| In the process of breeding new varieties of crops, some excellent crop varieties （or lines） due to high yield, disease resistance and wide adaptability, and as hybrid parents, it has higher combining ability, excellent heritability and other advantages, and derived from many of the widely used value of new varieties, these crop varieties are called Founder parent.Based on yield-related phenotypic analysis, combined with SSR, SNP and DArT marker, the wheat founder parent Fan6and its derivative varieties, intermediate parents and the other local varieties and four founder parents were investigated. Genome-wide scan the wheat founder parents Fan6and its derivative varieties, in order to reveal important choromosome regions and key loci controlling yield traits, and clarifying the genetic effects of these choromosome regions and key loci in derivative offspring, to provide a reference for the use of founder parents and molecular breeding on yield-related traits.1. The traits related to yield phenotypic characteristics of the the wheat founder parent Fan6and its derivatives varieties were investigated. Compared with Sichuan wheat varierties which were in the same period with Fan6, plant height was significantly lower than that of Ya’an Zao, while1000-grain weight were higher than that of Ya’an Zao. Spike length was significantly lower than that of Ya’an Zao, number of spikelets, grain number per spikelet, effective tillers, grain length and grain width were close to those of Ya’an Zao. Complicated derivative varieties of different generations, each trait evolution performed stably, without significant difference. Thus traits which could enhance yield performance of Fan6expressed stably in different derivative varieties, reflecting Fan6had a strong general combining ability on yield traits.2. Though SSR, SNP and DArT marker, genome-wide scan the wheat founder parents Fan6and its derivative varieties, to reveal the specific loci of Fan6specific loci. A total of417pairs of SSR primers related to yield traits were used to amplify62tested materials, of which172were polymorphic, the proportion of polymorphic primers was172/417. The172polymorphic primers amplified185specific loci in Fan6, the frequency ranged of0.051to0.949. A total of118（accounting for63.0%of all polymorphic primers） SSR specific loci in genetic frequency of derivative varieties is equal to or higher than50%. A total of11SSR specific loci （Xwmcl34, Xgwm264b, Xwmc419, Xgwm154, Xwmc657, Xwmc737, Xgpw7812, Xbarc84, Xgwm219, Xbarc1096, Xcfa2257） in four generation offspring, genetic frequency higher than the theoretical genetic proportion. Through the analysis of SNP and DArT, the genetic frequency of7629SNP and658DArT markers in the derivative varieties of Fan6, is higher than50%. Compared to other parent varieties derived from the derivative varieties,85SNP and17DArT markers were reserved in one to four generation derivative varieties of Fan6, and the genetic frequency of51SNP and the10DArT markers in the different derivative generations varieties also higher than the theoretical genetic proportion, indicating the specific loci from Fan6were continually selected.3. Based on molecular marker region analysis, a total of13specific genomic regions of founder parent Fan6ware found, and these regions distributed on chromosome1B,2A,2B,3B,4A,4B,5A,6B,7A and7B. Wherein the four pair of primers1A and chromosome4B are formed xwmc419～xwmc657, xbarc61～xwmc134, and xwmc419～xbarc61covering2.3,6.6and7.5cM, respectively.4. Based on yield-related phenotypic analysis, combined with SSR, SNP and DArT markers, the association anaylsis of specific loci and agronomic traits of the founder parent Fan6were conducted. It was found that the genetic frequency of four SSR loci （Xbarc10, Xgwm526, Xbarc100and Xcfa2170） in Fan6and its derivative varieties equal to or higher than50%, and these loci were closely related with plant height, spike length, spikelet number per spike, and1000-grain weight. Xgwm526was associated with plant height, spikelet number per spike in Xgdm93.3～Xgwm526.2on chromosome2A. Xbarc100was associated with1000-grain weight in Xbarc100-Xgwm156.1on chromosome5A. In addition, there are two specific loci Xgwm614and Xbarc61, reserved in the four derivative generations varieties, were associated with plant height and spike length. In the founder parent Fan6, the SNP specific loci wsnpExrepc6754266164609was significantly associated with grain number per spikelet, and three SNP loci （i.e. wsnpExrepc6644864683704, wsnpRac3939447110214and wsnpRFLContig40764580964） were significantly associated with grain length, and the genetic frequency of these loci in the derivative varieties were greater than50%. The three specific DArT loci （wPt-669297, wPt-7074, wPt-669299） were associated with plant height, effective tillers,1000-grain weight and grain width; and five DArT Loci （i.e. wPt-9124, wPt-3689, wPt-9791, wPt-5037and wPt-1730） were associated with plant height, effective tillers and grain width.5. Forming founder parents had many excellent traits optimized combination. It is difficult to reflect the essential characteristics of one variety which could be used as excellent parent though only a particular aspect or certain aspects. In the study, found the phenotypic characteristics and specific genomic regions of Fan6might play a very important role in becoming the founder parent. |
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