Tolerância de genótipos de feijão-caupi em estádio inicial ao herbicida Fomesafen

Abstract

Weeds can cause large reductions in grain yield in cowpea crops and few herbicides are registered for their management. The objective of this work was to evaluate the tolerance of different genotypes of cowpea to the herbicide fomesafen. The experiment was carried out in a greenhouse at Embrapa Agrossilvipastoril, Sinop-MT. The experimental design was in randomized blocks, in a factorial scheme 20 x 2 with 3 repetitions. The treatments consisted of a combination of 20 genotypes (IN-11, IN-14, IN-19, IN-23, IN-35, IN-47, IN-49, IN-70, CO- 3, CO-12, FR-21, FR-22, FR-26, FR-28 and the cultivars BRS Itaim, BRS Novaera, BRS Imponente, BRS Tumucumaque, BRS Guariba and BRS Pajeú) and herbicide application (with and without the application of fomesafen) . The evaluation of phytointoxication was carried out at 7, 14, 21 and 28 days after application, using the visual method on a scale of 0% to 100%, where 100% represents the death of the plant and 0% the absence of symptoms. Then, the aerial part close to the ground was removed for evaluation of dry matter mass and relative dry matter mass. The results obtained were subjected to analysis of variance with comparison of means by the Scott-Knott test at a 5% probability level. The BRS Guariba, BRS Pajeú, BRS Novaera, BRS Tumucumaque, BRS Itaim, CO-12, CO-3, FR-21, FR-22, FR-26, FR-28, IN-14, IN-19, IN genotypes -23, IN-35, IN-49, IN-47 and IN-70 are more tolerant than BRS Imponente and IN-11 to the herbicide fomesafen.