Effects of some plant growth regulators on some biometric variables in mango cv. 'Haden'

An experiment was designed to evaluate the influence of Paclobutrazol (PBZ) alone or combined with Ammonium thiosulphate (ATS) and Potassium thiosulphate (PTS) on mango 'Haden' trees. Plants were of nine years of age and located at the College of Agriculture Experimental Station, situated at 10 degrees 16' 13' N and 67 degrees 36' 41' W, and at 450 masl. The experimental design used was an incomplete randomized block with five replications, and one tree represented the experimental unit. The treatments were : Check (To), PBZ only (T1) and the combinations of PBZ plus ATS or PTS; the ATS and PTS at three different concentrations, and at two different application time. The biometric variables measured were : plant height (PH); canopy diameter North - South (NSD); canopy diameter East-West (EWD); canopy lateral surface (CLS), stem perimeter (SP), and stem cross section (SCS). First year results showed that there was no significant differences in the variables evaluated at P > 0.05, this is probably due to tree size at the moment of the begining of the experiment. That is, they were in average of PH = 4 to 5 m.; NSD = 5 to 5.4 m. and EWD = 4 to 5 m. Similar works from the literature showed that there was not PBZ influences on mango tree sizes during the first year after treatment, but it does in the following year.