Effects of the bioregulators ACC, 6-BA, ABA, and NAA as thinning agents on Gala apples

Abstract

Gala apple (Malus domestica Borkh.) trees are prone to heavy cropping but respond to chemical fruitlet thinners to reduce crop load and improve fruit quality. Environmental concerns over the fate of the chemical fruitlet thinner carbaryl is widely acknowledged, but crop load management options are limited. In southern Ontario, Gala trees were treated with new thinning compounds or combinations to determine post-bloom thinning efficacy and resulting fruit quality. Treatments included 6-benzyladenine (6-BA) combined with naphthaleneacetic acid (NAA) or abscisic acid (ABA), and 1-aminocyclopropane-1-carboxylic acid (ACC) alone applied at 9 mm in 2014 and 17 mm in 2015. The treatment NAA + 6-BA produced unacceptably small “pygmy” fruit when applied at 17 mm fruitlet diameter. ABA at 150 and 300 mg L−1 and ACC at 150 mg L−1, when applied at 17 mm fruitlet diameter, resulted in acceptable fruit set, crop load, and quality results in comparison with the carbaryl thinner in 1 yr. The bioregulators ACC and ABA combined with 6-BA showed commercial potential for thinning Gala fruit but require further evaluation.

Effect of thinning with metamitron, NAA, BA and naphthenic acids on apple (Malus domestica) trees

“…( Dennis (2003) and Cortens and Cline (2019) shown that fruit thinning improves flower initiation and hence return bloom for the following season. This concurs with our results which showed that the high thinning efficiency can improve the return bloom.…”

An anti-scratch flexible SERS substrate for pesticide residue detection on the surface of fruits and vegetables

“…6-BA is a synthetic cytokine that can keep plants fresh by delaying the degradation and senescence of protein, nucleic acid, and chlorophyll. It can promote seed germination and seedling growth, thus being widely used in agriculture, horticulture, and other fields [38][39][40]. However, 6-BA is harmful to the human body.…”

Bloom and Postbloom Thinner Effects and Interactions on ‘Gala’ Fruit Growth Rate, Return Bloom, and Yield Responses at Three Locations

“…Many of these products do not require supplemental use of carbaryl for sufficient thinning activity. Abscisic acid is mild thinner that is most effective in combination with other products (Cortens and Cline 2019). Metamitron is a photosynthetic inhibitor with thinning activity when applied at $10 to 20 mm (Basak 2011;McArtney and Obermiller 2012).…”