Date of Award

12-2022

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Plant and Environmental Science

Committee Chair/Advisor

Dr. Churamani Khanal

Committee Member

Dr. William Rutter

Committee Member

Dr. John Mueller

Abstract

Meloidogyne enterolobii is an aggressive root-knot nematode (RKN) species that has emerged as a significant pathogen of sweetpotato in the Southeastern US. Meloidogyne enterolobii is spread through the movement of infected ‘seed’ sweetpotatoes used for propagation, and the RKN resistance in commercial sweetpotato cultivars has proven ineffective against this nematode. This has prompted regulatory agencies to impose quarantines on regions infected with M. enterolobii. Sweetpotato storage roots can be rendered unmarketable due to M. enterolobii infection, resulting in potential overall yield loss. Visual detection of RKN in sweetpotato can be unreliable, and further distinguishing M. enterolobii from other RKN species that infect sweetpotato currently relies on molecular tests conducted on individual nematodes. This project had two main objectives aimed at providing the sweetpotato industry with tools to manage and slow the spread of M. enterolobii. For objective 1, a high-throughput survey method was developed to skin batches of sweetpotato storage roots for quick and sensitive detection of M. enterolobii. This method would provide regulators with a protocol to detect M. enterolobii in ‘seed’ sweetpotatoes before they are shipped and planted, thereby avoiding further geographic spread of this nematode. For objective 2, damage caused by M. enterolobii on storage roots of various sweetpotato genotypes was assessed in long-term greenhouse assays. By evaluating the response of resistant germplasm to M. enterolobii infection, vital information can be provided on how these sweetpotato cultivars will perform when planted in a field infested with M. enterolobii. The results from these objectives will provide tools that could help slow the geographic spread of M. enterolobii and mitigate the damage caused by the nematode by assessing M. enterolobii-resistant germplasm within the sweetpotato production industry.

Author ORCID Identifier

0000-0002-0014-4384

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