| Barley is one of the oldest crops. Its sown area, after maize, rice and wheat, ranks forth in the world. Barley contents various nutritional components, such as human necessary amino acids and minerals. It has been used for human food, animal feed and malting brewing, to mention a few. And barley is rich in functional compounds:(3-glucan, resistant starch, flavonoids, γ-aminotutyric acid and so on. Because of high nutritional value and health care function, barley is becoming more and more popular in human food. The functional compounds of barley are genetically controlled by polygene and easily influenced by environment, so it is very difficult for traditional breeding methods to cultivate new barley varieties, which are rich in functional components. The development of molecular biology has been provided theoretical basis and realistic significance for these challenging problems.In this study, we used a DH population derived from the cross between Steptoe and Morex. And SSR and SRAP, the two types of molecular markers, were used for constructing genetic map. The two parents have significant differences in agronomic traits and flavonoids, GABA contents. In this study, we investigated these traits and mapped for QTL. The main results as fellows:1.525markers were screened for polymorphism between parents of the DH population.133informative primers were used for genotype between the mapping population.181loci were used for constructing genetic map. The map we constructed in this study includes9linkage groups and171loci (69SRAP loci,102SSR loci) were assigned to9linkage groups, which were mapped on corresponding chromosomes by SSR markers with known chromosomal locations in barley. The map covered1424.2cM with a mean density of8.33cM per locus. 2.181loci were ananlysed with chi-square test. According to the Mendelian separation ratio(1:1),32loci performed partial separation(P<0.05). Among these loci,7of32were significant partial separation(P<0.01) and all of them were SRAP markers.20loci skewed towards the female parent Steptoe. Each chromosome had the partial separation sites. And3segregation distortion regions (SDRs) were found on2H、4H and5H, respectively.3. The Windows QTL Cartographer2.5was used for QTL analysis. And the main method used in this study was composite interval mapping (CIM). The QTL with LOD value beyond2.5were retained as the effective QTL only.24QTL of agronomic traits have been found.3QTL for plant height were located on3H, the highest phenotypic variance was20.03%.5QTL for main spike length were found. And two of them with the phenotypic variances:36.8%and46.11%, located on3H.3QTL for grain number of main spike were found:explained14.14%、15.05%and16.96%phenotypic variance, respecttively. One located on2H and two located on3H.6QTL influenced tiller number were found. And the two QTL with bigger contribution rates located on2H, with17.11%and21.87%phenotypic variance. For thousand grain weight,3QTL were found, which located on3H、5H and7H, respectively. There was only one QTL for maturity, located on2H, and explained20.14%phenotypic variance.Only one QTL for GAB A content was detected in the experimental field of Ya’an, which located on1H, and it explained8.78%phenotypic variance. The contribution rates of additive was negative, indicating that the effective gene from male parent Morex.Three QTLs for flavonoids content were detected in the experimental field of Ya’an: located on chromosome2H,3H and6H, respectively.3QTLs for flavonoids content were detected in Chengdu (3.2):one on5H and two located on3H. The phenotypic variance from5.83%to8.84%, and all of them were minor QTLs. |
PDF Full Text Request