Abstract

At the application time of sugarcane ripeners, most times, morning glory plants, that have escaped, survived or emerged, are entwined on sugarcane stalks and these plants are at this time in different reproductive stages (and it becomes more difficult to control) causing a mechanical and crop yield damage. The main aim of this research was to evaluate sugarcane crop ripeners effect on the seeds germination, seedling development and the abscission of the reproductive structures of morning glory. The treatments consist of five ripeners: ethyl-trinexapac (300 ga.i.ha^-1), glyphosate (216 ga.i.ha^-1), fluazifop-p-butyl (75 ga.i.ha^-1), sulfometuron-methyl (15 ga.i.ha^-1), ethephon (480 ga.i.ha^-1) and one control plot (without ripener application). They were applied during the reproductive stages of morning glory. The experimental design used was completely randomized design with four replications and six treatments, to a total of 24 plots. After ripeners application, abscised reproductive structures were counted to determine the percentage of abscission. The seeds of each phenological stage were collected when it reached the point of physiological maturity and it was set to germinate in Petri dishes to evaluate the germination rate, germination mean time, germination velocity, initial growth and dry mass weight. Trinexapac-ethyl, glyphosate and fluazifop-P-butyl application when plants are with open flowers can reduce seed viability. Glyphosate showed the smallest length value and it can affect seedling growth. Glyphosate and ethephon caused the highest percentages of abscission of morning glory reproductive structures and they can contribute to reduce the seeds inflow to the soils.

Key words: Abscission, Ipomoea hederifolia, plant growth regulator, reproductive structure