Master of Science (MS)


Plant, Environmental Management and Soil Sciences

Document Type



Twelve virus-tested mericlones were derived from virus-infected 'Beauregard' clones to compare relative effects of viruses and mutations on yield and quality. Virus-tested refers to plants derived from meristem-tips that have been assayed three times with virus sensitive indicator plants Ipomoea aquatic and I. sestosa. The clones represent various selections from 10 production areas in Louisiana, two clones from the foundation seed program at Louisiana State University AgCenter Sweetpotato Research Station, and the industry standard virus-tested B-63 mericlone. Two yield plantings were made in the years 1998 and 1999. Overall, in three of four planting dates, virus-tested mericlones had significant yield increases of 92% to 505% for U.S.#1 over their respective virus-infected clones. Yield increases in three of four plantings ranged from 9% to 1000% for U.S.#1 grade for virus-tested mericlones when compared to their virus-infected clone counterparts. The majority of the tests showed virus-tested mericlones had a higher root and vine weight than virus-infected clones. Virus-tested roots had a significantly redder skin, while virus-infected roots had darker hued flesh and cortex. This has not been previously reported. Comparisons within virus-tested clones did not show any yield differences or differences in color, suggesting clonal variation has a minor affect on general agronomic traits of 'Beauregard' sweetpotato. Ten decamer primers were used in RAPD analysis of the virus-tested mericlones and virus-infected clones. No polymorphisms were found among 29 DNA markers assessed. In summation, data suggests that 'Beauregard' has a relatively stable genome and that variation among clones is mostly a function of virus infection.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Don R. LaBonte