Resposta de cultivares de arroz a doses de nitrogênio e do regulador de crescimento cloreto de clormequat

Abstract

The objective of this work was to evaluate N rates (0, 50, 100 and 150 kg ha-1) and the growth regulator chlormequat chloride effect (0, 1 e 2 L ha-1) on some agronomic characteristics of rice cultivars IAC 201 and IAC 202. The experimental design was a randomized block with four replicates. Nitrogen was applied as side-dressing at flower differentiation and the growth regulator was split in two times and applied at 20 and 30 days after seedlings emergency (tillering). In the harvests of 2001/2002, there was no significant effect of N rates on plant height, panicle length, spikelet per panicle, 100-grain mass and grain yield. The growth regulator rates were significant for panicle length and spikelet per panicle. IAC 202 presented higher grain yield. In the harvest of 2002/2003 there was no effect of N rates on plant height, spikelet fertility, 100-grain mass and grain yield. The growth regulator rates had no effect on tested characteristics, and IAC 202 cultivar presented higher grain yield.