eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-03-11 5 2 515 524 7121 article Abdellah Akhkha 1 Biology Department, Faculty of Science, Taibah University, Madinah Munawwarah, (Kingdom of Saudi Arabia). The compensatory photosynthesis in uninfected fourth leaf of infected plants was investigated in cv. Prisma and the two wild lines B19909 and I-17-40. Infection of the three lower leaves increased the rate of photosynthesis as well as the quantum efficiency in the powdery mildew tolerant line B19909 only. This indicates that compensatory photosynthesis may play an important role in tolerance of the parasite. https://www.biotech-asia.org/vol5no2/the-effect-of-powdery-mildew-blumeria-graminis-f-sp-hordei-on-compensatory-photosynthesis-and-dark-respiration-in-the-uninfected-fourth-leaf-of-infected-cultivated-and-wild-barley-lines/ Blumeria graminis; compensatory photosynthesi; wild barley lines