Resistência genética de genótipos de algodoeiro de fibra colorida ao nematóide Rotylenchulus reniformis

Abstract

The resistance of a plant is the ability of a species or variety to reduce the action of a pathogen, that is, the ability of the plant to delay, suppress, or prevent the action of a pest or its entry into the plant. One way to obtain resistance is through genetic improvement, where desired genes are obtained through crosses. The objective of the study was to evaluate the resistance level of different genotypes of cotton (Gossypium hirsutum) to the nematode Rotylenchulus reniformis. The experiment was conducted in Uberlândia, in randomized blocks, in a greenhouse, and the evaluated characteristics were: 1) plant height, 2) leaf area, and 3) number of nodes, assessed at 30, 60, and 90 DAE (Days After Emergence), 4) number of nematodes per gram of root, and 5) reproduction factor, evaluated at 90 DAE. Two genotypes of colored cotton (UFU 11, UFU 17) and six commercial cultivars (DP 1552, IMA 8405, TMG 82, IMA 58, TMG 47, BRS 433) were used. The results showed significant differences among the genotypes regarding plant height, leaf area, number of nematodes per gram of root, reproduction factor, and number of nodes. There was a significant interaction between genotypes and time for the number of nodes. There were no statistical differences in diameter among the cultivars. None of the evaluated genotypes showed resistance to R. reniformis. The genotypes DP 1552 and TMG 82 showed potential in terms of nematode reproduction factor.