Using The " Immortalized F₂Population " Of Cotton Study Heterosis Of The Main Breeding Target

With the increase of the pursuit of natural green products, more and more demand for cotton. Yield be imperative, hybrid cotton can improve yield of cotton. With the introduction of molecular techniques, theory development and utilization of Cotton Heterosis, genetic mechanism of Cotton Heterosis will be more and more clearly, the use of heterosis will have greater development.To study the genetic basis of interaction heterosis in cotton, an immortalized F2population of98cross was constructed by intercrossing recombinant inbred lines derived from a cross between the Upland Cotton variety sGK9708and a high strength G. hirsutum line0-153(sGK9708×0-153). Thirteen agronomic and fiber quality traits and heterosis performance were evaluated through three environments.The results were summarized as following:1. The "immortalized F2" population were successfully constructed by randomly intermitting the196RILs derived from the cross of sGK9708x0-153. It contains98combination..2. The"immortalized F2" population contained diverse variations. And transgressive segregation was observed in the current study. Each character heterosis performance is obviously.3. Calculating the average value of the mid parent heterosis On13characters under three environment, average heterosis of lint yield per plant is up to24.39%, the average heterosis of seed cotton yield is21.66%. Yield component factors single boll weight is9.19%. Boll number per plant is8.04%, Lint percentage2.84%. Fiber length, strength, micronaire value, average heterosis regularity is large in all fiber quality traits, but the average heterosis of elongation was negative.4. In three environmental place the competitive advantage of the plant lint yield was an average of17.35%. The "immortalized F2" population of this experiment has aconsiderable competitive advantage, It can be directly used in production..5. The result of correlation analysis showed lint yield per plant and plant height, branch number, boll weight, lint per centage and seed cotton had highly significant and positive correlation. It had significant and positive correlation with fiber length, fiber micronair and fiber uniformity, but no sighnificant correlation between lint fiber strength and fiber elongation.6. Genetic analysis was conducted on cotton phenotypic traits, The results showed that main effects for cotton yield were most significant among which epistasis effects of additive×additive, dominance effects and dominance effects×environments.7.The13traits of the "immortalized F2" population variance analysis, results show, each character between groups, between different regions, different traits and between different regions of the interaction showed significant differences.8. The "immortalized F2" population of yield characters or fiber quality has many excellent combination. Combining the yield and fiber quality traits, only combination MBR150*MBR149showed obvious competitive advantage at the same time than the production control. The results show that the cotton yield and fiber quality traits in combination, to achieve both high yield and high quality combination is not easy to achieve.