Source: TEXAS A&M UNIVERSITY submitted to NRP
MANAGEMENT OF COTTON AND PEANUT DISEASES IN THE SOUTHERN HIGH PLAINS OF TEXAS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1012424
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Apr 3, 2017
Project End Date
Feb 1, 2022
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
TEXAS A&M UNIVERSITY
750 AGRONOMY RD STE 2701
COLLEGE STATION,TX 77843-0001
Performing Department
Lubbock-TAMU Agr Res Cntr
Non Technical Summary
Diseases of cotton in this region that cause substantial yield losses on a yearly basis are Verticillium wilt and root-knot nematodes. Bacterial blight is capable of causing significant losses sporadically if not managed. Reniform nematode and seedling diseases can also cause losses if not managed. For peanuts, the most important disease problem is pod rot, and the hardest to control is Pythium pod rot. This project is designed to investigate strategies or assist in germplasm development that will minimize losses to these plant pathogens. A large part of the program involves evaluating commercial cotton varieties in multiple producer fields to root-knot nematodes and Verticillium wilt. A field trial is also conducted on cotton variety responses to bacterial blight. The results of these trials are made available to producers, consultants, industry, and university/extension people. In addition, a considerable amount of time is spent in screening germplasm for university cotton breeders and industry in inoculated greenhouse trials. This work provides information to cotton breeders, so that ultimately they bring forward more disease resistance in their releases.Cultural management of soil-borne diseases can have more impact than any varieties or chemicals, however they can also be the most difficult to examine in a research setting. I am fortunate to have two sites where cultural management effects can be studied on large plots over sufficient years to draw sound conclusions. At the Helms farm (infested with Verticillium dahliae), research is conducted on a 120-acre circle which includes crop rotations with cotton, sorghum, and wheat; cover crops versus none; tillage effects (conventional versus minimum); and irrigation rate. This systems trial is typically conducted for at least 4 years before changing the research focus, and involves interactions between scientists specializing in plant pathology, irrigation engineering, cropping systems, and soil nutrients. The effect of crop rotations before disease builds up was previously quantified; the focus is now on the effects of crop rotation after the pathogen is already present in the soil at adequate levels for significant disease. Irrigation rate effects on disease and its consequences for yield are also being studied. The tillage system experiment is fairly recent, and the full impact of the minimum tillage/flat ground system on disease and yield is still to be determined. Prior to 2016, there was a yield detriment to using the flat ground/minimum tillage treatment, however, in 2016, which was very conducive to disease, it appeared to reduce yield losses due to Verticillium wilt, at least in some crop rotations. Our understanding of how all the pieces of crop rotation/minimum tillage/irrigation rate combine to result in yield benefits is still evolving. It will require more years of measuring disease/yield to fully understand the impact and make appropriate recommendations. Similar work is being conducted at the AGCARES circle which is naturally infested with root-knot nematode, though only with crop rotation with cotton and wheat compared to continuous cotton, and irrigation rate. Previous work at this site has investigated crop rotation with sorghum and cotton or peanut and cotton; and also the impact of varieties that are susceptible, partially resistant, or highly resistant to root-knot nematodes. Currently, rotation with wheat appears to have tremendous impact on root-knot nematode densities, to the point where it may be unnecessary to use varieties with resistance to root-knot nematode. However, the rotation work needs to be coupled with irrigation rate. Work several decades ago on this wheat/cotton rotation was not as economically favorable to cotton yields than continuous cotton. There was more water available for irrigation when continuous cotton was so favorable economically. As pumping capacities have declined, rotation with crops like wheat, that allow rainfall captured during the growing season to mostly remain in the field, have changed the yield dynamic. The interaction between pumping capacity/crop rotation/ and root-knot nematode needs to be better characterized so that producers can understand what might be most effective for their circumstances.Chemicals have always played some role in disease management. Seedling diseaes caused by Rhizoctonia solani and Pythium ultimum are very well controlled by using some of the superb seed treatment fungicides now available. New products or product combinations need to be evaluated to determine the more favorable ones for this region. Seed treatment products to manage root-knot and reniform nematodes are now more utilized than other types of chemical treatments. However, it can be very difficult to show adequate control in the relatively dry conditions that are typical for the Southern High Plains of Texas. Products that are efficacious in other states often show much less activity here, so it is important to test experimental materials, that will become the labeled products of tomorrow, as well as existing labeled products that producers must make decisions on. In our program, we cooperate with anyone who has a product that they think will control nematodes. Products that are highly speculative will be tested in greenhouse trials, and those that have shown nematicidal activity will be field tested in small plots. Labeled products will be tested in producer fields, and combined with different varieties, to see if there is a bigger response with susceptible or partially nematode resistant varieties. In short, any management tactic that may improve cotton yields in the presence of diseases of this region are examined for their potential benefits.Peanut diseases can also be important to the economic return of peanuts in this region. The most important disease problem in peanut is pod rot. Fungicides are the primary method of handling pod rot, however, they have generally given only limited control and at great expense when pod rot is caused by Pythium (primarily P. myriotylum). The efforts to control pod rot more effectively are primarily directed at ways to apply labeled fungicides, that improve the control of labeled products (metalaxyl or axystrobin).
Animal Health Component
100%
Research Effort Categories
Basic
0%
Applied
100%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2121710112035%
2121830116065%
Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1710 - Upland cotton; 1830 - Peanut;

Field Of Science
1120 - Nematology; 1160 - Pathology;
Goals / Objectives
The number one goal of this project is to improve disease resistance within cotton. That includes resistance to bacterial blight caused by Xanthomonas citri subsp. malvacearum; Verticillium wilt caused by Verticillium dahliae; and root-knot nematode, caused by Meloidogyne incognita. This goal also includes working with both Texas A&M cotton breeders and with industry cotton breeders. Finally this goal includes evaluation of most commercial cotton and communication of the relative strengths or weaknesses to producers, consultants, and agribusiness professionals. The second goal is to investigate the impact of cultural practices on management of cotton diseases. Three practices that are specifically covered in this project are crop rotation, tillage practices and irrigation rate. This reseach will primarily be conducted jointly with other Texas A&M scientists on large scale plots and involve trials conducted over at least three years. The third goal is to investigate the impact of chemical and biological projects, experimentals or labeled products, on diseases of cotton and peanuts in the Southern High Plains region. This primarily involves working with agrichemical companies such as BASF, Bayer CropSciences, Adama, Syngenta, etc. to test their products.
Project Methods
Verticillium wilt-Germplasm received from Dr. Jane Dever, is screened in the greenhouse for resistance to this disease. Seedlings are grown to the 4-leaf stage and then conidia of V. dahliae which is produced on potato dextrose agar for 5 days is injected (10 x 106/ml) into the stem. Symptoms begin to appear about 7 days later and plants are rated for symptom progression over the next 5 days. Field trials are conducted at the Texas A&M AgriLife Research and Extension Center in Halfway to evaluate Verticillium wilt tolerance of Dr. Dever's entries as well as some commercial entries submitted through Dr. Dever's germplasm testing program. Two-row plots are planted with four replications per entry. Plots are rated for wilt incidence, defoliation, and yield. The G. hirsutum collection within the USDA at College Station, TX has been partially screened for Verticillium wilt resistance, with only a few lines identified with partial resistance. I screened the rest of the collection that was available through Dr. Dever's program to this disease and found similar results to previous screening work. We will be crossing the most resistant entries with Fibermax (FM) 989 and with CA 4002 (a partially resistant breeding line from Dr. Dever's program). Dr. Dever will then select plants that exhibit day neutral flowering and begin to incorporate the crosses into her breeding program. Ultimately the material will be screened for enhanced Verticillium wilt resistance. A field testing program will be maintained to test commercial entries for their responses to Verticillium wilt. At each site, at least 32 entries are placed in two row plots with four replications in a randomized complete block design. Entries are evaluated for stand, wilt incidence, defoliation, and yield.Root-knot nematodes- Germplasm from the cotton breeder (Jane Dever) and from various commercial seed companies is screened for resistance to this organism. Autoclaved sandy soil is added to cups and inoculated with 1,000 to 2,000 eggs of M. incognita (grown on tomato plants). Plants may be evaluated at 35 days after planting for root galls; and at 60 days after planting for root-knot nematode reproduction. Field plots are used at the AGCARES facility (Lamesa, TX) to evaluate germplasm in conjunction with Dr. Jane Dever. Plots are sampled late in the growing season for root-knot nematode eggs and J2 (second-stage juveniles). Advanced breeding lines with transgenic traits and commercial cultivars will be evaluated in producer cotton fields for yield and root-knot nematode resistance.Bacterial blight (Xcm): Entries for Dr. Dever's program and commercial entries are screened yearly for their reaction to bacterial blight. Entries are planted into 1 or 2 row plots with typically four replications. Entries are sprayed at least once with a mixture of Xcm isolates that behave typical to race 18. The bacteria are sprayed at 106/ml water in 19 L water/acre where Silwet L-77 is added at 0.2% v/v. Disease symptoms typically occur 14 days later and are rated between 14 and 21 days after application. Disease incidence is used to determine the susceptibility or resistance of the entries. Isolates of Xcm from fields will be collected and tested on four varieties to test for a possible race shift in a growth chamber. A split-plot design is used with four varieties Deltapine (DP) 1454NRB2RF (highly susceptible), FM 1320GL (partially susceptible), FM 1830GLT (resistant), and FM 2484B2F (resistant) as the subplot and Xcm isolate as the main plot, in a RCBD with four replications. Cotton is inoculated by scraping the underside of the cotyledon with inoculum (3-4 days old) growing on carrot PDA media. The seedlings are placed in 100% humidity in a humidity chamber for 1 day, and then transferred to a growth chamber. They are rated for water soaking and other disease symptoms 13 days later. Any isolates that show abnormal reaction are retested. A Pseudomonas syringae has been found at several of the field sites where bacterial blight is able to cause light symptoms on resistant plants during the 2015 and 2016 growing seasons. This bacterial will be investigated as to whether it inteacts with Xcm by co-inoculating the two bacteria in growth chamber experiments. The timing of the inoculations (delayed for P. syringae) and whether it interacts better on some Xcm isolates than other will be investigated similar to what is described above. I will be looking for this organism in all field samples that come in with bacterial blight symptoms to determine if it is present commonly in fields, or just those that are showing bacterial blight in what should be varieties.The effect of crop rotation and irrigation on disease management: The crop rotation and irrigation studies are conducted at the AGCARES (Lamesa, TX) and Helms (Halfway, TX) research farms. AGCARES is a 120-acre circle that maintains three irrigation rates (Base and 30% above and below Base, replicated three times) and a crop rotation with continuous cotton and cotton rotated with wheat. The soil is naturally infested with root-knot nematode. The large plots, which run the length of the wedge are sampled during the growing season for root galls around 45 days after planting, and then soil samples are taken in August or September and assayed for root-knot nematode J2 and eggs. The Helms research farm includes a center pivot irrigation system with three irrigation rates (Base, Base+50% and Base-50%) and two tillage treatments (conventional with bed, and minimum using flat ground), and three replications of each irrigation rate/tillage treatment in a randomized complete block design. Cropping systems maintained currently on this circle are continuous cotton (with or without a cover crop), sorghum/cotton, and wheat/cotton rotations. This field is naturally infested with V. dahliae. The disease data collected includes soil microsclerotia density of the fungus and wilt incidence during the growing season. Fungal microsclerotia densities are obtained from soil samples taken during the winter on whole plots; wilt incidence is measured on three, 35-foot long areas of each plot.Efficacy of biological or chemical treatments on cotton: Small plot, replicated research is conducted with biological or chemical products on cotton. Root-knot nematode related products are tested at the AGCARES facility. Products are applied as seed treatments, liquid or granular infurrows at planting, or sprayed over the top of cotton plants, depending on the protocols. Similar protocols can be conducted for the reniform nematode at the Texas A&M Research Station in Lubbock. Seedling disease trials are typically conducted at the Texas A&M Research station at Lubbock, and plots are inoculated with the pathogen of interest (Rhizoctonia solani or Pythium ultimum) at planting. The pathogens are isolated from local diseased plants and maintained in culture for trials. Measurements include stand, gall counts, nematode counts and yield. Small plot research is also conducted on peanut pod rot on producer fields naturally infested with the disease (typically caused by Pythium myriotylum and R. solani). Plots are planted with one variety and sprayed over-the-top with products of interest at appropriate times of the season. Plots are sampled usually once during the season to evaluate pod rot, after plots are dug (before thrashing), and then harvested with a two-row thrasher. Kernels are rated for grade, damaged kernels, etc. to evaluate effects of disease on peanuts.

Progress 04/03/17 to 02/01/22

Outputs
Target Audience:The primary target audience are the cotton producers of the southern High Plains of Texas. Additional target audiences include producers around the state of Texas, scientists within agribusinesses, USDA-ARS scientists, IPM and county agents within Texas A&M, and plant pathologists, particularly working with cotton. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?A peer reviewed publication on the bacterial blight results is waiting for publication in Plant Health Management. The results from the commercial variety trials for root-knot and reniform nematodes, Verticillium wilt, and bacterial blight have been made available to producers, agribusiness people, county agents, IPM agents, and other interested people in cotton production through the Texas A&M AgriLife Research website, https://lubbock.tamu.edu. A limited number of handouts were also disseminated in producer meetings in 2021. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Resistance sources for bacterial blight in cotton cultivars held up strongly against a collection of bacterial isolates from 2015 to 2020. Some commercial varieties have a mixture of resistant and susceptible plant types within the variety. Some bacterial isolates were more aggressive than others, resulting in a higher proportion of plants with symptoms, within the susceptible, partially susceptible, or partially resistant varieties. However, the pure source of resistance to the B12 gene, S295 allowed no visual symptoms from any bacterial isolates tested. Verticillim wilt was substantial in one of our test fields this year. While it is clear that there have been no varieties developed in recent years with more resistance to FM 2334GLT, there are some dicamba tolerant varieties that have improved resistance to Verticillium wilt compared to several years ago. There were fournew commercial cotton varieties in 2021 with resistance to the reniform nematode. These four varieties all demonstrated good resistance to both root-knot and reniform nematodes. Yield responses in root-knot nematode fields were not quite as good compared to other varieties with only root-knot nematode resistance, but yield responses in reniform nematode fields were excellent compared to all susceptible commercial varieties tested. The 2021 growing season did not favor midmaturing cotton varieties in the reniform nematode test (planted late), so it is possible that these varieties will all perform better given a growing season with more heat units. There was good rain during May, June, and July in the region, and this resulted in better than normal results from some chemical nematicide products that were evaluated. Velum (fluopyram, Bayer CropScience), an at-plant infurrow product had probably it's best season in terms of improving cotton yields in many years. This reinforces how difficult it is to get chemicals to distribute properly in the soil, in a relatively dry climate, and the consistency of resistance cultivars compared to chemicals for managing nematodes in this region. Biological products that were tested for nematode control in 2021 did not perform very well against the reniform nematode, inspite of the unusually high rainfall.

Publications

  • Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Zhang, J., Y. Zhu, A. Abdelraheem, H. D. Elkins-Arce, J. Dever, T. Wheeler, T. Isakeit, K. Hake, and T. Wedegaertner. 2021. Use of a latin square design to assess experimental errors in field evaluation of cotton for resistance to Fusarium wilt race 4. Crop Science https://doi.org/10.1002/csc2.20673.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Elassbli, H., Y. Zhu, Z. Abdelraheem, T. Wheeler, T. Wedegaertner, and J. Zhang. 2021. Genetic analysis of resistance to bacterial blight Race 18 and B12-linked marker analysis in U.S. upland cotton. Crop Science 61(5):3458-3468. https://doi.org/10.1002/csc2.20567
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Wheeler, T. A., T. Harris, R. Bart, J. Woodward, T. Isakeit, T. Allen, and R. C. Kemerait. 2021. Response of Xanthomonas citri pv. malvacearum isolates to cotton differing in susceptibility to the bacterium and their predicted type III effectors. Plant Health Progress https://doi.org/10.1094/PHP-06-21-0090-RS.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Zhu, Y., A. Abdelraheem, P. Cooke, T. Wheeler, J. Dever, T. Wedegaertner, K. Hake, and J. Zhang. 2021. Comparative analysis of infection process in Pima cotton differing in resistance to Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum race 4. Phytopathology 10.1094/PHYTO-05-21-0203-R.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Elassbli H., Abdelraheem A., Zhu Y., Teng Z., Wheeler T.A., Kuraparthy V., Hinze L., Stelly D.M., Wedegaertner T., Zhang J. 2021. Evaluation and genome-wide association study of resistance to bacterial blight race 18 in U.S. Upland cotton germplasm. Mol Genet Genomics. May;296(3):719-729. doi: 10.1007/s00438-021-01779-w. Epub 2021 Mar 29. PMID: 33779828.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Abdelraheem, A., Y. Zhu, J. K. Dever, T. A. Wheeler, T. Wedegaertner, K. Hake, and J. Zhang. 2021. Identification of resistance sources to Fusarium wilt race 4 in Gossypium barbadense and cultivated Asiatic diploid species. Euphytica 217, article 153.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Abdelraheem, A., Y. Zhu, J. Dever, T. Wheeler, T. Wedegaertner, K. Hake, and J. Zhang. 2021. Diallel analysis of resistance to Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) race 4 in American pima cotton. Crop Sci. 61 (6): 4000-4011. https://doi.org/10.1002/csc2/20606.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Zhang, J., Abdelraheem, A., Zhu, Y., Wheeler, T. A., Dever, J. K., Yu, J., Shi, Y., Yuan, Y., and Wedegaertner, T. 2021. Dynamic responses to Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) race 4 in two introgressed populations of Upland cotton (Gossypium hirsutum). Euphytica 217, 98. https://doi.org/10.1007/s10681-021-02836-6
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Zhang, J., Abdelraheem, A., Zhu, Y., Wheeler, T. A., Dever, J. K., Nichols, R., and Wedegaertner, T. 2021. Importance of temperature in evaluating cotton for resistance to Fusarium wilt caused by Fusarium oxysporum f. sp. vasinfectum race 4. Crop Science 61:1783-1796. https://doi.org/10.1002/csc2.20446.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Zhu, Y., Abdelraheem, A., Wheeler, T. A., Dever, J. K., Wedegaertner, T., Hake, K. D., and Zhang, J. 2021. Interactions between cotton genotypes and Fusarium wilt race 4 isolates from Texas and resistance evaluation in cotton. Crop Science 61:1809-1825. https://doi.org/10.1002/csc2.20469.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Denwar, N. N., Simpson, C. E., Starr, J. L., Wheeler, T. A., and Burow, M. D. 2021. Evaluation and selection of interspecific lines of groundnut (Arachis hypogaea L.) for resistance to leaf spot disease and for yield improvement. Plants 10,873. https://doi.org/10.3390/plants10050873.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Elassbli, H., A. Abdelraheem, Y. Zhu, Z. Teng, S. Sanogo, T. A. Wheeler, T. Wedegaertner, and J. Zhang. 2021. Evaluation and analysis of commercial cultivars and elite breeding lines for resistance to the bacterial blight pathogen race 18 in cotton. Euphytica 21, article 21.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Babilonia, K., Wang, P., Liu, Z., Jamieson, P., Mormile, B., Rodrigues, O., Zhang, L., Lin, W., Danmaigona Clement, C., Menezes de Moura, S., Alves?Ferreira, M., Finlayson, S. A., Nichols, R. L., Wheeler, T. A., Dever, J. K., Shan, L., He, P. 2021. A nonproteinaceous Fusarium cell wall extract triggers receptor?like protein?dependent immune responses in Arabidopsis and cotton. New Phytologist 230:275-289. https://doi.org/10.1111/nph.17146
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Wheeler, T. A. and J. Dever. 2021. Variety response to Verticillium wilt and bacterial blight in the Southern High Plains of Texas. pp 83-93. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Abdelraheem, A., Y. Zhu, T. Wheeler, J. Dever, J. Ma, J. Yu, Y. Shi, Y. Yuan, and T. Wedegaertner. 2021. Genetic mapping for resistance to Fusarium wilt in two introgressed populations of upland cotton. P. 112. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Zhu, Y., J. Zhang, J. Dever, T. Wheeler, and T. Wedegaertner. 2021. Identification of resistance sources to Fusarium wilt race 4 in Gossypium barbadense and cultivated diploid cotton species. P. 113. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Monclova-Santana, C. and T. A. Wheeler. 2021. FOV4 and Fusaria causing symptoms in cotton. P. 115. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Zhu, Y., P. Cooke, J. Zhang, T. Wheeler, J. K. Dever, and T. Wedegaertner. 2021. Comparative analysis of infection process in cotton differing in resistance to Fusarium wilt caused by Fusarium oxysporum f.sp. vasinfectum race 4. P. 132. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Ulloa, M., R. B. Hutmacher, T. Frigulti, P. A. Roberts, M. L. Ellis, J. K. Dever, T. A. Wheeler, J. Zhang, S. Sanogo, S. Hague, P. Payton, and R. L. Nichols. 2021. Resistance/tolerance to Fusarium wilt race 4 (FOV4) in upland (Gossypium hirsutum L.) cotton for germplasm public release. P. 160. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Braden, C., D. McCallister, K. Lange, Wayne Keeling, Will Keeling, K. Lewis, and T. Wheeler. 2021. Cropping system effects on cotton variety performance in the presence of root-knot nematodes in the Southern High Plains of Texas. P. 214-221. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Faske, T. R., T. W. Allen, Z. Grabau, R. C. Kemerait, D. Langston, K. S. Lawrence, J. Mueller, P. Price, L. D. Thiessen, and T. Wheeler. 2021. Beltwide nematode research and education committee report: Field performance of seed- and soil-applied nematicides, 2020. Pp. 326-329. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Dotray, J., T. A. Wheeler, C. Monclova-Santana, J. Chagoya, and J. Shockey. 2021. Screening commercial cotton varieties for Fusarium wilt and root-knot nematode resistance. P. 389. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: McCullock, M., J. Dudak, T. Isakeit, B. McKnight, T. Wheeler, C. Monclova-Santana, G. Morgan, and R. Noland. 2021. Evaluating genetic resistance and nematicides for reniform nematode management in cotton. P. 597-599. 2021 Beltwide Cotton Conferences, Virtual, January 5-7, 2021.


Progress 10/01/20 to 09/30/21

Outputs
Target Audience: Nothing Reported Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Please see the final report for this project.

Publications


    Progress 10/01/19 to 09/30/20

    Outputs
    Target Audience:The target audiences affected by my work during this reporting period include plant pathologists, cotton breeders, Texas A&M scientists, IPM agents, county agents, cotton producers, crop consultants, USDA scientists, and people working in agindustries (in the areas of seed and chemicals). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?The results from variety trials were disseminated during winter meetings to producers, crop consultants, IPM agents, county agents, other plant pathologists, and other agricultural scientists. In addtion, these results were sent to all the cotton seed companies that participated in the trials and also placed on the Texas A&M AgriLife Research and Extension Center in Lubbock web site (https://lubbock.tamu.edu). Meetings where information was disseminated by T. Wheeler included the Beltwide Cotton Conferences, and meetings in Lubbock, TX, Lamesa, TX, Muncie, TX, Plainview, TX, and Seminole, TX. In addition, slides were prepared and paper copies of resultsand sent to extension specialists in Texas presenting at county meetings, for additional dissemination. Greenhouse trial results were sent to the cotton breeders/industry representativeswhose germplasm was tested. Results from chemical/biological field trials for experimental materials was sent to the agindustry contact person. What do you plan to do during the next reporting period to accomplish the goals?Similar types of trials are expected to be conducted during the next year. They include greenhouse trials for resistance to Verticillium dahliae, Fusarium oxysporum f.sp. vasinfectum, Meloidogyne incognita, and Rotylenchulus reniformis. Field trials to screen germplasm will be conducted in producer fields and at the Texas A&M AgriLife Research test sites. Trials to test chemical or biological products will also be tested in producer fields and the Texas A&M AgriLife Research test sites. Large plot trials to examine the impact of cultural activities on Verticillium wilt will be conducted at the Halfway, TX Texas A&M AgriLife Research site, and for root-knot nematode, will be conducted at the AGCARES test site near Lamesa. A Fusarium wilt nursery for race 4 to test germplasm response to this pathogen is expected to occur near Fabens, TX.

    Impacts
    What was accomplished under these goals? Commercial cotton varieties and breeding lines and Texas A&M AgriLife Research breeding lines were successfully tested for responses to bacterial blight, Fusarium wilt, Verticillium wilt, root-knot nematode, and reniform nematode. Information was communicated to producers, seed company representatives, IPM agents, crop consultants, and Texas A&M cotton breeders. In terms of the effects of cultural practices on plant pathogens, tests were successfully completed in 2019/2020 and results communicated to cooperators, producers, IPM agents, county, agents, and crop consultants. In addition, a peer-reviewed publication was obtained on effects of tillage systems and irrigation on cotton yields and Verticillium dahliae symptom expression and microsclerotia density. Chemical field trials were successfully completed and confidential information was communicated to agindustry cooperators. In addition, the responses to commercial products were communicated during winter meetings to producers, IPM agents, crop consultants, and fellow plant pathologists and scientists from various entities.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Wheeler, T.A., Siders, K., Monclova-Santana, C., and Dever, J.K. 2020. The relationship between commercial cotton cultivars with varying Meloidogyne incognita resistance genes and yield. Journal of Nematology 52:e2020-64. DOI: 10.21307/jofnem-2020-064.
    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Wheeler, T.A., Borkovsky, J.P., Keeling, J.W., Keeling, W., and McCallister, D. 2020. The effects of tillage system and irrigation on Verticillium wilt and cotton yield. Crop Protection 137:105305. https://doi.org/10/1016/j.cropro.2020.105305.
    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Ayele, A.G., Wheeler, T.A., and Dever, J.K. 2020. Impacts of Verticillium wilt on photosynthesis rate, lint production, and fiber quality of greenhouse-grown cotton (Gossypium hirsutum). Plants 2020, 9, 857. Doi: 10.3390/plants9070857.
    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhang, J.A., Abdelraheem, A., Zhu, Y., Wheeler, T.A., Dever, J.K., Elkins-Arce, H., Nichols, R., and Wedegaertner, T. 2020. Pedigree selection under field conditions with Acala 1517-08 and its glandless derivatives for development of cotton resistant to Fusarium wilt caused by Fusarium oxysporum f.sp. vasinfectum race 4. Euphytica 216:155, https://doi.org/10/1007/s10681-020-02691-x.
    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhang, J.F., Abdelraheem, A., Zhu, Y., Wheeler, T.A., Dever, J.K., Frelichowski, J., Love, J., Ulloa, M., Henkins, J.N., McCarty, J.K. Jr., Nichols, R., and Wedegaertner, T. 2020. Assessing genetic variation for Fusarium wilt race 4 resistance in tetraploid cotton by screening over three thousand germplasm lines under greenhouse or controlled conditions. Euphytica 216:108 (2020) https://doi.org/10.1007/s10681-020-02646-2.
    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhang, J.F., Bourland, F.M., Wheeler, T.A., and Wallace, T.P. 2020. Bacterial blight resistance in cotton: Genetic basis and molecular mapping. Euphytica 216(7):111. https://doi.org/10/1007/s10681-020-02630-w.
    • Type: Journal Articles Status: Published Year Published: 2020 Citation: Zhou, W., Verma, V.C., Wheeler, T.A., Woodward, J.E., Starr, J.L., and Sword, G.A. 2020. Tapping into the cotton fungal phytobiome for novel nematode biological control tools. Phytobiomes Journal 4(1): 19-26. https://doi.org/10/1094/PBIOMES-08-19-0043-SC.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Pate, S., Kelly, H.M., Guyer, R., Allen, T.W., Wilkerson, T.H., Colyer, P.D., Lawrence, K.S., Isakeit, T., Kemerait, R.C., Mehl, H.L., Price, P., Rojas, A., Thiessen, L., and Wheeler, T. 2020. An assessment of seed treatment efficacy and cotton seedling disease presence using innovative techniques. Pp. 327-328. Beltwide Cotton Conferences, Austin, TX January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Kelly, H.M., Guyer, R., Pate, S., Allen, T.W., Wilkerson, T., Colyer, P.D., Isakeit, T., Kemerait, R.C., Lawrence, K.S., Mehl, H.L., Price, P., Rojas, A., Thiessen, L., and Wheeler, T. 2020. Report of the cottonseed treatment committee for 2019. Pp. 393-402. Beltwide Cotton Conferences, Austin, TX January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Dudak, J., Isakeit, T., Noland, R., Wheeler, T., and Morgan, G. 2020. Impact of cotton genetics and nematicides on reniform nematode populations. Pp. 496-499. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Wheeler, T. A. 2020. Report of the bacterial blight committee for the 2019 year. Pp. 259-260. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Fraske, T.R., Allen, T.W., Grabau, Z., Hu, J., Kemerait, R.C., Lawrence, K.S., Mehl, H.L., Mueller, J., Price, P., Thiessen, L.D., and Wheeler, T. 2020. Beltwide nematode research and education committee report on field performance of seed and soil-applied nematicides, 2019. Pp. 192-196. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Ayele, A.G., Wheeler, T.A., and Dever, J.K. 2020. Effects of Verticillium wilt on photosynthesis, yield, and fiber quality of greenhouse-grown upland cotton lines. P. 121. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Monclova-Santana, C., and Wheeler, T.A. 2020. Screening cotton varieties for reaction to Fusarium wilt (race 1) in the southern high plains. P. 120. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Ballesteros, R., and Wheeler, T.A. 2020. Management of Fusarium wilt and root-knot nematode with Velum Total and Propulse. P. 107-110. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Zhang, J., Abdelraheem, A., Zhu, Y., Wheeler, T., Nichols, R., and Wedegaertner, T. 2020. Greenhouse screening of cotton for Fusarium wilt race 4 resistance in New Mexico. Pp. 85-90. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Wheeler, T.A., and Dever, J. 2020. Effects of Verticillium wilt and bacterial blight on commercial varieties. Pp. 73-79. Beltwide Cotton Conferences, Austin, TX, January 8-10, 2020.


    Progress 10/01/18 to 09/30/19

    Outputs
    Target Audience:The target audiences affected by my work during this reporting period include plant pathologists, cotton breeders, Texas A&M scientists, IPM agents, and county agents, cotton producers primarily in Texas, crop consultants, USDA scientists, and agindustry people. Changes/Problems:Fusarium oxysporum f.sp. vasinfectum was added to the list of diseases to work with in 2018. Management of the race that is common in the Southern High Plains was being handled by the extension specialist Jason Woodward. He left his position in August 2018, so I picked up testing of commercial varieties in this region in 2019. The new extension specialist that replaced Dr. Woodward will need some assistance for a few years to be able to conduct field trials in producer fields, so I will continue to work with Fusarium wilt until she is self sufficient. In addition, the discovery of Fusarium wilt race 4 in the El Paso region in 2017, means that I need to go to that area to screen germplasm for resistance to this race. In 2018 and 2019 a field nursery was established in a 10-acre field near El Paso. In 2020, I hope to also do some greenhouse screening in El Paso with germplasm of interest. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Results were disseminated to cotton scientists and producers through the Beltwide Cotton Conferences in 2019; through the Texas A&M website at Lubbock (lubbock.tamu.edu) and through numerous field days conducted in the Southern and Northern High Plains of Texas. Results from crop rotation studies and Verticillium wilt resulted in a peer-review publication in the journal Crop Protection, which has international readership. What do you plan to do during the next reporting period to accomplish the goals?Similar type studies will be conducted as in the previous year. That includes small plot research trials with varieties and breeding lines in commercial cotton fields that are naturally infested with Verticillium dahliae, Meloidogyne incognita, and Fusarium oxysporum f.sp. vasinfectum race 1. In addition, small plot research involving chemicals, biologicals, and germplasm will be tested on Texas A&M land in Lubbock, Lamesa, and Halfway. I will participate in a cotton breeding nursery infested with Fusarium wilt race 4 in the El Paso region. I will also participate in large plot trials involving cultural methods that can affect root-knot nematodes and Verticillium wilt. Greenhouse work is ongoing to test isolates of Xanthomonas citri pv. malvacearum (causing bacterial blight) against lines that should be susceptible and resistant to race 18. If symptoms are expressed on the resistant line (S295), that would signify a shift in race for this region. Greenhouse work is also utilized to screen cotton breeding lines for resistance to Verticillium dahliae, Meloidogyne incognita, and Rotylenchulus reniformis. Some greenhouse screening of germplasm against Fusarium oxysporum f.sp. vasinfectum will also occur.

    Impacts
    What was accomplished under these goals? Bacterial blight resistance in new cotton varieties was confirmed or identified from field trials in varieties/breeding lines from Deltapine, Fibermax/Stoneville, NexGen, Croplan Genetics, Dynagro, and Phytogen. Verticillium wilt tolerance (yield response) was measured in small plot field trials with approximately 75 commercial entries during the fall of 2018. Direct measurements of wilt and defoliation during the summer of 2019 were made, however, disease was very light in 2019 and only the most susceptible cultivars could be identified. Most new cultivars in 2019 will need to be rescreened in the next year. Root-knot nematode tolerance (yield) and reproduction were measured in varieties from Phytogen, Deltapine, and BASF. Reniform nematode tolerant breeding lines were tested in 2019 and those from Phytogen were both resistant (lower nematode buildup) and had at least double the yields of manycommercial varieties in a reniform nematode field. Progress was made as well with screening trials for the Texas A&M breeder in Lubbock for resistance to bacterial blight, Verticillium wilt, root-knot nematodes, and reniform nematodes. Studies involving cultural control of Verticillium wilt were conducted using crop rotation, irrigation rate, and tillage systems. A paper was published demonstrating that crop rotation was initially successful at managing Verticillium wilt, but over time, became ineffectual. Higher irrigation rates continue to have the most Verticillium wilt. An economic analysis from 2014-2018 demonstrated that the most profitable system was continuous cotton with a terminated wheat cover, and using a moderate (approximately 8-inches of water/year) irrigation rate had the highest returns over those five years. A crop rotation study in a field infested with root-knot nematode demonstrated that a cotton/wheat/fallow rotation had much higher yields (and lower root-knot nematode densities) than continuous cotton. Interesting, continuous cotton with a wheat cover often had very different yields when compared with continuous cotton and no cover with conventional tillage. However, it depends on the year, which onehas superior yields. There are impacts of the tillage/cover crop practices that may effectroot-knot nematodes or other factors, that are not well understood. Small plot research plots were also used to evaluate chemical and biological products against nematodes and seedling disease. Small plot Fusarium wilt (presumably race 1) trials were conducted in three producer fields in the Southern High Plains in 2019. While no variety appeared to be highly resistant to this disease(i.e. plant death after initial emergence occurred in all varieties), ST 4946GLB2 had among the highest yields in all three fields and appears to have some tolerance to the disease. Greenhouse trials were conducted with a small subset of varieties/breeding lines, and signficant differences can be measured using root-dip technique with the fungus (Fusarium). However, it is more difficult to see these differences in disease symptoms of the same varieties in the field. Fusarium wilt race 4 small plot trials were conducted in the El Paso area in 2018 and 2019. Stand loss and root damage were readily measured in cotton varieties and breeding lines. There does appear to be some resistance differences among entries in field trials. Results of the trials involving commercial entries tested in root-knot nematode and Verticillium wilt fields and inoculations with bacterial blight, were made available to the public (particularly to cotton producers) through the Texas A&M website at Lubbock (lubbock.tamu.edu) and through handouts at field days that were conducted in many of the counties of the Southern and Northern High Plains.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2018 Citation: Zhou, W., Wheeler, T. A., Starr, J. L., Valencia, C. U., and Sword, G. A. 2018. A fungal endophyte defensive symbiosis affects plant-nematode interactions in cotton. Plant and Soil 422:251-266.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Cox, K. L. Jr., Babilonia, K., Wheeler, T., He, P., and Shan, L. 2019. Return of old foes - recurrence of bacterial blight and Fusarium wilt of cotton. Current Opinion in Plant Biology 50:95-103.
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: Phillips, A. Z., Wheeler, T. A., Woodward, J. E., and Bart, R. S. 2018. Pseudomonas syringae pathogen causes foliar disease of upland cotton in Texas. Plant Disease 102:1171.
    • Type: Journal Articles Status: Published Year Published: 2019 Citation: Wheeler, T. A., Bordovsky, J. P., and Keeling, J. W. 2019. The effectiveness of crop rotation on management of Verticillium wilt over time. Crop Protection 121:157-162.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Kong, L., Liu, Z., Jamieson, P., Woodward, J., Hague, S., He, P., Shan, L., Wheeler, T., Dever, J., Ulloa, M., and Coleman, J. 2019. Dissecting the disease mechanism of Fusarium oxysorum f.sp. vasinfectum race 4 (FOV4) in cotton. Beltwide Cotton Conferences, New Orleans, LA, Jan 8-10, 2019. P. 718
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Ayele, A., Wheeler, T. A., and Dever, J. K. 2019. Impact of Verticillium wilt on fiber quality of greenhouse-grown cotton (Gossypium hirsutum L.) breeding lines. Beltwide Cotton Conferences, New Orleans, LA, Jan. 8-10, 2019. P. 103.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Faske, T. R., Allen, T. W., Grabau, Z., Kemerait, R. C., Lawrence, K. S., Mehl, H. L., Overstreet, C., Thiessen, L. D., and Wheeler, T. 2019. Beltwide nematode research and education committee report on field performance of seed-applied and soil-applied nematicides, 2018. Beltwide Cotton Conferences, New Orleans, LA, Jan. 8-10, 2019. Pp. 75-78.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Wheeler, T. A. and Dever, J. K. 2019. Effect of Verticillium wilt and bacterial blight on commercial cotton varieties in 2018. Beltwide Cotton Conferences, New Orleans, LA, Jan. 8-10, 2019. Pp. 65-74.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Elassbli, H., Abdelraheem, A., Sanogo, S., Zhang, J., Kuraparthy, V., Stelly, D. M., Hinze, L., Wheeler, T. A., and Wedegaertner, T. 2019. A genome-wide association study of resistance to Fusarium wilt and bacterial blight in US upland cotton germplasm. Beltwide Cotton Conferences, New Orleans, LA, Jan. 8-10, 2019. Pp. 16-20.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Zhu, Y., Abdelraheem, A., Teng, Z., Sanogo, S., Zhang, J., Wheeler, T., and Wedegaertner, T. 2019. Pathogenicity test of Fusarium wilt and screening germplasm lines for Fusarium wilt resistance in cotton. Beltwide Cotton Conferences, New Orleans, LA, Jan. 8-10, 2019. P 15.


    Progress 10/01/17 to 09/30/18

    Outputs
    Target Audience:The cotton producers of the southern High Plains are the primarly target audience. Results from cotton trials to test the performance of commercial varieties to Verticillium wilt, bacterial blight, and root-knot nematodes were made available at the Texas A&M center at Lubbock website (http://lubbock.tamu.edu) and with handouts at every winter meeting held in the Southern High Plains. Management of these plant pathogens based on cultural, varietal, and chemical practices were also shared with producers, crop consultants, and agindustry professionals at meetings. Bacterial blight has been a high focus point recently, and a presentation was made to cotton breeders (university, USDA-ARS, and commercial) at the Cotton Beltwide meeting in 2018 on breeding for resistance to this pathogen. Changes/Problems:Fusarium wilt of cotton caused by race 4 is a new pathogen in Texas, and is currently limited to the El Paso valley. It is necessary to work with the pathogen in that region, both in field trials that must be done in producer fields, and in greenhouse trials. We have made the decision not to work with it in the Southern High Plains region, even in my laboratory or greenhouse space. This creates some problems by having to spend time away from the southern High Plains during the summer at critical times for other projects, and also in trying to work with the pathogen in the Texas A&M research station at El Paso. There is currently no plant pathologist or trained pathologist assistant associated with the El Paso station. It is also difficult to find and establish sites for germplasm evaluations. Texas A&M AgriLife Research is spending considerable resources on work in the El Paso valley on this pathogen. The progress with breeding for resistance to this new pathogen will hopefully improve over the next few years, but there are a lot of issues to work through at this time. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?The results of the Verticillium wilt, root-knot nematode, and bacterial blight variety trials were written into brief, easy-to-read formats and made available at the Texas A&M center at Lubbock website (http://lubbock.tamu.edu). In addition, the extension specialist, Jason Woodward, disseminated them as handouts at all of the winter county meetings for the northern and southern High Plains. The Verticillium wilt and bacterial blight results were also presented at the Cotton Beltwide meetings in 2018 and published in the proceedings for that meeting. The results from nematicide and seed treatment fungicide trials were made available to the companies that sponsored the tests. Limited test results were also used in presentations to cotton producers and when making recommendations to cotton producers that want to discuss nematode management for their farms. What do you plan to do during the next reporting period to accomplish the goals?1. Collect and test isolate of Xanthomonas citri pv. malvacearum (Xcm) and Pseudomonas syringae from fields in Texas, to determine pathogenicity and whether Xcm behaviour is consistent with race 18. 2. Conduct field inoculations with Xcm for cotton breeders to evaluate their germplasm for resistance to bacterial blight (race 18). 3. Conduct small plot replicated field trials on naturally infested Verticillium wilt fields to evaluate the effect of the disease on commercial and public breeder germplasm. Inoculated trials in the greenhouse will also be used to evaluate plant selections made in 2018. 4. Conduct small plot, replicated field trials on naturally infested root-knot nematode fields to evaluate the effect of the nematode on commercial germplasm. Greenhouse trials will primarily be used to evaluate resistance to root-knot nematode on germplasm from the Texas A&M breeder at Lubbock. 5. Conduct small plot evaluations on germplasm for resistance to the reniform nematode, Rotylenchulus reniformis. 6. Conduct small plot field evaluations on Texas A&M cotton breeders germplasm in a Fusarium wilt (race 4) field in the El Paso valley. In addition, a lab and greenhouse facility at the Texas A&M station in El Paso will be equipped to conduct tests with Fusarium wilt race 4. Trials will be initiated if possible during 2019. 7. Study the effect of cropping systems, irrigation rate, and tillage on Verticillium wilt and defoliation, and V. dahliae microsclerotia density. 8. Study the effect of cropping systems, irrigation rate, and variety on root-knot nematode population density. 9. Study the impact of nematicide treatments on root-knot and reniform nematode symptoms, population density, and yield impact.

    Impacts
    What was accomplished under these goals? In 2018, 125 commercial breeding lines and varieties were evaluated for Verticillium wilt incidence and defoliation in naturally infested, replicated trials at three producer sites or the Texas A&M station at Halfway), and 418 breeding lines were evaluated at the Verticillium wilt nursery for the Texas A&M cotton breeder in Lubbock. In addition, a greenhouse replicated trial was conducted evaluating the best lines from the 2017 season for Verticillium wilt resistance in inoculated pots and taken to yield. It appears that the Texas A&M breeding material can equal or surpass yield compared with the best commercial variety, under the inoculated greenhouse conditions. This represents significant progress with the breeding program. Evaluation of resistance to bacterial blight of cotton was accomplished by inoculating the cotton breeder's nurseries at the Texas A&M research center at Lubbock (592 plots) and rating them for blight resistance. Commercial seed company nurseries were also inoculated with the bacteria, which allows for the company cotton breeders to evaluate early generation material and select for blight resistant progeny when possible. I have emphasized using bacterial blight resistant varieties with the cotton seed companies and encouraged cotton producers to plant these resistant varieties. In 2018, blight resistant varieties were planted on 67% of the cotton acres in Texas, which is a good improvement from 2016 when blight resistant varieties were only planted on 34% of Texas cotton acres. Resistance to root-knot nematode (Meloidogyne incognita) in cotton was evaluated in replicated field trials (three locations with 32 to 36 entries/location), and for a trial with commercial entries that is conducted by the Texas A&M cotton breeder in Lamesa. Breeding lines for the Texas A&M cotton breeder were screened in the greenhouse during the winter for root-knot nematode resistance (183 entries in replicated trials). Six of the entries appeared to have 2-gene resistance to root-knot nematode, based on egg production after 60 days. Nine lines were evaluated in a replicated field trial with root-knot nematode. A Fusarium wilt (race 4) nursery was established in the El Paso valley, and approximately 1800 plots containing Texas A&M breeder germplasm (571 lines) were evaluated for resistance to FOV4 based on plant stand, seedling death, and root symptoms. Large plot crop rotation and irrigation rate studies were conducted at a root-knot nematode site and a Verticillium wilt site. The effects of a wheat/fallow/cotton rotation was compared with continuous cotton on root-knot nematode population buildup. This rotation was begun in 2014, and from 2014 to 2016, there was a significant reduction in root-knot nematode density in the wheat/fallow/cotton rotation compared with continuous cotton. Part of the study involved 5 cotton varieties, and 4 of the 5 varieties had 1 or 2-gene resistance to root-knot nematode. The overall buildup of root-knot nematode even in the continuous cotton was slow, because of the nematode resistant varieties in the cropping systems trials. In 2017 and 2018, varieties were changed and 4 of the 5 varieties were susceptible to root-knot nematode. There was a dramatic increase in root-knot nematode density in the continuous cotton, but with the wheat/fallow/cotton rotation, the nematode density continued to stay below damaging levels. In the Verticillium wilt project, there has historically been more buildup of Verticillium dahliae in continuous cotton than a cotton/cotton/sorghum rotation. However, eventually the fungus increased to damaging levels in rotated cotton ground. A new cropping systems and a tillage comparison was added in 2014. At this time, the cotton/sorghum rotation and the cotton/wheat/fallow rotations have as much or more V. dahliae in the soil as continuous cotton. The soil temperature is cooler and soil moisture is higher in these crop rotation systems, and that may have led to more disease and damage. In addition, the reduced tillage/flat ground system has increased disease severity than the conventional tillage/bed system, in those rotated cotton systems and under the highest irrigation rate (where the disease is always the most severe). Again, the reduced tillage system and highest irrigation rates lead to the coolest soil temperature and highest soil moisture. Chemical or biological nematicide trials were conducted with Bayer CropSciences, BASF, Syngenta, Monsanto (now Bayer), Albaugh, and Adama products. These tests were conducted at root-knot nematode and reniform nematode sites. No products appeared to significantly decrease root-knot nematode early season gall formation on cotton, or either nematode species reproduction later in the season. Soil moisture was particularly limited this year, due to an extremely dry winter and spring, and then very high temperatures and wind in the latter part of May. These factors tend to reduce the distribution of the nematicides in the soil/root interface.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2018 Citation: Crutcher, F. K., M. A. Henry-Gregory, H. H. Wilkinson, S. E. Duke, T. Wheeler, and C. M. Kenerley. 2017. Characterization of Sclerotinia minor populations in Texas peanut fields. Plant Pathology 67:839-847.
    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Phillips, A. Z., Berry, J. C., Wilson, M. C., Vijayaraghavan A., Burke J., Imani Bunn, J., Allen, T. W., Wheeler, T., and Bart, R. S. 2017. Genomics-enabled analysis of the emergent disease cotton bacterial blight. PLOS Genetics 13(9): e1007003. https://doi.org/10.1371/journal.pgen.1007003
    • Type: Book Chapters Status: Awaiting Publication Year Published: 2018 Citation: Wheeler, T. A., J. E. Woodward, N. Walker. 2018. Plant parasitic nematodes of Texas and Oklahoma. Eds (John Chitambar and Sergei Subbotin), in: Plant Parasitic Nematodes in Sustainable Agriculture in North America. Springer International Publishing.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Woodward, J. E., T. A. Wheeler, and T. Isakeit. 2018. Overview of cotton diseases in west Texas in 2017. P. 164. Beltwide Cotton Conferences, San Antonio, TX Jan 3-5, 2018.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Wheeler, T. A., J. K. Dever, and J. E. Woodward. 2018. The response of varieties to Verticillium wilt and bacterial blight in the Southern High Plains of Texas. Pp. 587-594. 2018 Beltwide Cotton Conferences, San Antonio, TX, Jan. 3-5 2018.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Wheeler, T. A. 2018. Bacterial blight on cotton. Pp. 11-18. 2018 Beltwide Cotton Conferences, San Antonio, TX Jan 3-5, 2018.
    • Type: Journal Articles Status: Published Year Published: 2018 Citation: Phillips, A. Z., T. A. Wheeler, J. E. Woodward, and R. S. Bart. 2018. Pseudomonas syringae pathogen causes foliar disease of upland cotton in Texas. Plant Disease 102:1171.


    Progress 04/03/17 to 09/30/17

    Outputs
    Target Audience:The target audience includes scientists that read the journal articles, crop consultants, producers, extension specialists, USDA-ARS scientists, plant pathologists and associated people who attend the Beltwide Cotton Conference and American Phytopathologists Association annual meeting, and agribusiness people involved with cotton and peanuts. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?The results have been presented at field days, and presentations to scientists, producers, consultants, and agriculture industry representatives. A symposium on bacterial blight of cotton occurred at the annual meeting for the American Phytopathological Society in 2017. I made a presentation in this symposium. A presentation was also made at the Beltwide Cotton Conference in 2017 and field results from Verticillium wilt, root-knot nematode, and bacterial blight were made. There are a number of reports that are present at the research station website (lubbock.tamu.edu) that include results from the field trials that were completed in 2016 and it will be updated as soon as harvest results are completed from 2017. What do you plan to do during the next reporting period to accomplish the goals?1. Collect and test isolates of Xcm and P. syringae from fields in Texas, to determine pathogenicity and whether Xcm is consistent with race 18. 2. Conduct field inoculations with Xcm for cotton breeders to rate their germplasm and varieties. 3. Conduct field trials on naturally infested fields with V. dahliae and root-knot nematode to determine the responses of commercial varieties, advanced breeding lines, and public breeder's germplasm. 4. Study the effect of cropping system, irrigation rate, and tillage system on Verticillium wilt and V. dahliae density; and cropping system and irrigation rate of root-knot nematode galling and population density. 5. Study the impact of nematicide treatments on root-knot and reniform nematodes and subsequent yields. 6. Study the impact of crop rotation with hosts and nonhosts and fallow on reniform nematode density and impact to cotton.

    Impacts
    What was accomplished under these goals? Commercial cotton varieties and advanced commercial breeding lines were successfully rated for their resistance to bacterial blight, caused by Xanthomonas citri pv. malvacearum (Xcm) at the Texas A&M Research and Extension Center in Lubbock. Germplasm for both public and private cotton breeders was successfully inoculated with this bacteria and we also rated the public breeder's material for resistance to this disease. Commercial nurseries that were successfully inoculated with Xcm included All-Tex/Dynagro Cotton, Americot (2 locations), Bayer CropSciences, Monsanto, and Phytogen (2-locations, DowAgrosciences/Dupont). There is a higher emphasis being placed on blight resistant varieties in Texas in 2017 than had been found in the last few years (% of blight susceptible varieties planted in 2015, 2016, and 2017 were 59, 66, and 49%). Isolates of Xcm were collected from symptomatic fields, and 91 isolates were tested (some of these were collected in 2016) and confirmed as consistent with race 18. A previously unknown pathogen of cotton, Pseudomonas syringae, was also found present in some sites where Xcm occurred. We have not yet been able to prove that the P. syringae is responsible for the occassional breakdown in resistance to Xcm that has occurred at some sites in Texas. P. syringae was identified in 8 fields with bacterial blight in Texs in 2017 (5 different counties). These isolates were tesed for pathogenicity on cotton (two varieties) and 20 were able to cause disease symptoms. Resistance ratings for Verticillium wilt were also successfully accomplished for variety/germplasm at three Verticillium wilt sites and for root-knot nematodes at three locations in 2017. Inoculated greenhouse experiments with V. dahliae and root-knot nematode for both public and commercial breeders were successfully completed. Two trials to test reproduction of reniform nematode on commercial cotton varieties in the greenhouse were successfully completed. Measurements on the impact of crop rotation, irrigation, and tillage system were successfully accomplished for Verticillium wilt. High irrigation rate is still the most important factor influencing diseaes severity, but is critical for high cotton yields. Microsclerotia density is still mainly impacted by a continuous cotton system that was in place from 2001 to 2013 versus a cotton/cotton/sorghum rotation that was in place during those same years. More recent rotations (wheat/fallow/cotton and sorghum/cotton) have had less impact. This may be due to the overall irrigation amounts in more recent years (since 2010 where the medium rate has been based on an evapotranspriation rate of 60%) versus an earlier medium rate where ET = 80% (2001 to 2009). Tillage treatment which appeared to have a substantial impact on disease and subsequently on yield in 2016 (minimum tillage/flat ground had less disease and higher yields), has also shown the same trend for both wilt incidence and defoliation in 2017 (less disease in the minimum tillage system compared with conventional tillage). Measurement of the impact of crop rotation and irrigation on root-knot nematode gall formation on roots and population densities was accomplished in 2017. The wheat/fallow/cotton system had fewer galls and lower root-knot nematode density than did the continuous cotton system (with and without a wheat cover). Irrigation rate had only minimal impact on root galls and root-knot nematode densities in 2017. Chemical and biological nematicide treatments were tested for various companies in small plot root-knot and reniform nematode cotton trials. These came in the form of seed treatments, liquid infurrow treatments at planting, and a liquid side-dress treatment after emergence. Seed treatment fungicides were also tested on cotton seed inoculated with Rhizoctonia solani. Disease conditions for both nematode species and seedling disease were adequate in 2017 to achieve an understanding of product efficacy in this environment. A peanut pod rot study was conducted to test the effect of regular nozzles versus dropped nozzles with a high water volume, on several different fungicides for Pythium pod rot control. Results were disappointing, with no significant impact on the amounts of pod rot found.

    Publications

    • Type: Journal Articles Status: Published Year Published: 2017 Citation: Cox, K. L. Jr., F. Meng, K. E. Wilkins, F. Li, P. Wang, N. J. Booher, S. C. D. Carpenter, L-Q. Chen, H. Zheng, X. Gao, Y. Zheng, Z. Fei, J. Z. Yu, T. Isakeit, T. Wheeler, W. B. Frommer, P. He, A. J. Bogdanove, and L. Shan. 2017 TAL effector driven induction of a SWEET gene confers susceptibility to bacterial blight of cotton. Nature Communications 8, Article number: 15588 (2017) doi:10.1038/ncomms15588.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Elassbli, H., A. Abdelraheem, S. Sanogo, J. Zhang, T. A. Wheeler, V. Kuraparthy. 2017. Evaluation of cotton cultivars and breeding lines for resistance to bacterial blight. Pp. 475-482. Proceedings of 2017 Beltwide Cotton Conferences, Dallas, TX, Jan 4-6, 2017.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Wheeler, T. A., and J. E. Woodward. 2017. Response of new cotton varieties to Verticillium wilt, bacterial blight, and root-knot nematodes. Pp. 251-261. Proceedings of 2017 Beltwide Cotton Conferences, Dallas, TX, Jan 4-6, 2017.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Woodward, J. E., R. J. Roper, and T. A. Wheeler. 2017. Overview of root-knot nematode management options in west Texas cotton. P. 181. Proceedings of 2017 Beltwide Cotton Conferences, Dallas, TX, Jan 4-6, 2017.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Bradshaw, Z, J. Brooks, M. Brown, D. Dunlap, L. Haynes, K. Kowles, T. Mays, T. Millican, D. Nusser, C. Preston, K. Siders, T. Wheeler, and J. Woodward. 2017. Premier cotton education: disease/nematodes 2014-2016. P. 161. Proceedings of 2017 Beltwide Cotton Conferences, Dallas, TX, Jan 4-6, 2017.
    • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Faske, T. R., T. W. Allen, G. W. Lawrence, K. S. Lawrence, H. L. Mehl, R. Norton, C. Overstreet, and T. A. Wheeler. 2017. Beltwide Nematode Research and Education Committee Report on cotton cultivars and nematicide responses in nematode soils, 2016. Pp. 270-273. Proceedings of 2017 Beltwide Cotton Conferences, Dallas, TX, Jan 4-6, 2017.
    • Type: Other Status: Published Year Published: 2017 Citation: Dever, J. K., V. Morgan, C. M. Kelly, T. A. Wheeler, S. Byrd, K. Stair, and J. Arce. 2017. Cotton Performance Tests in the Texas High Plains, 2016. Technical Report 17-1. Texas A&M AgriLife Research, College Station, TX. http://agrilife.org/lubbock/files/2017/02/Cotton-Book-online.pdf.