Burgeoning demand for sweetpotato [Ipomoea batatas (L.) Lam] is being driven by strong consumer consumption of fries and robust fresh market sales. Acreage has rebounded to meet needs, but increased supply has weighed negatively on fresh market prices, and processing sweetpotato is generally at a low price point. Growers are challenged with increasing production costs and labor is the most expensive input; reducing labor costs through mechanized harvest is critical. Many popular varieties of sweetpotato are highly susceptible to skinning damage and the problems that are associated with exposed root flesh such as rotting, weight loss, and sunken areas. The present study compared methods to assess skinning damage and determine if it is possible to breed for a more skinning resistant variety to aid in further mechanization. A torque wrench was found best at quantifying the amount of force required to cause skinning damage. A two year study of a parent and offspring population using the torque wrench found a heritability estimate of 0.10 on an individual plant basis and a 0.63 heritability on a family basis. It is assumed that an estimate above 0.50 is sufficient to improve a trait and data showed utility using families in breeding scheme, albeit this brings complications. The research also examined genes differentially expressed at skinning injury sites in 2 different environments. Over expression of genes involved in healing may decrease damage that does occur after skinning damage and complement a more durable skin. Consequences of skinning are lessened by curing roots (32° C; 85% relative humidity for 5 days); wound sites are rapidly healed with nominal desiccation. Cyt P450 and Ext, genes associated with periderm formation and wound healing, were found up-regulated in a curing environment compared to skinned sites at ambient outside conditions (conditions varied from approximately 26-30°C, with 50-70% RH ) over multiple time points (2 h, 4 h, and 24 h after skinning). Multiple genes associated with stress were found up-regulated in the ambient conditions. It is hypothesized that selection of genotypes with a more durable skin and enhanced repair mechanisms may further the quest towards mechanized harvest.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-01122015-110335 |
| Date | 20 January 2015 |
| Creators | Legendre, Reeve Daniel |
| Contributors | LaBonte, Don, Arancibia, Ramon, Baisakh, Niranjan, Villordon, Arthur, Smith, Tara |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-01122015-110335/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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