2008 Annual Report
Research efforts to incorporate useful levels of resistance to reniform nematode into upland cotton are underway. Breeding efforts are continuing with the goal of transferring moderate levels of reniform nematode resistance from less-adapted day-neutral Texas race stock lines into commercially desirable lines. A multi-year experiment evaluating the impact of selected day-neutral Texas race stock lines on reniform nematode population levels in the soil has been established and is in its second year. In addition, the gene for reniform nematode resistance from LONREN-1 was transferred into Mid South adapted breeding lines. Progeny with the resistance gene are being identified using molecular marker BNL 3279. Work to transfer genes for resistance to reniform nematode into upland cotton from its distant relatives (objective.
Efforts to identify cotton varieties that are tolerant to reniform nematode are continuing in field trials. Twelve cotton lines are being evaluated for the second year in a reniform nematode infested field by comparing nematode counts and seed cotton yields of each cotton line in untreated plots and plots treated with a nematicide. Lines reported to be tolerant to reniform nematode are being used as parents in crosses. Research to identify cultural and chemical methods that can minimize losses to reniform nematode is continuing. Crop production practices including tillage, irrigation, early planting, and nematicides are being evaluated in field trials. Several years will be required to complete these experiments. The ability of common Mississippi weeds to support growth and reproduction of reniform nematode is being assessed in greenhouse tests. Field trials are in progress to determine the effectiveness of newly registered and experimental nematicide seed treatment combinations such as Aeris and Avicta. Some research is being done in cooperation with scientists at other institutions. Research in objective 4 is being conducted by Mississippi State University scientists under a Specific Cooperative Agreement between ARS and the Mississippi Agricultural and Forestry Experiment Station (6402-22000-005-01S). Scientists at Pasteuria Bioscience and ARS researchers are working to identify bacteria that may work as a biological nematicide under a Specific Cooperative Agreement (6402-22000-005-04S) in support of objective 4. Scientists at Texas A&M University are cooperating on research listed in objective 2 under a Non Funded Cooperative Agreement between ARS and Texas A&M University (6402-22000-005-03N). Separate reports summarize work completed under these agreements.
5.Significant Activities that Support Special Target Populations
Stetina, S.R., Young, L.D., Pettigrew, W.T., Bruns, H.A. 2007. Effect of Corn-Cotton Rotations on Reniform Nematode Populations and Crop Yield. Nematropica. vol. 37:237-248
Sacks, E.J. 2008. Ovule Rescue Efficiency of Gossypium Hirsutum x G. Arboreum Progeny from Field-Grown Fruit is Affected by Media Composition and Antimicrobial Compounds. Plant Cell Tissue And Organ Culture. DOI 10.1007/s11240-007-9316-2.
Abel, C.A., Adams, L.C., Stetina, S.R. 2007. Sweet Potato Yield Reduction Caused by Reniform Nematode in the Mississippi Delta. Plant Health Progress. 10:1094/PHP-2007-1115-01-RS.