Growth retardant and nitrogen levels in wheat agronomic characteristics.

Facing the use of high rates of nitrogen (N) fertilizer in wheat crop, the importance of the use of plant growth regulators is observed, and it has become important technology to improve the production effi­ciency of various species of plants. Thus, we aimed at evaluating the effect of N fertilization, with Sulfammo ® , and the use of growth reducer on the agronomic traits of wheat cultivars. The work was conducted in the experimental area of the Federal University of Santa Maria, Frederico Westphalen campus, in the period from 06 June to 20 October 2012. The soil in the area is classified as dystrophic Red Latosol and the experimental design was a randomized complete block in a 3x5x2 factorial, with three cultivars (TBIO Mestre, TBIO Iguacu e TBIO Itaipu), five rates of N (0, 40, 80, 120 and 160 kg ha -1 ) and application or not of growth reducer (trinexapac-ethyl) at a dose of 100 g ha -1 , with three replications. The growth reducer reduces the length of the second and third internode to the TBIO Itaipu and TBIO Iguacu, the total biomass of the plant, increases thousand grain weight and increases the number of spikelets per spike in TBIO Itaipu. Increasing the rates of N as Sulfammo® allows increasing the length of the first, second and third internodes, culm length, ear length and mass of the spike.