Utilization Of Germplasm Lines With Wild Gossypium Species Consanguinity In Cotton Heterosis

Cotton is the important economic crops and the hybrid cotton has been the main cultivar type in Yangtze River cotton-growing valley in recent years. It is also widely cultivated in Yellow River cotton-growing valley. So widespread of hybrid cotton planting has played a positive role in our country’s cotton production. In this study,4transgenic insect-resistant G hirsutum varieties were used as females and7germplasm lines with wild gossypium species consanguinity were used as males, using an incomplete diallel mating design method, were used to produce28F1hybrids to conduct comparison test for deeply understanding the parents’source and different combied patterns influencing on heterosis and providing theoretical and practical basis for the use of cotton heterosis. Genetic distance of parents and combining ability relationship with cotton yield and fiber quality heterosis were studied and genetic characteristic of good wild fiber quality traits in the background of transgenic cotton was analyzed. The main results were as follows:1. Through analyzing the heterosis of F1population, we could learn that F1population had significantly or high significantly positively mid-parent and over-parent heterosis in cotton yield (CY), lint yield (LY) and boll weight (BW). CY and LY had no significantly and significantly negatively competitive heterosis respectively. P3XP11and P3XP6had significantly competitive heterosis in CY and LY respectively in terms of concrete combinations. Fiber elongation (ELO), fiber uniformity index (UI) and fiber strength (STR) had super-female heterosis and competitive heterosis, micronaire value (MIC) and fiber elongation (ELO) had competitive heterosis. This showed that when transgenic insect-resistant G hirsutum varieties were crossed with germplasm lines with wild gossypium species consanguinity, F1fiber quality did not have advantage over males, but it had significantly advantage over females. Genetic characteristic of good wild fiber quality traits had obvious effects on the improvement of G. hirsutum’s fiber quality and the use of heterosis, while it had little function on improving the yield.2. Though the analysis of general combining ability (GCA) effects and special combining ability (SCA), the main conclusions were drawn as follows:In the4transgenic insect-resistant G hirsutum varieties, E-3109had preferably GCA effects for yield, lint percentage (LP), Lint index (LI), MIC, etc.119-1had preferably GCA effects for UHM and STR, and08-E-3103had highest GCA effects for UHM and UI. In the7germplasm lines with gossypium wild gossypium species consanguinity, LD-697had preferably GCA effects for yield, LP, B/P (boll/number) and MIC, LD699had preferably GCA effects for LP, LI, SI (seed index), UHM, ELO and MIC, DH966had preferably GCA effects for UHM and STR, and DH962had preferably GCA effects for yield. Parents could be used as good candidate for high-yield or high-quality combinations based on the difference of its GCA efforts. GCA was significantly positively correlated with F1all agronomic traits which showed that when formulated combinations, at least one of parents should have high GCA effects. SCA was significantly positively correlated with most of the F1agronomic traits.3. Clustering analysis of11parents based on AG-GD (genetic distance estimated by agronomic traits) and SSR-GD (genetic distance estimated by SSR makers):The amplitude of variation of parents’ AG-GD was2.32to8.2and the average was5.12. The amplitude of variation of parents’ SSR-GD was0.3to0.83and the average was0.6. Two clustering analysis method cluster4females together and7males together respectively which showed that two sets of parents had significant difference in inheritance. AG-GD was significantly positively correlated with SSR-GD and the correlate coefficient was0.29which showed that two clustering analysis method were basic unanimously.4. AG-GD and SSR-GD relationship with heterosis:AG-GD was significantly positively correlated with F1phenotypic of LY, LP, LI and ELO, significantly negatively correlated with UHM, UI, MIC and STR, and significantly positively correlated with F1mid-parent heterosis of ELO, LY, LP and BN. SSR-GD was significantly positively correlated with F1phenotypic values of LI and LY, significantly negatively correlated with UI and mid-parent heterosis of STR. The relationship of genetic distance estimated by on two methods with heterosis did not completely consistent.5. The F1which were formulated by GK19were poor in bollworm resistance, and F1formulated by the119-1、E-3109、08-E-3103were better in bollworm resistance which showed up the typical dominant single-gene genetic characteristics. F1insect resistance was positively correlated with UHM and STR, and negatively correlated with UI, MIC and ELO, but the correlation did not significant.6. Through the comprehensive comparison on28F1, P4×P6was screened which resist bollworm and had excellent yield and quality. Its lint yields was117.86kg/666.7m2and5.15%higher than CK, UHM was30.25mm and7.19%longer than CK, MIC was4.98and10.46%lower than CK, STR was32.15cN/tex and3.07%higher than CK.6 combinations was screened which resist bollworm and had excellent quality including P4×P7, etc. These combinations’UHM were more than32mm, STR were more than32cN/tex, and MIC were less than5.0. So it could be used as materials to cultivate high heterosis combinations.