Submitted to: Nematropica
Publication Type: Abstract Only
Publication Acceptance Date: 7/21/2003
Publication Date: 8/21/2003
Citation: ROBINSON, A.F., GAZAWAY, W.S., MCGAWLEY, E.C. RESISTANCE TO ROTYLENCHULUS RENIFORMIS IN FOUR GOSSYPIUM SPECIES MASKED BY NEMATODE SURVIVAL IN TEXAS, LOUISIANA, MISSISSIPPI, AND ALABAMA. NEMATROPICA. 2003. V. 33: ABSTRACT P. 30.
Technical Abstract: Upland cotton supports prolific reproduction by Rotylenchulus reniformis and agronomists are convinced the nematode is causing major losses in the central part of the United States cotton belt. Several breeding projects are trying to introgress resistance from four Gossypium species. Resistance observed previously only in the greenhouse was suppressed in the first field test in Texas in 2001, and subsequent micro plot and growth chamber experiments indicated nematode genetics was not a factor. Therefore, the hypotheses was tested in 2002 that resistance suppression was site-independent by planting susceptible controls and nine resistant accessions of G. arboretum, G. barbadense, G. herbaceum and G. longicalyx in parallel tests in Alabama, Mississippi, Louisiana, and Texas. Nematode per gram soil and nematodes per centimeter root were measured at harvest time at 15 cm increments down to 120 cm. High population densities occurred under all accessions but high densities also occurred under fallow and when these were subtracted from those in other plots, the primitive accessions appeared resistant with relative differences similar to the greenhouse. Thus, high survival by R. reniformis masks resistance in cotton and future resistant cultivars likely will not give high yields in infested fields the first year.