FLOWERING RESPONSE OF BOUGAINVILLEA CULTIVARS TO DIKEGULAC

Foliar spray application of dikegulac at 1600 mg-liter-1 during produc tion of Bougainvillea glabra Choicy 'Mauna Kea White', and Bougainvill ea 'Raspberry Ice', 'Royal Purple', 'Summer Snow', and 'Temple Fire' i n 4.5-liter hanging baskets (25.4 cm in diameter) was investigated in relation to flowering. The effect of foliar-applied dikegulac at 0, 40 0, 800, 1200, and 1600 mg-liter-1 on bracteole size of 'Mauna Kea Whit e' was also determined. Liners of 'Temple Fire' pruned at transplantin g (0 weeks) and sprayed with dikegulac at 0 and 4 weeks had increased flowering and a slightly more compact, pendulous growth habit than pla nts that had only been pruned at 0 and 4 weeks. Dikegulac had little t o no effect on flowering of the other cultivars. Under late-spring to early summer conditions (generally increasing temperatures), bracteole size of 'Mauna Kea White' was reduced almost-equal-to 25% by 400 mg d ikegulac/liter compared to nontreated plants; 800 to 1600 mg dikegulac /liter reduced bracteole size almost-equal-to 37%. Under late-summer t o mid-fall conditions when the weather was cooler and wetter, dikegula c had little to no effect on bracteole size; however, bracteoles of no ntreated plants were almost-equal-to 25% smaller than those of plants grown under the warmer and drier conditions of late spring to early su mmer. Chemical name used: sodium salt of methylethylidene)-alpha-L-xyl o-2-hexulofuranosonic acid (dikegulac).