Root-Knot Nematode Effect on Nine Cotton Cultivars in Mississippi1
- Earl B. Minton and
- William R. Meredith2
Lint yields of cotton (Gossypium hirsutum L.) in the USA have decreased since the mid-1960s even though new cultivars developed during this period are more productive than the cultivars they replaced. Nematodes have been suspected of being a factor in declining yields. This field study was designed to compare the performance of nine cotton cultivars when grown in fumigated and nonfumigated soils (Typic Dystrochrepts). The target nematode species was the root-knot nematode, Meloidogyne incognita (Kofoid & White) Chitwood, and the fumigant was 92% 1,3-dichloropropene (Telone II3). Seedling survival and plant height were not affected significantly by soil fumigation. Numbers of second stage root-knot nematode juveniles in soil samples and root-gall indices of cotton cultivars were reduced by fumigation with Telone II. The greatest reduction in root galling occurred on nematode-susceptible cultivars. Telone II reduced lint yield of ‘Delcot 311’, ‘Auburn 56’, and LA 434 RKR from 1 to 4%. The latter two are the most tolerant to root-knot nematode of the cottons tested. Lint yields of the more susceptible cultivars were increased from 2 to 6% by Telone II. Regression analysis of the yield differences between nonfumigated and fumigated treatments on the root-knot indices of the cultivars grown in the nonfumigated plots showed that M. incognita reduced lint yields 35.7 kg ha−1 for each unit increase in root-gall index.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 1987.