| Bananas(Musa spp.) is one of the major tropical and subtropical crops in the world. Despite the importance of banana in the international trade and comerce, little is known of its genetic system. Contrast to other crops such as rice and maize, there are fewer molecular researches on banana. In this study, twenty-four banana germplasm materials come from different countries and regions were surveyed by RAPD analysis. The results showed as follows : 1 . Using the improved methods of SDS and CTAB , high purity DNAwas obtained from half expanded leaves which had been kept in adarkened chamber for two days .2. Through optimal experiments, the best amplification system of RAPD analysis is set up ,that is : 94℃ initial denaturation for 4min, 40 cycles of 94℃ for 60s, 37℃ for 60s, 72℃ for 105s, and 72 ℃ for 10min. The 25 ul reaction mixture contained 20~50ng template DNA, 200umol/L dNTP, 2.0mmol/L Mg2+, 0.3umol/L primer, 2.5ul 10xEx-Taq polymerase buffer, and 1U of Ex-Taq polymerase .3. Based on UPGMA cluster analysis of DNA bands which were amplified with eighteen RAPD primers , the molecular dendrogram of twenty-four banana germplasm materials were constructed . According to the gendrgram , the twenty-four germplasm materials were assigned to three major clusters . The first cluster included twenty genotypes, the second included three and the other only had one, that is Guangxijijiao(Longyajiao type) . The first cluster could be divided into five sub-groups : I, II , III , IV and V.4. The two-primer RAPD was used to access the relationship of three bananas genotypes from Brazil. The similarity coefficient between Baxibianzhong and Baxixiangjiao obtained from two-primer RAPD was 0.5714 , the low similarity indicated that it is impossible that Baxibianzhong was derived from Baxixiangjiao . The comparison of polymorphism amplified with single-primer and two-primer in three genotypes showed that the two-primer RAPD could produce more polymorphic fragments than the single-primer RAPD .
|
PDF Full Text Request