Evaluation of the Relationship of Shading with Growth and Grain Yield of Faba Bean

In many plants, shading affects growth characteristics and yield due to the reduction of solar radiation. On this basis, two experiments were carried out at the Research Farm of the University of Tabriz (Latitude 38.05´N, Longitude 46º17´E, Altitude 1360m above sea level) in 2002 and 2003. Both experiments were split-plot, based on randomized complete block design in three replications, with the shading treatments in main plots and cultivars in sub-plots. Shading treatments consisted of no shade (control), 18%, 48% and 70% shade and varieties were Barakat, Saraziri and HBP-B. Results showed that in the most stages of growth (particularly later stages), Dry matter accumulation (DMA), crop growth rate (CGR), and relative growth rate (RGR) were higher for plants under shade, compared to plants under full sunlight. Mean grain yield of faba bean per unit area for shaded plants was higher than that for unshaded plants. HBP-B had higher grain yield per unit area in comparison with other cultivars. Therefore, faba bean as a shade resistant plant can be successfully used in intercropping and agro forestry.