Morphological and agronomic evaluation of red beans (Phaseolus vulgaris L.) ecotypes under drought conditions

Drought stress is a major cause of damage to crops throughout the world by reducing the yield by 50 percent. Drought stress when increases that the high evaporation capacity of leaves be higher than the ability of roots to absorb water from the soil. Considering that Iran is in the arid and semi-arid of world, at this areas there is a lot of rain fluctuations and there may be some important stages of plant growth due to water shortage be confronted by reduce soil water potential. Beans (Phaseolus Vulgaris L.) are an important source of food around the world that has a high nutritional value because of protein, fiber and vitamins in grains. This plant is considered a major source of vegetable protein in many developing countries. Reduce the effect of environmental stresses using methods such as irrigation, fertilizer and appropriate methods of planting in these areas is limited. Therefore, genetically breeding plants to minimize environmental stress is worth the effort. Considering the importance of legumes and drought stress, the aim of this study was to identify the tolerant and susceptible bean cultivars using morphological and agronomic traits under drought stress condition and also identify desirable traits be to select tolerance cultivars.
For evaluation the reaction of twenty Red beans ecotypes to drought stress an experiment was conducted in split plot of Randomized Complete Block Design with 3 replications cropping years (2016-2017) at research field of Graduate University of Advanced Technology, Kerman, Iran. In this study, the main plots were three irrigation levels and sub-plot were twenty Red beans ecotypes. After applying the treatments and harvesting time morphological and agronomic traits such as stem height, number of lateral branches, number of pods per plant, seeds per pod, pod infertile, pod length were measured and economic performance. In addition, the weight of the bushes after harvesting and drying, the scales were identified. Analysis of variance and mean comparison of traits was done by SAS software.
The results of variance analysis of traits were showed significant difference between stress levels and between cultivars for all studied traits. In studied red beans ecotypes, the Dhzarchy and Hassan Abad ecotypes had the largest stem height, while Baft ecotype was lower stem height. Most and lowest plant dry weight Obtained from ecotype Mahan (28.27 g) and DashtAb ecotype (15.51 g), respectively. Also, the maximum length pods related to DashtAb ecotype and the lowest be related to the ecotype Bardsir. Economic yeild is affected by water stress applied in the experiment were significantly lower. Studied ecotypes showed significant differences in terms of yield, this may be the result of the effects of water shortages on their yield components.
Conclusions ;According to archived results of mean comparisons, Ghazvin, Mahan, Hasan Abad and Dehzarchi were the most tolerant cultivars and Baft was the most sensitive cultivar. So, it seems that these tolerant cultivars are suitable for direct culture in farm that has limitation for irrigation. Also ecotype Baft in most traits had lower values than other ecotypes which can be considered this ecotype as the most sensitive ecotypes. Totally recommended tolerant ecotypes directly planted or that these ecotypes were crossed to susceptible ecotypes to create a new variety.