Characterization Of Genotypes Of Wheat And Its Relative Rye Using RAPD Markers

Wheat is one of central provision crops in the world, but among common wheatcultivars there are low genetic diversity own to long-term directional upgrading, whichdeeply limit yield and improvement in quality. In order to improve heterosis of hybridwheat, it is necessary to establish new heterotic group. The study was initially undertakento evaluate the genetic diversity between wheat species and its relative rye as revealed byrandom amplified polymorphic DNA(RAPD), In the study, three common spring wheatcultivars, eighteen winter wheat and three relative rye cultivars introduced from differentregions of china were used for RAPD analysis. Meanwhile, the extraction methodology ofgenomic DNA of wheat was also explored by optimizating the experimental profile andparameters were also optimized , Results were as follows: 1. In the study, the genomic DNA extracted by advanced SDS method could be fullyused for RAPD analysis, furthermore, the method explored was applicable, economical,simple and rapid. 2. To gain a advanced system suitable for RAPD analysis, the experimental profileand parameters were optimized. The protocal improved was as follows: 25μl reactionsystem containing 30ng template, 2.0mmol/L Mg²⁺, 0.6μmol/L primers , Taq polymerase0.75U, 200μmol/L dNTPs. The optimal amplification program was as follows: 5min at 94℃, followed by 94℃for 30s, 37℃for 60s, 72℃for 90s, 40 cycles and final extension timeof 72℃for 7min.In this optimized experiment conditions reproducible results could beobtained. 3. 48 Genotypes were investigated using random amplified polymorphic DNA marker,22 primers was polymorphic. The results were as follows: (1) A total of 142 products wereamplified with 22 primers, of which 94(66.2%)products were found to be polymorphicamong the 24 genotypes, the polymorphic products amplied by each primer ranged from 2to 7, with an average of 4.27. RAPD polymorphism was found to be much higher betweencommon wheat and rye cultivars (66.20%) than in common wheat(43.90%); Amongcommon wheat, RAPD polymorphism was much higher in winter wheat than in springwheat. (2) The 142 polymorphic products were used to calculate genetic distance(GD),Theresult indicated that mean genetic distance was four times larger in rye andcommon(0.5086)than in spring wheat and winter wheat(0.1378). (3) The result of clusteranalysis by using UPGMA method showed that the 24 genotypes were distinctly classifiedinto two groups. Group 1 included all common wheat cultivars, in which spring wheatcultivars were distinctly separated from winter wheat cultivars. Group 2 included all threerye cultivars. It was noted that lines from the same breeding program tend to be grouped inthe same subgroups. It was concluded that common wheat and rye cultivars showed muchhigher genetic diversity within their populations which could be used to diversify thegenetic basis for hybrid wheat breeding and to improve heterosis,It suggested that RAPDmarker could be used to establish wheat heterotic group. 4. RAPD analysis can examine lots of variations. There were twenty-four RAPDcharacteristic markers, which were detected as a group of DNA fingerprints to identify thetwenty-four cultivars. Specific markers were found in five cultivars, They are Yunmai39,Nongda139, Zhongyou9507, Fengkang8 and Yangmai5. These specific bands wereimportant characterization for distinguishing common wheat and rye cultivars. The results as above shown that RAPD marker can be used to analysis DNAfingerprints of wheat, determine genetic diversity and identify heterotic groups of wheat.