Study On Polyploid Technology Of Large Yellow Croaker Induced By Temperature Shock

In this study,we explored the suitable conditions for temperature shock-induced homologous and heterologous(Nibea albiflora)polyploid in large yellow croaker(Larimichthys crocea),and observed the fertilization rate and hatching rate under different induction conditions.The polyploid induction rate was detected by flow cytometry.The optimal induction conditions were selected to carry out the batch induction of polyploidy in large yellow croaker.The transcriptome sequencing technique was used to study the tetraploid of large yellow croaker.Difference in gene expression of diploid fry.The main results are as follows:1.Inducing homologous polyploidy of large yellow croaker.Under the conditions of induction treatment with water temperature of 2℃ and salinity of 20,cold shock treatment was started 3 minutes after inse mination to obtain 100%triploid induction rate,but fertilization rate and hatching rate.Both are lower(less than 5%);after treatment for 2.5 min after inse mination,cold shock treatment for 12 min,triploid rate can reach 89%,fertilization rate and hatching rate can reach 65%and 70%,more suitable for direct batch cultivation of triploid fry.Under the same water temperature and salinity conditions,treatment with cold shock for 12 min at 47 min after inse mination gave two tails(100%)of autotetraploid.2.Under the same water temperature and salinity conditions as above,the allogeneic triploid was induced on the fertilized eggs of the large yellow croaker × Huanggu carp,and the cold shock treatment was started for 12 min at 2.5 min after inse mination.The fertilization rate was 20%,and the hatching rate was 2%,triploid rate 90%.3.Using the optimal conditions obtained from the above experiments,the homologous polyploid batch induction of large yellow croaker was carried out until 3 months old,and the homologous triploid fry 20,000 tails(triploid rate 63%),homology Ⅳ 2500 ploidy fry(tetraploid rate 3%).It is still in the process of breeding..4.Using transcriptome sequencing technology to analyze the difference in autotetraploid and diploid gene expression between large yellow croaker,33 genes that were up-regulated in tetraploid and 24 down-regulated in tetraploid were obtained.The up-regulated genes that have been labeled are associated with disease resistance,and both of the labeled down-regulated genes are associated with metabolism.