Publicação on-line; 17 ref.; 3 tables; 3 illus.; Summary (En)

ABSTRACT
Background: The resistance of weeds to herbicides is a problem that
has been increasingly studied because of its great importance in
agriculture and rapid growth of this phenomenon worldwide. The quick
detection of resistant plants is extremely important for resistance
management. Weed resistance to herbicides can be detected through
field, greenhouse and laboratory tests. A fast way of detecting resistance
is using tissue culture method, where is possible to use resistant
plant clones and obtain results faster than whole-plant method in
greenhouse.
Objective: The aims of the research were to detect the resistance of
blackjack to herbicides inhibitors of the acetolactate synthase (ALS),
addition in vitro cultivation; determine the herbicide concentration of
imazethapyr to 95% control of the susceptible plant population; evaluate
explants growth; and, determine the herbicide concentration added to the
culture medium where is possible to distinguish a resistant from a
susceptible plant.
Methods: Experiments were carried out in greenhouse and tissue culture
laboratory. Screening was performed to select resistant and susceptible
biotypes, tests for specie establishment and dose response curves in vitro
were made.
Results: The herbicide concentration added to the culture medium that
provided 95% susceptible biotype control and efficiently differentiated
susceptible biotype from resistant one was 0.6μM of imazethapyr.
Conclusions: This method helps recommendations of weed
management and provides a quick decision to alternative control of this
specie, thus avoiding major damage to the crops

Keywords:
Bidens Pilosa
resistance test
acetolactate synthase
weed.