A SINGLE METAMITRON SPRAY THINNED ‘BROOKFIELD GALA’ APPLES AS EFFECTIVELY AS A PROGRAM OF TREATMENTS BASED ON NAA, CARBARYL AND BA

A trial was established to determine the thinning effect of combinations of NAA, applied at flowering, and metamitron (350 mg L^-1), applied at petal fall or/and fruit of 10 mm, in ‘Brookfield Gala’/Pajam2 apple trees; they were also compared with standard treatments for chemical thinning in Chile, based on NAA at bloom, carbaryl at petal fall and carbaryl mixtures with NAA or BA at 10-12 mm fruit.
We used 6 plants per treatment in a completely randomized design.
Fifty days after flowering, fruit set and crop load were evaluated; fruit size and yield were determined at harvest.
In order to evaluate treatment effects on fruit size, analysis of covariance was performed to discount the effect of crop load.
Metamitron applied at petal fall and/or 10-11 mm fruit thinned the trees effectively.
Generally, the effect of metamitron was additional to that caused by NAA. A single application of metamitron was as effective as a program of treatments that includes NAA at bloom, carbaryl at petal fall and NAA or 6-benzyladenine plus carbaryl on 10 mm fruits.
The most effective treatments showed intense and early thinning; when covariance analysis removed the effect of crop load, those treatments showed improved yield and average fruit size.
The crop load reduction caused by metamitron improves fruit growth, but it seems that to a lesser degree than treatments based on growth regulators.

X International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems

G. Reginato, H. Osorio , J. Navarrete

fruit size, crop load, fruit growth stage

https://doi.org/10.17660/ActaHortic.2014.1058.48