Location: Crop Genetics and Breeding Research
2022 Annual Report
Objectives
1. Deployment of root-knot nematode resistance in cotton and peanut.
1.A. Determine the economic value of growing nematode-resistant vs. a susceptible cultivar in continuous and rotated peanut.
1.B. Evaluate the economic effect of growing M. incognita-resistant cotton in fields with damaging levels of the nematode.
2. Identify and screen nematode resistant crops that can be grown in rotation with cotton and peanut.
2.A. Identify sources of resistance to Meloidogyne incognita in sorghum that differ from known sources of resistance.
2.B. Identify sorghum cultivars that are poor hosts for Pratylenchus brachyurus and Meloidogyne arenaria.
3. Increased understanding of the interactions between plant-parasitic nematodes and the soil microbiology community and how that contributes to disease.
3.A. Evaluate the interactions of nematode parasitism, the salicylic acid (SA) and jasmonic acid (JA) plant defense pathways, and Fusarium oxysporum f.sp. vasinfectum in the Fusarium wilt disease complex in cotton.
3.B. Investigate the contribution of predatory nematodes in suppressing root-knot nematodes.
3.C. Identify the host and environmental factors that influence the attachment of Pasteuria penetrans spores to Meloidogyne arenaria.
Approach
The long-term goal of our research is to develop integrated approaches for managing plant-parasitic nematodes in cotton and peanut. Host-plant resistance is the most consistent means of reducing yield losses from nematodes. Our research will investigate the most effective deployment of resistance in cotton and peanut for improving yield and economic returns. For sustainable long-term production, farmers cannot rely solely on host-plant resistance for managing plant-parasitic nematodes. Therefore, we will investigate other management options. We will identify crops that can be grown in rotation with cotton and peanut that will reduce population densities of damaging nematodes. Biological control organisms are being marketed for use in cotton and peanut, and they also occur naturally in fields. We will investigate the contribution of predatory nematodes to suppression of root-knot nematodes and the environmental factors that influence the susceptibility of these nematodes to their host-specific bacterial pathogen, Pasteuria penetrans. Nematodes commonly interact synergistically with other plant pathogens to cause greater crop losses. We will investigate how nematodes interact with cotton’s innate defense systems and whether that plays a role in the Fusarium wilt disease complex.
Progress Report
This is a new project that began March 29, 2022 and replaces project 6602-21220-016-000D, "Genetics and Integrated Management of Plant Parasitic Nematodes in Cotton and Peanut".
We planted peanut to keep the root-knot nematode populations up in the field we plan to use to determine the economic value of planting peanut in a crop rotation system. We were unable to initiate the experiment in Fiscal Year (FY) 2022 due to the loss of a critical technician (Objective 1).
We planted nematode-susceptible cotton to keep the root-knot nematode populations up in the field we plan to use to determine the economic value of planting nematode-resistant cotton. We were unable to initiate the experiment in FY 2022 due to the loss of a critical technician (Objective 1). Cotton also was planted in our other field locations so that they would be ready for future experiments as well.
Two greenhouse trials were completed to evaluate the level of nematode reproduction on a collection of sorghum genotypes that have often been used in sorghum breeding (Objective 2).
Seed for most of the sorghum association panel (SAP) has been obtained and will be available for testing beginning in FY 2023 (Objective 2).
Sorghum genotypes with mutations in the candidate resistance genes Sobic.005G055900 and Sobic.005G057700 that putatively impart resistance to M. incognita were obtained, however, we discovered that they also contain other mutations that would confound our study. Therefore, additional breeding and selection is being done to eliminate the undesired mutations. This unexpected work will delay this project by at least one year (Objective 2).
We are building up populations of lesion nematode (Pratylenchus brachyurus) in the greenhouse to start evaluating sorghum for resistance to this nematode next summer (Objective 2).
Efforts are ongoing to identify and test the methods needed to quantify the effects of nematodes and fungi on the SA and JA defense pathways in cotton. We should be ready to begin the study as planned in FY2023 (Objective 3).
Conducted 1st year of within field local adaptation of Pasteuria to its local host. We also were able to complete the 1st year of the between field local adaptation experiment ahead of schedule (Objective 3).
Accomplishments
