EFFECT OF 6-BA AND NAA AS THINNING AGENTS OF ‘CONFERENCE’ PEAR

Trials on ‘Conference’ pear were carried out over the years 1999 to 2003 to test the thinning efficacy of NAA at 10-20 ppm, 6-BA at 200 ppm and NAA+6-BA as compared to untreated and hand-thinned trees. 6-BA at 200 ppm applied alone or in combination with NAA reduced fruit set to 73 and 64% with regard to untreated trees, respectively. The effects on average fruit weight showed interaction with the year and no statistically significant differences were found on production or return bloom. Although differences were not significant, efficacy of NAA increased with the dosage. NAA applied in 2003 at 20 ppm reduced fruit set to 72.1%. Further trials are needed to discard a negative effect of NAA applied at high dosage on return bloom.