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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #143976
Title: COTTON BREEDING LINES FROM GEORGIA WITH MODERATE RESISTANCE TO THE ROOT-KNOT NEMATODE

Author
item Davis, Richard
item MAY, O - UNIVERSITY OF GEORGIA
item BAKER, SHELBY - GA AGRIC COTTON COMM

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 1/31/2003
Publication Date: 6/1/2003
Citation: Davis, R.F., May, O.L., Baker, S. 2003. Cotton breeding lines from Georgia with moderate resistance to the root-knot nematode [abstract]. Proceedings of National Cotton Council Beltwide Cotton Conference. p.268.

Interpretive Summary:

Technical Abstract: The Southern root-knot nematode, Meloidogyne incognita, is the most damaging pathogen of cotton in the United States. Resistant cotton could significantly reduce losses. Our objective was to evaluate breeding lines to document resistance and tolerance to M. incognita and to determine if there is a relationship between resistance and tolerance. Reproduction of M. incognita was evaluated on 17 breeding lines, a susceptible control (Delta and Pine Land DP5415), and a resistant control (M-120) in two greenhouse trials. Yield was determined in 2001 and 2002 in fumigated (Telone II, 1,3-dichloropropene at 6 gal/acre) and non-fumigated plots in a strip-plot design. Eight lines had less (P<0.05) nematode reproduction than the susceptible control, with reductions ranging from 45 to 57%. Reproduction on the resistant control was reduced 90%. The eight resistant genotypes had similar levels of M. incognita reproduction, and none of them were as resistant as M-120. The amount of yield suppression caused by nematode infection differed among genotypes (P<0.05). Three genotypes had no difference in yield between the fumigated and non fumigated plots (P<0.10)in either year. Two of these also were resistant to M. incognita. Regression analysis found that yield suppression decreased linearly as nematode resistance increased. We have developed two breeding lines (GA96-100 and GA96-211) with acceptable yields that support less M. incognita reproduction than susceptible cultivars and suffer significantly reduced yield loss in M. incognita infested fields.