Water Stress Effects on Two Common Bean Cultivars with Contrasting Growth Habits

In most rainfed production areas in Iran, where wheat fallow is common, crop yield and resource sustainability could be improved by changing to more diverse crop rotation. It seems necessary to identify crop cultivars suitable for such diversification. This study was aimed to determine responses of two common bean (Phaseolus vulgaris L.) cultivars with different growth habits (Sayyad as an indeterminate and D81083 as a determinate cultivar) to water stress conditions. The study was conducted in controlled conditions (the greenhouse of Department of Crop Production and Plant Breeding, College of Agriculture Shiraz University, Shiraz, Iran) during 2008 growing season. There were four water stress levels (100, 75, 50 and 25% of field capacity by weight). The results showed that plant height, number of leaves, leaf area, number of pods, pod dry weight and total dry weight of both cultivars responded significantly to water stress conditions. Water stress also reduced stem height and reduced leaf area. Furthermore, it reduced pod dry weight in both cultivars and in 50 and 25% water stress levels, all plant pods of both cultivars were aborted. Common bean cultivar with determinate growth habit (D81083) appeared to have potential as a dryland rotation crop for arid areas with dryland farming. Further field research might shed more light on sensitivity of bean cultivars to water stress levels with the aim of crop diversification for dryland areas in Iran, where adequate moisture supply is limiting.