Abstract

Genetic increase in bean yields in dry areas has not been as great as in more favorable environments. Plants with their ability to change morphologically and physiologically are able to continue their existence in regions where there is not enough rain and soil humidity is low. In order to assess some of these changes, the relationship between proline content, potassium ion and the relative water content with the yield and yield components of bean genotypes under drought stress, an experiment in formed split plot design in a randomized complete block design with three replicates was performed in the research field of the Azad Islamic university of Shiraz. The main plot consisted of irrigation surfaces (well-watered and drought stress) and the sub plot consisted of three white bean genotypes. Data were statistically analyzed with the help of computer facilities and Statistical Analysis System (SAS) program. The results revealed that the effect of irrigation was significant in most characteristics (except the weight of 100 grain and harvest index). A significant difference was seen between the lines regarding the total character (except biomass). The interaction of irrigation surfaces × genotype also showed a significant difference for characteristics such as number of pods in the plant, weight of 100 grain, harvest index, the seed yield of single plant and the potassium ion content. The obtained results showed that the accumulation of more potassium and proline in beans under drought can be a kind of adaptation for tolerating dryness, which can in turn help the plant to survive and reproduce under drought conditions.

Key words: Drought stress, white bean, relative water content, proline content, potassium ion.