Growth regulator on oat yield indicators

ABSTRACT Growth regulator in oat can reduce lodging with effects on yield indicators. The objective of the study is to define the optimum dose of growth regulator to reduce lodging in oats under different conditions of nitrogen (N) fertilization (reduced, high and very high) and the effects on yield indicators in the succession systems. In each succession system (soybean/oats and corn/oats), two experiments were conducted, one to quantify biomass yield and the other to estimate grain yield and lodging. In the four experiments, the design was randomized blocks with four replicates in 3 x 4 factorial scheme, for N-fertilizer doses (30, 90 and 150 kg ha-1) and growth regulator doses (0, 200, 400 and 600 mL ha-1), respectively. Growth regulator reduces lodging in oat plants, with the ideal doses of 500 mL ha-1 in the soybean/oat system and 400 mL ha-1 in the corn/oat system, regardless of the reduced, high and very high N doses. There is a linear reduction of biological and straw yields, and a quadratic trend in the expression of grain yield and harvest index as a function of the growth regulator doses, regardless of succession systems (soybean/oats and corn/oats).