Effect of defoliation on bean yield

The purpose of this study was to correlate loss of yield with percentage of leaf area removed in different stages of bean plant. The cultivars used were Rosinha G2 (type II) and Carioca (type III), evaluating four levels of defoliation (0, 33, 67 and 100%), applied in five developmental stages. The analysis of yield showed that the losses increased proportionally to the levels of defoliation, reaching 59% when the cultivars were submitted to 100% defoliation. Even though the effects on yield were linear, the reductions in the leaf area up to 33% resulted in an average loss of only 5.6% in bean yield. Regarding the yield components, the number of pods per plant was the most affected, showing, for the level of 100% of defoliation, reductions of 45.1% and 42.0% for the cultivars Carioca and Rosinha, respectively.