Relationship between yield potential and percentage yield suppression caused by the southern root-knot nematode in cotton

• Published in: Crop science 2005-11, Vol.45 (6), p.2312-2317
• Main Authors: Davis, R.F, May, O.L
• Format: Article
• Language: English
• Subjects: Agricultural production; Agronomy. Soil science and plant productions; Biological and medical sciences; Cotton; crop yield; Cultivars; fiber crops; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; genotype; Genotypes; germplasm; Gossypium hirsutum; Meloidogyne incognita; Nematodes; Parasitism; Pest animals; Pest resistance; Phytopathology. Animal pests. Plant and forest protection; Plant nematodes; plant parasitic nematodes; plant pests; Protozoa. Invertebrates; Records, symptoms, damages, economic importance, population surveys; Regression analysis; Varietal selection. Specialized plant breeding, plant breeding aims; Yield; yield losses; yield potential
• ISSN: 0011-183X; 1435-0653
• DOI: 10.2135/cropsci2005.0038

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 to parasitism by this nematode. The yield potential and percentage yield loss to M. incognita were measured in 12 genotypes in 2002 and 2003 by comparing yields in 1,3-dichloropropene-fumigated and nonfumigated 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, 2 yr of data on percentage yield suppression show that tolerance is not consistently related to specific cultivars in the absence of nematode resistance: susceptible cultivars did not consistently express tolerance, but resistant germplasm did. Thus, it appears unlikely that cotton cultivar selection for tolerance to M. incognita can be utilized to minimize yield suppression. Regression analysis based on the 2 yr of field data revealed a relationship in which percentage yield suppression caused by M. incognita increased linearly as yield potential increased. Because the absolute and percentage losses to nematodes increase as yield potential increases, nematode management becomes increasingly important and beneficial in cotton.