Effects of Rootstock and Different Irrigation Levels on Yield and Fruit Quality of Apple c.v. Golden Delicious

To evaluate the effects of rootstock and different irrigation levels on quality and quantity of apple fruit, an apple garden in Kahriz Agricultural Research Station was selected to conduct the research plan for four years. The experiment was in a split–block design based on randomized complete blocks with three rootstocks (MM111, M26 and MM106) and three levels of irrigation (100%, 75% and 50% requirement water) in three replications. Results of combined analysis indicated that the effect of year on TSS and annual growth rate was significant at 5% and on yield at 1% levels. The highest TSS rate was obtained in the first year and the highest vegetative growth rate and maximum yield were assessed in the second year .The effect of rootstock on vegetative growth was significant at 5%. The effect of irrigation on TSS and fruit weight was significant at 5% and on vegetative growth rate at 1%. The higest TSS rate was found in irrigation treatment of 50% and maximum annual vegetative growth rate was found in irrigation treatment of 100% water requirement. The highest fruit weight (165.13) was also obtained in irrigation treatment of 100% water requirement. The effects of year and irrigation levels on TSS, yield per tree and per hectare were significant and the hieghest TSS rate was found in 50% irrigation level in the first year. Maximum yield per hectare was obtained in 100% water requirment treatment in the second year. The intraction effects of rootstock in irrigation level on firmness, yield per tree and per hectare were significant. The highest of firmness rate was found in M26 in 100% requirement water. Maximum yield per tree and per hectare was found in M26 in 100% requirement water. Water use efficiency (WUE) increased with decreasing water consumption in all treatments and maximum WUE obtained in 50% water requirement treatment on MM111. In this study M26 and 75% water requirement treatments had better effects on fruit quality and quantity and also on WUE.