| Drought is one of the important factors affecting the growth and yield of wheat.In this experiment,TL-RIL population and its parents were used as materials.Under the condition of 20% PEG-6000 simulated drought and control,the related phenotypic characters were studied,and the variation analysis and correlation analysis were carried out.The drought resistance of wheat seedling was evaluated by principal component analysis and membership function.QTL analysis of drought resistance characters,drought resistance coefficient and D value of 14 wheat seedlings was carried out by using high density genetic map.The main results are as follows:1.Variation analysis and correlation analysis showed that under drought stress,the variation coefficient of total root length was the largest(21.03%),and that of seedling height was the smallest(8.66%).Under normal conditions,the coefficient of variation of root volume was the largest(21.43%)and the coefficient of variation of root number was the smallest(8.29%);under drought conditions,the height of morphological indexes,the maximum root length and the number of roots showed significant or extremely significant positive correlation,and the biomass traits showed significant positive correlation under both treatments.There was significant positive correlation between total root length and root surface area,root volume and root average diameter2.The results of principal component analysis and drought resistance comprehensive evaluation showed that 14 drought resistance related forms could be transformed into 5 comprehensive indicators,and biomass,average root diameter,root surface area root volume and dry weight root shoot ratio could be used as drought resistance identification indicators for wheat seedling drought resistance research.The D values of TL95,TL112,TL155,TL156 and TL175 in RIL population were all higher than 0.7,indicating that they had strong drought resistance.3.QTL analysis showed that 215 QTLs were detected on 21 chromosomes,of which 98 were positive,indicating that the increase effect of QTLs came from the female parent Tainong 18;117 were negative,indicating that the increase effect came from the male parent Linmai 6.The average contribution rate ranged from 0.68% to 19.15%.30 QTLs with the contribution rate of more than 10% were the main QTLs.In the analysis of 145 morphological drought-resistant QTLs,64 QTLs were detected under drought conditions,76 QTLs were detected under normal conditions,and 5 QTLs were detected under two treatments.4.High frequency QTL analysis showed that 25 relatively high frequency QTLs(RHF-QTLs)were detected,with an average contribution rate ranging from 3.15% to 31.26%,and the contribution rate of QDCRv-1D was more than 10%.Among the 16 morphological characters of RHF-QTLs,there are 4 RHF-QTLs specifically expressed,6 non-specific RHF-QTLs stably expressed and 6 stable RHF-QTLs.5.QTL cluster analysis showed that there were 6 QTL clusters formed by 25 RHF-QTLs,which were distributed on chromosome 1D,3A,3B,5D and 6B. |
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