Effects of Water Deficit and Shading on Morphology and Grain Yield of Soybean (Glycine Max L.)

A split plot experiment on the basis of randomized complete block design in three replicates was conducted to investigate changes in some morphological traits and grain yield of soybean (Glycine max L.). Treatments were irrigations (I1, I2, I3, I4: irrigation after 60, 90, 120 and 150 mm evaporation from class A pan, respectively) in main plots and light interceptions (S1, S2, S3: 25, 65 and 100% of sunlight) in sub-plots. Plant height was significantly reduced by severe water stress, compared to the well watered plants. In contrast, stem diameter increased by decreasing water deficit. Shading increased soybean plant height and decreased stem diameter. Although, leaves per plant and grain yield per unit area decreased with increasing shading under I1 and I2, they were increased as light interception decreased under I3 and I4. This is an advantage for shaded plants to enhance leaves per plant and grain yield per unit area under limited water availability.