| Crop yield, quality traits, sharp eyespot and Fusarium head blight in wheat are usually controlled by quantitative trait loci, cloning and using these genes are based on identification and mapping their QTLs. Some linkage populations (F2, BC1, DH and RILs), have complex genetic background, difficult to identify the effect of independent quantitative trait loci and map these loci on the chromosome. In order to improve this situation, some researchers are proposed to construct chromosome segment substitution lines (CSSLs). CSSLs refer to the import of the department donor parent chromosome fragments in a near-isogenic with the same genetic background. Thus, complex traits can be decomposed into a single Mendelian factor, and these advantages pay the researchers’attention. Wheat solid stem, plant height, spike length, spikelets number per spike, sharp eyespot and other important agronomic traits are quantitative traits, studying them is of great importance for wheat breeding. In our study, through the continuous backcrossing and marker analysis strategy, we construct the chromosome segment substitution lines covering the wheat genome-wide; and numbers of QTLs were detected with the use of BC1F1 population, including solid stem, plant height, spike length, spikelets number per spike, sharp eyespot and other important agronomic traits. The main research results are as follows:A total of 831 SSR markers was used for screening polymorphism in two parents. Finally, 178 polymorphic markers were used for population analysis, with the polymorphic rate of 21.4%. Genotype analysis of introgressed segments on 44 BC2F1 plants were conducted, it was found that the donor genotype proportions (DGP) within BC2 population covered 16%-38%, with an average of 27.59%; The total length of introgressed segments (TLIS) ranged from 281.44 cM to 677.22 cM with the average of 485.36 cM; the number of introgressed segments (MS) was ranged from 11 to 23 with the average of 16, so that the average length of introgressed segments (AIS) was ranged from 19.24 cM to 42.36 cM with the average of 17.28 cM. Finally, the recipient genome content (RGC) was calculated. The RGC vaule of each individual in BC2 generation range from 77.38% to 93.45% with the average of 85.23%, which was closed to the theoretical value of 87.5%. The result of BC2 population would lay the foundation and provide useful information for the subsequent phenotype investigation.In 282 BC1F1 lines, the analysis of twelve important agronomic traits showed that eight of them have reached a significant level except the outer diameter of the first section, second section between the outer diameter, spike length and number of spikelets; The coefficient of variation in BC1F1 population ranged from 6.7% to 24.6%; The correlation analysis between the first node and the second node culm traits suggested that there are significant negative correlation between outer diameter of the first and second node culms and thickness to diameter ratio, inner diameter of the first and second node culms has a significantly negative correlations with wall thickness and thickness to diameter ratio, the rest of the traits showed a significant positive correlation between each other.With the use of ANOVA method in BC1F1 population, twelve QTLs were detected linked with solid stem, plant height, spike length and number of spikelets. Of them, including three solid stem QTLs, four plant height QTLs, four spike length QTLs and one sharp eyespot QTL. The phenotypic contribution rate of 12 loci was ranged from 3.32% to 12.63%. Due to the construction of CSSLs is just beginning and the population we used is still segregating, so these results need further verification. The purposes of our study is designed to provide objective traits for future research. |
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