Selection Effect Of Different Breeding Populations And Generations In Cotton

In this study,the basic-material is F1which is combinations of chuang091and KBQS01with excellent characters in regional trail, then the F2population is derived from F1, and the F3-F5breeding populations are built by mixing selection and mixing gather. The year of2012, four breeding populations of F2-F5conducted of comparative experiment between yield and main traits of four different generations populations through experiment using two4X4Latin square design, which in combination of KBQS01by according to conventional breeding methods to select20excellent plants and randomly select30plants in each generation populations, according to inter-contrast method to experiment the second annual planting two types of plant progeny strains line. The main results of this study were as follows:1. The difference of lint yield among F2, F3, F4and F5is not significant, however, the yield of high generation populations is higher than the low generation populations as a whole. The traits of plant height, fruiting branches number, seed index, fiber uniformity index, fiber elongation among different generation populations are not significant. The difference of lint percentage between different generation populations is significant, and lint percentage is the highest in low generation population F2. The difference of boll weight, upper-half mean fiber length and fiber micronaire value among different generation populations is significant, and their maximums are all in the high generation of F5.2. There are big differences among the variation of different plants traits:the variation coefficient of lint yield and boll number per plant is the highest:they are higher than20%; the variation coefficient of fruiting branches number, boll weight, seed index and lint index is middle:they fluctuate between10%-14%; the variation coefficient of plant height, lint percentage, upper-half mean fiber length, fiber uniformity index, fiber micronaire value, fiber elongation, fiber strength, are all less than10%.3. Lint yield between the different generations of offspring plants line the preferred plant were higher than randomly selected among strains of plant progeny strain lines, it means that optimization is effective to the lint yield, but increase the magnitude is not large, however, between the plant of the random selection and the excellent plant of choice of lint yield of progeny strains line low generation of F3:4were significantly lower than lint yield of the high generation of F4:5. Optimization is effective to reduce plant height, raise lint percentage and lint yield, it have little effective to the fruiting branches number and boll weight, in this experiment preferably to the number of bolls per plant have a negative effect. Upper-half mean fiber length, fiber uniformity index, fiber elongation and fiber strength of four quality traits at the average performance of offspring plants strains lines the excellent plant of choice is higher than randomly selected strains line of plant progeny. On the contrary, fiber micronaire value at the average performance of offspring plants strains line the excellent plant of choice is lower than randomly selected strains line of plant progeny, it means that optimization is effective to improve fiber quality.4. The broad heritability of height, boll weight and lint percentage is big, while broad heritability of lint yield, fruiting branches number and number of bolls is small, plant height were suitable for selection in the early generations; boll weight selected in the high-generation selection is more favorable; lint percentage options are likely to yield results between the various generations, the experiment showed that choosing in F4:5generation is most effective; lint yield is more effective chosen in high-generation; the effect of boll number and boll/plant were not obvious chosen in the intergenerational. In addition to uniformity index, five major fiber quality traits were in the generations of F2:3-F5:6, the remaining four broad heritability of traits was relatively large, the average of upper-half mean fiber should be selected in early generations; uniformity index should be selected in the late mid-ideal effects; the fiber micronaire value should choice in the late; fiber elongation selection is ideal in the generation of F3:4; fiber strength should choice in earlier generations, fiber strength chosen in the generation of F3:4is most effective.5. Correlation studies of plant and progeny strains line showed that:the correlation of lint yield, fruiting branches number and boll/plant among generations were not big; boll weight and fiber elongation in the early generations is correlate instability, but relatively stable in the late generations, the effect of choosing in the late generations is ideal.the coefficient of determination of plant height, lint percentage, upper-half mean fiber length and fiber strength is large among the various generations, genetic is stable relatively, effect of selection in the early generations is significant. So does the genetic stability of fiber micronaire value, effect of selection in the the mid-and late is better; genetic stability of uniformity index is poor, vulnerable external environment effect, choice reliability is not big.