TORKANPASSNING HOS UTVALDA GENOTYPER AV DEN VANLIGA BÖNAN UNDER UPPREPAD TORKA

Abstract

The common bean (Phaseolus vulgaris) is globally, one of the most consumed legumes and is great source of various important nutrients, especially in many developing countries. Rwanda in Africa relies heavily on the common bean, and more than half of their protein intake comes just from them. Therefore, a lot of resources is put to into improving the existing genotypes. An unavoidable challenge is the ever-increasing global temperatures. Not only does the average temperature increase, but the precipitation patterns will shift and change, which causes a different water availability in many regions. A typical response in plants to less water availability is to partially, or fully close the stomata which reduces the amount of transpiration. An ability to regulate this response is consequently very important to make sure the plant does not use all the available water until the next rainfall comes. The purpose of this study was to investigate differences in acclimation between repeated periods of drought in some picked genotypes of the common bean, which have an origin from Rwanda. This was tested by weighing the bean plants daily from the last watering at experiment start, until they visibly looked withered to calculate the speed of water loss. When most individuals of a genotype showed clear signs of withering, they were rewatered, and the procedure was repeated until there is a total of three cycles of withering for each genotype. In addition, the leaf area was measured after each watering because the area will affect the total possible transpiration. Statistical analysis was also done to determine if there is a difference between the genotypes speed of water loss at certain time intervals. A difference could be found between the genotypes, but its reliability was considered low because of low number of replicates inside the genotypes and the sheer number of genotypes tested. There were however a few genotypes that clearly stood out from the rest. A significant difference could also be found in the speed of water loss between the withering cycles, which indicates there is some form of response to the repeated drought. An experiment with fewer genotypes and more replicates would most likely give a more reliable result from the statistical tests that were done.