CRESCIMENTO DE MINIRREBOLOS DE CANA-DE-AÇ�CAR SOB DOSES DE ÁCIDO INDOLBUTÀRICO E ÁCIDO GIBERÉLICO

Abstract

THE ADOPTION OF MECHANIZED PLANTING OF SUGARCANE CAUSED AN INCREASE IN THE NUMBER OF FAILURES IN PLANTING, WHICH CAUSED LOSSES IN PRODUCTIVITY. DUE TO THIS, THE CANA PROGRAM OF THE AGRONOMIC INSTITUTE OF CAMPINAS (IAC) DEVELOPED THE SYSTEM OF PRE-BUDDED SEEDLINGS (MPB) WITH THE PURPOSE OF REDUCING THE VOLUME OF SEEDLINGS AND FAULTS, BESIDES ALLOWING GREATER QUALITY CONTROL, BOTH FOR CONTROL OF PESTS AND DISEASES AS WELL AS FOR THE UNIFORMITY OF THE CANE FIELD. HOWEVER, THE DEVELOPMENTAL CAPACITY OF THE GEM AND ROOT SYSTEM OF THE MINI-TREE IS VARIABLE WITH THE VARIETY. THUS, THE USE OF PLANT REGULATORS MAY INDUCE THE DEVELOPMENT OF THE MINI-TREE, SUCH AS GIBBERELLIC ACID, WHICH MAINLY INFLUENCES THE AERIAL PART ELONGATION AND INDOLEBUTYRIC ACID, WHICH IS CONSIDERED ONE OF THE MAJOR ROOTING STIMULATORS. THE OBJECTIVE OF THIS STUDY WAS TO VERIFY THE USE OF INDOLEBUTYRIC ACID AND GIBBERELLIC ACID ASSOCIATED WITH IMMERSION TIMES AS SPROUTING STIMULANT AND ROOTING IN PRE-SPROUT MOLASSES (MPB) OF SUGARCANE. THE EXPERIMENTAL DESIGN WAS COMPLETELY RANDOMIZED, WITH FOUR REPLICATES IN A 5 X 3 FACTORIAL SCHEME (DOSES OF AIB (500, 1000 MG L-1), DOSES OF GA (60 MG L-1) AND ASSOCIATED DOSES OF AIB AND GA + 60 AND 1000 + 60 MG L-1) AND IMMERSION TIMES (60, 120, 180 SECONDS)], IN A TOTAL OF FIFTEEN TREATMENTS + CONTROL - IMMERSED IN DISTILLED WATER. THE PERCENTAGE OF SPROUTING AND DRY MASS OF THE AERIAL PART OF SUGARCANE MINI GRINDSTONE PRESENTED INFERIOR RESULTS WHEN COMPARED TO THE CONTROL. FOR PLANT HEIGHT, SHOOT GREEN MASS, DRY SHOOT MASS AND ROOT DRY MASS, THE DOSE OF 1000 MG L-1 SHOWED BETTER RESULTS IN BOTH. FOR THE PARAMETERS PLANT HEIGHT, SHOOT GREEN MASS, DRY SHOOT MASS AND ROOT DRY MASS, THE DOSE OF 500 MG L-1 WAS STATISTICALLY LOWER THAN THE OTHERS. THE USE OF THE INDOLBUTYRIC ACID AND GIBBERELLIC ACID GROWTH REGULATORS ASSOCIATED WITH THE IMMERSION TIMES DID NOT POSITIVELY INFLUENCE THE GROWTH OF THE SUGARCANE MINI GRINDSTONE IN RELATION TO THE CONTROL.