| Summary: | 碩士 === 中國文化大學 === 生物科技研究所 === 87 === Abstract
In Taiwan, sweet potato can be grown in all seasons. Cutting propagation is the most popular method for most farms. However, it was found that successive cutting for several generations from the same varietal clone tended to lower the yield of root tuber and generally the root tuber became to get smaller. In this study, we are interesting to know whether the above phenomenon is associated with genomic variations in different cutting generations.
Two cultivars, Tainung 57 (TN 57) and Tainung 66 (TN 66) were used for this study. Original shoots of each cultivar were derived from a micropropagated shoot in vitro. Random amplification polymorphic DNA (RADP) derived from arbitrarily primed polymerase chain reaction (AP-PCR) was used as a tool for detecting genetic variations in plants from successive cutting generations and cuttings grown under different nitric treatment.
A total of 35 random primers were examined on TN57 and TN66 to see if there was any polymorphism among sprout, primary leaf and mature leaf. Seven primers, which had the capacity of revealing the differences among different tissue DNAs, were further served for this study. It was found that all these seven primers were also able to detect the differences in clones derived from different cutting generations as well as cutting clones grown under different nitric managements. Four polymorphic bands were cloned for sequencing. In comparison with sequences in Gene bank (GenBank and EMBL) it was noted that one might associated with mitochondria gene, another had the similarity with Cytosolic Cu/Zn-superoxide dismutase (Cu/Zn-SOD), the third showed the similarity with retrotransposable like-element and the other was similar to Arabidopsis genomic sequence.
Southern hybridization also indicated that degree of methylation might also involved for the genomic variation in differrnt cutting generations and nitric treatments.
Results from this study indicate that Genomic variations tend to occur among different cutting generations. Therefore, cutting propagation should be used cautions.
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