| Jackfruit cultivation has a long history in China from a thousand years ago, especially on Hainan Island. Numerous seeding germplasm resources of Jackfruit is scattered distribution on the entire Hainan Island with abundant genetic diversity, which contains rich resources of desirable traits and are hence worthy of exploitation. However, there is no research on the genetic diversity and genetic relationship of jackfruit of Hainan Island. Based on random sampling of jackfruit on Hainan Island, this study on the genetic relationship and genetic diversity of 186 samples of jackfruit, which consisted of 156 samples of Hainan Island, 2 samples of Malaysia, 4 samples of Cambodia, 2 samples of Vietnam, and 3 samples of cempedak (Artocarpus integer (Thunb.) Merr), 1 samples of breadfruit (Artocarpus altilis(Parkinson) Fosberg),was carried out to use SRAP and SCOT molecular markers by the total DNA extraction and PCR reaction system optimization, which provides the basis material for the future orientation breeding and new cultivars breeding and better for the development and utilization of germplasm. The results of the study summarized as follows:(1) Comparative study showed that it can isolated high-quality genomic DNA by using 2% CTAB buffer solution containing 4% ?-mercaptoethanol and 12.5 mmol/L borax for twice extraction, and then by using 1/2 volume absolute ethyl alcohol and 1/2 volume 4 mol/L LiCl to make the RNA precipitation.(2) The concentration of Mg2+ for SCoT-PCR reaction was 2.0 mol/L, that for dNTPs,Taq DNA polymerase, primer, template DNA, and the annealing temperature were 0.2 mol/L,1 U, 0.375 mol/L, 10 ng and 48.2 ? respectively.(3) A total of 1174 bands was obtained by 32 pairs of SRAP primers, 36.69 bands per pair in average, the average percentage of polymorphic bands was 98.72%. Genetic similarity coefficients were changed from 0.6753 to 0.9067 analyzed by NTSYS cluster analysis software. The UPGMA dendrogram implied that the 168 samples could be divided into three groups based on genetic coefficient 0.7345, and the third groups could be divided into twelve subgroups.(4) A total of 266 bands was obtained by 15 SCoT primers, 17.73 bands per pair in average, the average percentage of polymorphic bands was 97.72%. Genetic similarity coefficients were changed from 0.6534 to 0.9110 analyzed by NTSYS cluster analysis software. The UPGMA dendrogram implied that the 168 samples could be divided into three groups based on genetic coefficient 0.7406, and the third groups could be divided into ten subgroups.(5) According to results of two molecular markers, it indicated three aspects as followed.Firstly, 168 samples were clustered by jackfruit, cempedak and breadfruit. Then, jackfruit from the same geographical provenance showed a close phylogenetic relationship,and samples from abroad and domestic showed a slim distant phylogenetic relationship. Lastly,the correlation between genetic distance and geographic distance of jackfruit from different localities of Hainan Island.The genetic correlation of each sample from the same localities of Hainan Island is not only significant affected by geographical distance but also the samples themselves. There are different degrees of cross-clustering between the samples.The genetic relationship of the most germplasm in Chengmai area of Hainan Island are near with each other, and near relationship with that of South Central Hainan island which include Qiongzhong, Baoting, Wuzhishan. There is also certain genetic relationship between the germplasm in Chengmai Haikou, Ding'an, Wanning and Qionghai areas. |
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