Glufosinate, nicosulfuron and combinations in the performance of maize hybrids with the pat gene

Abstract

Combinations of glufosinate with nicosulfuron, among other post-emergent herbicides, are promising for weed control
in maize. However, some of these herbicides can cause injury and have other undesirable effects on the maize, so it is necessary
to investigate their selectivity for cultivation. The aim of this study was to evaluate the selectivity of glufosinate, nicosulfuron and
combinations, by analysing the agronomic performance of the crop for post-emergent application in maize hybrids with the pat gene.
Two experiments were conducted in the state of Paraná, Brazil, during the 2019/2020 season, in a 2 x 8 (exp. I) and 2 x 4 (exp. II)
factorial scheme. Two hybrids were used (FS505 PWU and FS715 PWU), with eight levels for the factor herbicide in experiment I
(glufosinate, halosulfuron and glufosinate in combination with halosulfuron, nicosulfuron, atrazine, tembotrione or mesotrione, in
addition to the control with no application) and four levels of herbicide in experiment II (nicosulfuron in two formulations, mesotrione,
and the control). Injury to the maize plants and variables related to agronomic performance were evaluated. Although the herbicides
had no effect on yield, it can be inferred that FS505 is more sensitive to nicosulfuron and mesotrione than is FS715, since the injury
was greater than seen in FS715. The post-emergent application of glufosinate, nicosulfuron and combinations is selective for the FS505
PWU and FS715 PWU hybrids (with the pat gene). Despite injury, which was more pronounced in the FS505 PWU hybrid, there was
no negative impact on yield or on other the variables of agronomic performance.