evaluation of some physiological and morphological characteristics of three apple cultivars onto vegetative rootstocks, mm106, mm111 and m9

rootstock and cultivar selection is the most critical decision at the time of an apple orchard establishment. tree size, yield and fruit quality are affected by roostock and cultivar. non-sufficient study of rootstocks and cultivars effects on mentioned traits will lead to incorrect result or failure in orchard managing. in this study the effects of three vegetative rootstocks (mm106, mm111 and m9) on vegetative and reproductive growth and some physiological characteristics of three apple )malus domestica borkh.( cultivars, ‘golden delicious’, ‘fuji’ and ‘delbarestival’ were evaluated in a factorial experiment based on randomized complete block design in khodabande (zanjan province) during two growing seasons in 2011 and 2012. the results showed that different combinations of rootstock and cultivar have significant effects on vegetative vigor, primary and final fruit set, yield per tree and yield per hectare, amount of fruit dry weight, leaf photosynthesis rate, stomatal conductivity and transpiration rate, water use efficiency and leaf soluble carbohydrates. in two years of study, ‘golden delicious’ and ‘fuji’ cultivars had the highest and lowest fruit length, respectively. the highest trees were observed in ‘delbarestival’ cultivar. among the evaluated rootstocks, the lowest tree canopy diameter was measured in m9 rootstock. nitrate reductase activity was affected by cultivar and rootstock and the highest activity of this enzyme was measured in leaves of ‘golden delicious’ cultivar grafted on m9 rootstock. ‘delbarestival’ onto mm106 rootstock and ‘golden delicious’ onto m9 rootstock were the most appropriate grafting combination based on the studied traits in this research .