03036naa a2200253 a 450000100080000000500110000800800410001910000210006024500830008126000090016430000110017352022180018465000110240265000230241365000260243665000090246265300110247165300280248265300120251070000170252270000220253970000220256177301990258314617382004-10-15       1999    bl uuuu     u00u1 u    #d1 aFARIAS, J. R. B.  aEffects of water deficits during different phases of soybean crop development.  c1999  ap.601.  aThe variability in yield and grain quality among years in the same location and sowing time are intimately related to the water availability. Water deficit effects on yields are variable as a function of intensity and duration of the deficit and the stage of plant development. The objective of this work was to compare yield, its components and oil and grain protein content of plants submitted to water deficits during the vegetative and reproductive periods to the ones produced without water restrictions (irrigated). The experiment was carried out in the field at the Experimental Station of EMBRAPA's National Soybean Research Center, in Londrina, PR, Brazil. The soil moisture was monitored with tensiometers and a neutron probe. Rainfall over the plots was controlled with mobile shelters that automatically covered/stopped the plots when the rain started/stopped. When necessary, irrigation was supplied according to the treatments to attend crop water needs. Yield reductions of 75% were observed when water deficits were applied during the reproductive period as compared to treatments without water restrictions. With water deficits during the vegetative period, the reduction in yield was 55%. The lack of water during the reproductive phase caused a smaller number of seeds per pod and a larger seed weight. These variables were not significantly different when compared to the two other treatments (water deficit during the vegetative phase and irrigated). The number of pods per plant was higher without water restriction and lower with water deficit during the reproductive phase. The higher grain oil contents were observed in treatments with no water restriction and the highest grain protein contents were found in plants submitted to water deficit during the reproductive phase. Grain protein content was lower in plants without water restriction. Water deficit during the vegetative phase produced the lowest grain oil content. This was observed in all cultivars tested. It can be concluded that, although soybean fields grown under low water availability during the reproductive period produce reduced yields, the grains have higher protein content, and can be directed to specific markets.  aBrazil  asoil water deficit  aDeficiência Hídrica  aSoja  aBrasil  aDeficit de agua no solo  aSoybean1 aNEUMAIER, N.1 aNEPOMUCENO, A. L.1 aBORDINGNON, J. R.  tIn: WORLD SOYBEAN RESEARCH CONFERENCE, 6., 1999, Chicago. Proceedings: invited and contributed papers and posters. Chicago: University of Illinois / Soybean Research & Development Council, 1999.