Tolerância de cultivares e linhagens de feijão-caupi ao herbicida Imazamox

Abstract

This work was carried out with the objective of evaluating the tolerance of cowpea cultivars and lines to the application of imazamox in post-emergence. The experimental design was randomized blocks in a split plot with four replications. The cultivars BRS-Itaim, BRS-Guariba, BRS-Imponente, BRS-Novaera, BRS-Pajeú, BRS-Tumucumaque and the lines CO3, FR22, FR26, IN11, IN35, IN49 were evaluated. Visual phytotoxicity scores were assigned at 7, 14, 21 and 28 days after application (DAA) on a scale from 0 to 100%. The number of plants per meter, the number of pods per plant, number of grains per pod, weight of 1000 grains and yield were evaluated. Analysis of variance was performed with comparison of means using the Tukey test at 5%. At 28 DAA, the genotypes with the highest phytotoxicity from the herbicide imazamox were cultivars BRS Guariba and BRS Itaim and lines FR22 and FR26, although phytotoxicity was lower than 17% in all genotype. There was a reduction in plant stands only in the cultivar BRS Novaera, in mass of 1000 grains in the cultivar BRS Imponente and in pod length in the lines FR22, IN11 and IN35, although the reduction in relation to the control was less than 13% for these variables. There was no herbicide effect on the number of grains per pod, pods per plant and crop yield. It is concluded that the evaluated cowpea cultivars and lines are tolerant to the herbicide imazamox.