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Relation between Early Drop of Apple Fruit and Endogenous Growth Regulators, and Effects of MCPB, GA3 plus GA4 and BA Sprays on Fruit Abscission

Year: 1989
Type: article
Abstract: The relationship between the early drop of apple fruit, and auxin, gibberellin and cytokinin-like substances in the seeds was investigated from 16 days after full bloom (AFB) by comparing ‘Starking Delicious’ and ‘Fuji’ apple fruits. In addition, the effects of a spray of 2-methyl-4-chlorophenoxy butyric acid ethyl solution (MCPB, 10ppm), a solution containing gibberellin A3 and gibberellin A4 at 50ppm each (GA3+GA4), and a 6-benzylamino purine solution (BA, 100ppm) were investigated under shading treatment which promoted fruit abscission.1. In both cultivars, auxin-like activity in the seeds hardly differed from 16 days to 60 days AFB. However, MCPB spray slightly reduced fruit abscission, although most fruits were small since seed abortion had been increased by the shading treatment.2. The level of gibberellin-like substances in the seeds of ‘Fuji’ increased on and after 23 days AFB, whereas that of ‘Starking Delicious’ increased on and after 42 days AFB when early fruit drop ceased. Moreover, the GA3+GA4 spray satisfactorily reduced fruit abscission and promoted fruit growth regardless of seed abortion by the shading treatment. Therefore, it is considered that gibberellins in the seeds are closely associated with early fruit drop and fruit growth.3. The peak level of cytokinin-like substances of ‘Fuji’ at 25 days AFB was 6 days earlier than that of ‘Starking Delicious’. Hence, BA was sprayed on the 19th day AFB when the level of cytokinin-like substances of ‘Starking Delicious’ was low, although, it increased fruit abscission. This may have been influenced by ethylene evolution from the fruit which increased after the BA spray.
DOI: 10.2503/jjshs.58.9
Language: English
Subfield: Plant Science
Open Access status: diamond
OpenAlex ID: W1978744372
FWCI: 0.506
Cites: 30
Cited by: 10
Related to: 10