The Research Of Bt Protein Expression And Fiber Quality In Genotic Population Of Bt Transgenic Cotton

Helicoverpa armigera is the main pest in the growth process of cotton,which damages the whole growth period of cotton from seedling stage to wadding stage.In the past 20 years,the emergence and application of transgenic Bt cotton has effectively restricted the hazard of cotton bollworm and reduced the use of chemical pesticide preparations,bringing significant social and economic benefits to the country,so breeding high-resistance,high-yield,high-quality insect-resistant cotton has gradually become the focus of breeding work.With the application of insect-resistant cotton,it has been found that the insect resistance of insect-resistant cotton has a difference in temporal and spatial expression.It is not conducive to the application of cotton bollworm,and it is not conducive to the breeding of transgenic cotton varieties.In this study,the segregation progeny constructed from high-quality transgenic cotton varieties were used as materials.We investigated the insect resistance performance,yield and quality traits of the progeny,and correlation analysis was carried out to explore the relationship between insect resistance and yield and quality traits of insect-resistant cotton,providing a theoretical basis for breeding the high-yield and high-quality varieties.The main findings are as follows:1.The Bt gene was detected in the F₂ progeny of the insect-resistant hybrid cotton genetic population,and the results that the Bt gene was missing during heredity.The PCR test and kanamycin test are fairly similar but not exactly the same,and screen out insect-resistance cotton to build F_2:3progeny;2.Statistical analysis of F_2:3 progeny bioassay of the F_2:3 progeny of the insect-resistant hybrid cotton genetic population,and the results that the insect-resistance of the population was separated.According to the mortality rate of cotton bollworm larvae in F_2:3 generation:73 of the materials resistance grades were“high resistance”,846 materials resistance grades were“resistance”,8 materials resistance grades were“low resistance”,and 6 materials resistance levels are"sensation";3.The Bt protein content in different tissues and organs of F_2:3 generation in cotton seedling stage,bud stage and boll stage were determined,and the results that there was no correlation between Bt protein expression and the spatial and temporal expression different of different materials.The time difference expression results were:bud stage>seedling stage>bell stage;spatial difference expression results were:vegetative organs>reproductive organs;4.The correlation coefficient between larval mortality and Bt protein content in bud stage,which showed a very significant positive correlation.The results showed that the higher the Bt protein content,the higher the insecticidal resistance of insect-resistant cotton,the better the insect resistance.According Bt protein expression to judgment insect-resistance in breeding;5.At the same time,the correlation between Bt protein content,fiber quality and yield traits of F_2:3progeny of insect-resistant cotton hybrids was analyzed.There was no significant correlation in the analysis results,indicating that the Bt protein content of transgenic cotton did not affect the fiber quality and yield of cotton.Statistical fiber quality and yield trait results,combining with Bt protein content to screen the progeny,coming to a conclusion that L-76 and L-78 were high-resistance,high-yield,high-quality materials.In this experiment,the detection and analysis of insect resistance,Bt protein expression and yield with fiber quality in F₂ and F_2:3 progeny of Bt cotton,provides help for the breeding,variety certificatio and cultivar popularization in Bt cotton.