hybrids of red crucian carp（Carassius auratus red var.,♀) X common carp（Cyprinus carpio L.,♂), without or with the cold shock at0-4℃ for 30min, developed in normal live first generation diploidgynogens（G1).Interestingly, like the diploid F2hybrids, these diploid gynogens（G1) also produced diploid eggs. Without the treatment for doubling the chromosome number, the diploid eggs produced by the first generation gynogens, developed into the second-generation gynogens（G2) subjecting to activation by UV-irradiated scatter scale carp sperm. In the present paper, genetic heterogeneity and molecular markers were analyzed by RAPD technique in the first and second generation of artificial induced diploid gynogen population generated by the gynogenesis of F10allotetraploid hybrids. Of one hundred and thirty-four 10-nucleotide-long random primers used in the preliminary analysis, 53 primers produced wel-l amplified and reproducible band patterns.They were selected and used in the further analysis.The number of loci detected in the firs-t generation gynogen population and second-generation gynogen population were 541、 511, and the number of polymorphic loci were 70、 52, respectively.The percentage of polymorphic loci（12.94% )was considerately higher in the G1than that（10.18% ) of G2.The average genetic distances estimated byLynchp s index were 0.0732、 0.0464, respectively.Theresults showed that the genetic diversity of G2was significantly decreased after two continued generation gynogenesis, and the genetic purity of G2 was considerately higher than that of G1.Two primers, such sa S50、 S223, were observed to produce specific bands, and these bands could beused as molecularmarkers for discriminating the firs-t generation diploid gynogens fromthe second-generation diploid gynogens.A phylogenetictree which was constructed using Statistical Analysis System computer programme based on genetic distances clearly revealed that all individuals in the first generation gynogen population were clustered into one group,while all the individuals originated from the second-generation gynogen population were joined into another group.