TRINEXAPAC-ETHYL REDUCES PLANT HEIGHT AND SEED YIELD IN FORAGE SORGHUM

Forage sorghum presents tall plants, what makes mechanicalseed harvesting a difficult task. Plant hormones can reduce plant height andfacilitate the harvesting. Thus, the objective of this study was to evaluatethe effect of the growth regulator trinexapac-ethyl on plant height and seedyield in forage sorghum. This research was carried out at Embrapa Maizeand Sorghum, in two seasons (2017 and 2018), in a randomized completeblock design, four replications and three varieties (BRS Ponta Negra, 1141574and 0947216) under application of Trinexapac-ethyl in two stages of the plantgrowth (V8, V12, V8 + V12). The characteristics evaluated were: plant height,seed yield and mass of 1000 seeds. The effect of the hormone was significantin both stages of growth, with a significant reduction in plant height. Thehormone applied twice at growth stages V8 + V12 had a greater effect inreducing plant height. However, the hormone reduced seed yield in the threevarieties, what implies the need for further studies comparing the advantageof plant height reduction and the loss in seed yield.