WHEAT RESPONSES TO STRESSES CAUSED BY LOW -LIGHT INTENSITY AND WATER EXCESS IN THE SOIL .2. FIELD TESTING

The experiment was carried out in the field at the Agronomic Experimen tal Station of the Federal University of Rio Grande do Sul, in Brazil. The objective of this work was to assess the effect of stresses cause d by water excess in the soil and by light reduction on 12 wheat (Trit icum aestivum L.) genotypes. It was observed that the stress caused by shading, with 40% light reduction, caused significant modifications i n agronomically important characters, like plant stature, number of fe rtile tillers per plant, peduncle length, number of fertile spikelets per spike, maximum number of grains per spikelet, plant weight and gra in weight per plant; moreover, it increased the number of sterile spik elets per spike. The reductions caused by water excess in the soil wer e less significant to wheat as compared to the ones caused by shading, mainly as a result of environment conditions over cropping period.