effect of naa and certain treatments on sprout control and growth in citrus nursery trees

suckers are strong sinks of water and nutrients, thus they have intensive competition with plant vegetative parts like scion of budded seedlings. this is an enormous problem of citrus nurseries in north of iran. as far as vast input and time is spending on control of these unwanted suckers. this research, that carried out in design, compares 10 different sucker control methods in three citrus rootstocks (troyer citrange, sour orange and citromelo) with five replications. mean comparison of variables show that naa with 2500ppm in twentieth day after budding and also aluminum foil treatment could control the suckers in respect to sucker number, length and leaf number, significantly better than other methods. fresh weight of sprout in nursery trees without sucker removal treatments was the highest. in this variable, all naa treatments, aluminum foil and two month manual removal, without significant difference, reduced the weight of suckers. evaluation of variables related to scion vegetative growth indicate length, leaf number, total leaves surface and fresh weight of scion, in all sucker control treatments were significantly less than complete manual removal method. scion performance was delayed significantly in high concentration of naa (2000 and 2500ppm in twentieth day after budding).