Construction Of Linkage Genetic Map And QTL Mapping For Plant Height Related Traits Inricinus Commnunis L.

A genetic map was constructed with F2population derived from the cross ofYC2×YF1and the QTLs conferring the plant height related traits were mapped in two F2populations derived from tall, dwarf combinations YC2×YF1and YC1×YF1. The mainresults are as follows:1.1000pairs of SSR primers,381pairs of SRAP primers and480pairs of SSRAPcombination were developed,237,24and27pairs of polymorphic primers were selectedfrom the above three kinds of primers respectively. Totally,288pair of polymorphicprimers plus1ISSR primer and3morphological markers were used to scan the mappingpopulation. The size of PCR products approximately ranged from100~500bp,100~800primers,100~600primers, respectively.2. The genetic map constructed with Mapmaker3.0contained19linkage groups andcovered2751.3cM of genome with a average interval of11.91cM betweene markers. Thenumber of markers each group contained ranged from2to42and the group length rangedfrom11.4cM to499.0cM. The marker density varied from5.7cM per marker on group11to13.7cM per marker on group4. The maximum interval was29.7cM between RCM219and RCM720in group4. RCM855and ISSR836were two co-segragating markers in thesame regions. There still were22gaps(≥20cM) on the map. Consequently, the estimatedgenome size was approximately3370cM, which means this map covers81.6%of thewhole genome of castor.3. The plant height (PH) was significantly and positively correlated with bearingheight of primary raceme (PRH), length of main stem internode (MSIL) and main stemdiameter (MSD) but not with node number of main stem (MSNN), PRH was significantlyand positively correlated with MSNN, MSIL and MSD, MSNN and MSIL wassignificantly and negatively correlated with each other.4. In F2population derived from the cross of YC2×YF1, five, four, six, three and twoQTLs for PH, PRH, MSNN, MSIL and MSD were detected by QTLnetwork2.0, whichexplained45.9%,45.3%,66.1%,55.4%and12.6%of the phenotypic variationrespectively. In F2population derived from the cross of YC1×YF1, three, four, five, one and two QTLsfor the five traits mentioned above were detected, which explained45.9%,45.3%,66.1%,55.4%and12.6%of the phenotypic variation respectively.5. It was concluded that the pleiotropy or linkage between QTLs results in thepositive correlation between PH, PRH and MSIL, the additive effect was the main geneticcomponent of PH, PRH, MSIL and the epistatic effect was the main genetic component ofMSNN and MSD. It suggested that PRH and MSIL should be used to select and predict PHindirectly in the early stage, more MSNN and shorter MSIL should be regarded as thetarget traits for high-yield breeding.