The work was carried out at the Federal University of Santa Maria, State of Rio Grande do Sul, in 1997/1998 using the cultivar BR 16. Statistical setup was a block design with sub-divided plots, with 4 replications. The objective of this research was to evaluate the yield of the soybean variety BR16 when submitted to different defoliation levels (0, 17, 33, 50, 67 and 100%) and at different phases of development (V9, R3, R5 and R6) in agreement with the scale of FEHR & CAVINESS (1977). The defoliation levels of 17, 33 and 50% decreased seed yield by approximately 6% and the last two levels 67 and 100%, by about 8 and 37% in relation to 0% of defoliation. Levels of defoliation above 50% decrease the number of normal pods substantially and grains for plant when made at the beginning in the stadiums of formation of the pods (R3) and beginning of the formation of grains (R5). The reduction of grain yield was effected by the number of normal pods number of normal grains and weight of 100 seeds, which were the components most effected by the treatments.
artificial desfoliation; soybean
