GA 4+7 plus BA enhances postproduction quality in pot tulips

Abstract

Previously we reported that postproduction quality of pot ‘Seadov’ tulip ( Tulipa gesneriana) was significantly increased by GA 4+7 plus BA in a manner dependent on the concentration and stage of flower development at application. In these experiments, we extended the survey to 20 tulip cultivars to further evaluate the effects of GA 4+7 plus BA sprays for enhancing postproduction flower and leaf quality. The senescence symptom of the cultivars fell into three categories: wilting, wilting-abscission (abscission shortly after tepal wilting) and abscission (abscission without wilting), with the majority of the cultivars belonging to the wilting and wilting-abscission categories. Pots bearing six plants were sprayed with a range of GA 4+7 plus BA concentrations at marketable stage and placed in a simulated consumer environment (SCE). GA 4+7 plus BA significantly enhanced individual flower and postproduction longevity, but the effect was dependent upon the senescence category of the cultivar. In general, GA 4+7 plus BA increased individual flower and postproduction longevity of wilting-type cultivars at concentrations above 10 mg L −1, while longevity of wilting-abscission-type cultivars was only enhanced by 50 mg L −1. Abscission-type cultivars were not affected by any concentrations of GA 4+7 plus BA. Regardless of floral senescence category, leaf yellowing was significantly reduced by GA 4+7 plus BA sprays in those cultivars showing postproduction leaf yellowing. GA 4+7 plus BA did not induce leaf and stem elongation in most cultivars. Only ‘Yellow Baby’, the shortest cultivar, showed elongation of stem and leaf by GA 4+7 plus BA at concentrations above 25 mg L −1. Spray applications of GA 4+7 plus BA can be useful to enhance flower and leaf quality in pot tulips.