Evaluation of paclobutrazol on growth, flowering and yield of mango cv. Kensington Pride.
Winston E. C.
Author Affiliation: Queensland Department of Primary Industries, Walkamin Research Station, Walkamin, Qld 4872, Australia.
Australian Journal of Experimental Agriculture 32 : 97-104
Abstract : Paclobutrazol (as a 25% soluble concentrate formulation) was applied at various rates after harvest as a foliar spray, a band along the drip line, or a collar drench, in trials over 3 years on 3-, 4- and 5-year-old trees of cv. Kensington Pride. The trees were assessed for % branches with vegetative flush, flush length, flowering and yield. Paclobutrazol reduced the length of vegetative growth in all trials. Eight ml/tree, applied as a single yearly collar drench, significantly reduced % flush. Collar treatments were significantly more effective than drip line soil-drench treatment in reducing length of vegetative growth. Two years' collar drenches in consecutive years were generally more effective than a band treatment followed by a collar drench. In particular, collar drenches of 4 and 8 ml/tree, applied for 2 consecutive years, reduced summer growth. Flowering and cropping were significantly increased by paclobutrazol in a year of inadequate winter stress, while a trend towards increased yield was noted under more normal conditions. Yield increases were due to improved fruit numbers rather than size. Fruit colour was unaffected. Soil-applied treatments had more effect on flowering and cropping than foliar treatment, with collar drenches being more effective than drip line treatment. A trend for decreasing yields was found when paclobutrazol was applied as a collar drench for 2 consecutive years at the same rate, compared with an ineffective drip line followed by a single collar treatment. Rates of paclobutrazol >4 ml/tree caused unacceptable compaction of flower panicles. Four ml/tree appeared to be the best application rate given the prevailing soil type, climatic conditions, and tree size and age.