Spray application factors and plant growth regulator performance: IV. Doseresponse relationships

Effect of carrier volume (range 119 to 668 L.ha(-1)) on dose response relat ionships of daminozide and GA(3) was investigated using bean (Phaseolus vul garis L.) seedlings as a model system. Carrier volume was varied by alterin g nozzle travel speed thereby maintaining constant flow rate and droplet si ze. Response was indexed by inhibition (daminozide) or stimulation (GA(3)) of elongation of first plus second internodes above primary leaves 14 days after spray application. Increasing dose by increasing concentration and/or increasing carrier volume at constant concentration increased response. Fo r a given dose retained, response to daminozide was related positively to c arrier volume, while GA(3) response was not affected. Chemical names used: butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); gibberellic acid (GA(3)).