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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #176355
Title: RELATIONSHIP BETWEEN YIELD POTENTIAL AND PERCENTAGE YIELD SUPPRESSION CAUSED BY THE SOUTHERN ROOT-KNOT NEMATODE IN COTTON

Author
item Davis, Richard
item MAY, O - UNIVERSITY OF GEORGIA

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2005
Publication Date: 9/23/2005
Citation: Davis, R.F., and May, O.L. 2005. Relationship between yield potential and percentage yield suppression caused by the Southern root-knot nematode in cotton. Crop Science. 45:2312-2317.

Interpretive Summary: Currently-available cotton cultivars support significant reproduction of the southern root-knot nematode, but they have not been evaluated for differing levels of yield suppression (tolerance) to this nematode. If nematode tolerant (low yield suppression) but susceptible (high nematode reproduction) cotton cultivars can be identified, they could be grown rather than intolerant cultivars to reduce yield loss. The objective of this study was to evaluate a collection of root-knot nematode-susceptible cotton cultivars for tolerance of parasitism by this nematode. The yield potential and percentage loss to the nematode was measured in 12 genotypes in 2002 and 2003 by comparing yields in fumigated and non-fumigated plots. The percentage yield suppression caused by the nematode differed among cotton genotypes in both 2002 and 2003. Yield suppression ranged from 18.0% to 47.3% in 2002 and from 8.5% to 35.7% in 2003. Though significant levels of tolerance were measured in our study, two years of data on percentage yield suppression document that tolerance is not consistently related to specific cultivars in the absence of nematode resistance. Regression analysis based on the two years of field data revealed a relationship in which percentage yield suppression increased as yield potential increased. Thus, it appears unlikely that cotton cultivar selection for tolerance to M. incognita can be utilized to minimize yield suppression. Increasing yield potential increases the percentage yield suppression in cotton caused by M. incognita. Therefore, because the absolute and percentage losses to nematodes increase as yield potential increases, nematode management becomes increasingly important and beneficial.

Technical Abstract: Currently-available cotton (Gossypium hirsutum L.) cultivars support significant reproduction of the southern root-knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood), but they have not been evaluated for differing levels of yield suppression (tolerance) to this nematode. If nematode tolerant (low yield suppression) but susceptible (high nematode reproduction) cotton cultivars can be identified, they could be grown rather than intolerant cultivars to reduce yield loss. The objective of this study was to evaluate a collection of M. incognita-susceptible cotton cultivars for tolerance of parasitism by this nematode. The yield potential and percentage loss to M. incognita was measured in 12 genotypes in 2002 and 2003 by comparing yields in 1,3-dichloropropene-fumigated and non-fumigated plots. The percentage yield suppression caused by M. incognita differed among cotton genotypes in both 2002 and 2003. Yield suppression ranged from 18.0% to 47.3% in 2002 and from 8.5% to 35.7% in 2003. Though significant levels of tolerance were measured in our study, two years of data on percentage yield suppression document that tolerance is not consistently related to specific cultivars in the absence of nematode resistance. Regression analysis based on the two years of field data revealed a relationship in which percentage yield suppression increased linearly as yield potential increased. Thus, it appears unlikely that cotton cultivar selection for tolerance to M. incognita can be utilized to minimize yield suppression. Increasing yield potential increases the percentage yield suppression in cotton caused by M. incognita. An increase in relative damage as yield potential increases probably also occurs in other crops with other nematodes. Therefore, because the absolute and percentage losses to nematodes increase as yield potential increases, nematode management becomes increasingly important and beneficial.