Field assessment and diversity panel screening of lima bean host resistance to root-knot nematode
| Author(s) | Traverso, Eboni R. | |
| Date Accessioned | 2023-10-09T17:01:19Z | |
| Date Available | 2023-10-09T17:01:19Z | |
| Publication Date | 2023 | |
| SWORD Update | 2023-09-20T19:18:25Z | |
| Abstract | Lima beans (Phaseolus lunatus) are a key crop in Delaware’s processing vegetable industry. Root-knot nematode (RKN; Meloidogyne spp.) feeding reduces lima bean yield potential by extreme galling of root systems, which severely disrupts water and nutrient uptake, resulting in considerable economic damage. Durable resistance to RKN is the most practical and effective management strategy for RKN but commercial availability is limited in lima beans. A significant aim of the UD Lima Bean Breeding program is to introduce lines with root knot nematode resistance into the commercial market to improve production profitability. Three advanced lines from the program were evaluated for resistance traits and yield potential in an inoculated field trial, along with the commercial standards, ‘Cypress’ and ‘C-elite Select’. All experimental varieties had reduced galling (p < 0.0001) and reproduction (p < 0.0003) compared to the commercial variety ‘Cypress’, and DE1306635 showed significantly higher yield than any of the other varieties (p < 0.0001). All three experimental varieties, particularly DE1306635, are promising in their potential to become established in the commercial market. ☐ To identify novel sources of resistance in the lima bean genome, 256 lima bean inbred lines from the USDA collection, the UD Lima Bean Breeding Program, various commercial seed distributors, and individual accessions from around the world were selected to evaluate RKN resistance. In greenhouse conetainer trials, individual 10- day-old lima bean plants were inoculated with 500 freshly extracted RKN secondstage juveniles, grown for 6-8 weeks, and root systems were evaluated for galling by visual examination. From this panel, 50 large- and small-seeded lima bean accessions with the lowest gall ratings, 5 high-gall controls, and 5 commercial standards, were selected for further screening in field and greenhouse trials. An inoculated trial was established in a field with a history of RKN. Plants were monitored for nine weeks, then destructively sampled for data collection. In addition to root galling, in-field reproduction was assessed by counting the number of egg masses in the root tissues after staining with erioglaucine. Lima bean accession had an effect on RKN galling (p < 0.0001) and reproduction (p < 0.0001). The 60 lines were then screened in a greenhouse conetainer trial to confirm field observations. Root galling and nematode reproduction were assessed approximately nine weeks after inoculation. As in field trials, RKN reproduction (p < 0.0001) was affected by lima bean accession, though effects on galling were more variable (p = 0.0017 to 0.02). Thirteen accessions were recognized in both field and greenhouse screening and are the top candidates for integration into the breeding program. | |
| Advisor | Koehler, Alyssa M. | |
| Degree | M.S. | |
| Program | University of Delaware, Microbiology Graduate Program | |
| DOI | https://doi.org/10.58088/hb95-xr23 | |
| Unique Identifier | 1418843808 | |
| URL | https://udspace.udel.edu/handle/19716/33404 | |
| Language | en | |
| Publisher | University of Delaware | |
| URI | https://login.udel.idm.oclc.org/login?url=https://www.proquest.com/dissertations-theses/field-assessment-diversity-panel-screening-lima/docview/2867896330/se-2?accountid=10457 | |
| Keywords | Host resistance | |
| Keywords | Meloidogyne incognita | |
| Keywords | Root-knot nematode | |
| Keywords | Phaseolus lunatus | |
| Keywords | Plant breeding | |
| Title | Field assessment and diversity panel screening of lima bean host resistance to root-knot nematode | |
| Type | Thesis |