Effect of paclobutrazol on vegetative growth in citrus nursery trees

Abstract

Two foliar sprays of paclobutrazol applied at four different concentrations, viz. 50,100, 200 and 500 mg a.i. l⁻¹ on Citrus volkameriana (Ten. & Parq.) under greenhouse conditions, showed that concentrations of 100 mg l⁻¹and above are suitable for reducing undesirable spindly growth of citrus rootstocks under crowded nursery conditions. Paclobutrazol at 200 and 500 mg l⁻¹ resulted in the greatest growth check and there was no significant difference between these two treatments. At these higher concentrations, however, there seemed to be a residual effect on the subsequent growth of the scions. The growth check on the rootstock at 100 mg l⁻¹ was significantly less than 200 and 500 mg l⁻¹ but still of practical benefit to nurserymen, besides having no residual effect on the growing scions. The treatments did not cause any significant differences in stem diameter and bud take.