Marker Assisted Selection And Dissection Of Lodging And Preharvest Sprouting Resistance In Annong 0711

Marker-assisted selection（MAS） is a breeding method that cans combinate the phenotype and genotype selection in the process of crop breeding, realizing the integration of biotechnology and traditional breeding method. MAS can effectively overcome some disadvantages of conventional breeding, with higher breeding efficiency and shorter breeding period, and has been used widely on crop traits improvement. The goal of wheat production is to catch high and stable yield. However, preharvest sprouting and lodging are the important factors that reduce the stability of wheat production, which are greatly influenced by environmental factors and are hard to control, relying mainly on varieties resistance itself. The purpose of this study is to breed a new wheat line with high preharvest sprouting resistance by MAS method for the south area of Huanghuai River. The preliminary analysis of genetic mechanism of lodging resistance and yield related traits for new wheat line has been carried on. The major results are as followed:1. Annong0711 was breeded by MAS and traditional breeding method. Annong0711 containing Sprouting resistance genes from parents Bainong64（6BL） and Aizao64（6AS）, showing better sprouting resistance.The results of association analysis show that the pyramid of excellent allelic variation type on chromosomes 2BS,4DS,5A,5DL,6BL and 7DS of the three parents enhance the stem sthrength of Annong 0711 which has good lodging. Linkage analysis show that there was a main QTL on chromosome 5A associated with stem strength. Annong 0711 exist cytokinin oxidase gene Tackx4 excellent allelic variation type, which usually contain higher flag leaf chlorophyll content and grain weight, finally to increase production. A preliminary analysis of the belt type is A factor which influence the production of Annong0711.2. The 42 marker loci were detected by association analysis method in three enviroments（2012, 2013 and 2012 year）, and located almostly on all wheat chromosomes（except 1 D and 6 D）,and were significantly positively correlated with stem strength. Among them, in addition to the marker loci on 3AS, 4AL and7 AL, the rest of the 39 marker loci were detected in at least two environments. The marker loci which located on chromosome 2BS, 2DL, 4DS, 5A, 5BL, 5DL, 6BL and7 DS can be detected in three environments simutaneously, and explained the phenotypic variation of 5.77 18.47%. Marker loci locatedi on 2BS（wmc83）,2DL（gwm539）,5A（barc358）,5BL（barc59） and 6BL（barc134） all have higher phenotypic variation（above 8%） in three environments, among them maker locus located on 2BS（wmc83） achieves a significant level（P < 0.01） of phenotypic variation in three environments. The eight stable excellent marker loci were choosed to carry on allelic variation analysis, including wmc83-2BS,wmc539-2DL,wmc48-4DS,barc358-5A,barc59-5BL,barc322-5DL,barc134-6BL and barc352-7DS. As result, 15 allelic types were found have a positive phenotypic effect stem strength, and allelic types of wmc83-A110（0.02）, gwm539-A120（0.11）,wmc48-A122（0.14）, barc134-A194（0.40） and barc352-A234（0.92） have higher positive phenotypic effect, with the values are: 0.8037, 0.2600, 0.3813, 0.2743, 0.4767.In this study, when compared the cultivars of different stem strength, the result show that with the increase of yield strength, the positive allelic type number is on the rise.3. The QTL linkage analysis were done based on Annong 0711 and Henong 825 F₂ segregation population,and etght QTL associated with stem strength were detected, located on chromosomes 2B、5A、5B、5D、7A �'� 7B, and explained 1.33%–9.78% of the phenotypic variation in srem strength.Among them, QSS.ahau-5A-2、QSS.ahau-5B-1 and QSS.ahau-7A three QTL explained higher phenotypic variation in srem strength, the values are 9.78%, 7.34% and 5.41% respectively.There were 6 QTL been detected on the fifth homologous group, explained 24.35% of the phenotypic variation totally. QSS.ahau-5A-2, QSS.ahau-5B-1 was verified in 675 F₂ separation population, and QSS.ahau-5A-2 can explained 21.18% of the phenotypic variation in srem strength, and the adjacent marker is barc136（3 c M）. Four marker loci were detected on on chromosome 5A associated with stem strength, including barc117,barc207,barc1 and barc358,among them barc358 achieves a significant level（P < 0.01） of phenotypic variation in three environments, explained the phenotypic variation of 14.36%-18.45%.and It is speculated that there was a main QTL associated with stem strength located by comparing the results of QTL mapping and association analyss.4. Grain weight was significantly correlated with chlorophyll content of the flag leaf at 5¹5 days after anthesis（DAA）. Copy number variations（CNV） at the Tackx4 locus were first identified by the primer pair T19-20 and significantly correlated with both two traits. The locus contained at least three copies of Tackx4（Tackx4-1, Tackx4-2, and Tackx4-3）. Some minor mutations also occurred in the intron between these copies. The copy numbers of Tackx4 varied among genotypes; Jing411 had genotype A（Tackx4-1/Tackx4-2） while Hongmangchun 21 had the null genotype（genotype B）. The leaf chlorophyll content and grain weight were higher in genotype-A lines than in genotype-B lines. A linkage analysis indicated Tackx4 was on chromosome 3AL and co-segregating with a major quantitative trait locus（QTL） for leaf chlorophyll content and grain weight. This QTL could explain 8.9²2.3%. This effect of CNV of Tackx4 on the two traits was further validated among 82 cultivars of wheat under varied environments.