Articles
FRUIT SET AND RETURN BLOOM OF LIGHT, MEDIUM AND HIGH FLOWERING APPLE TREES AFTER BA APPLICATIONS
Article number
884_41
Pages
351 – 356
Language
English
Abstract
Selected light (L), medium (M) or high (H) flower setting apple trees were sprayed with 6-benzyladenine (BA) 100 mg/L to Golden Delicious/M.9, and BA 150 mg/L to Elstar/M.9 trees at 6 mm, 10 or 15 mm king fruit diameter (KFD). BA applications significantly reduced the Golden Delicious final fruit set if applied on L trees at 15 mm KFD, on M trees at 6 mm KFD and on H trees at 6, 10 or 15 mm KFD. On Elstar, BA applications induced stronger fruit shedding in all three initial flowering groups: L trees at 6 and 10 mm KFD, but M and H trees at 6, 10 and 15 mm KFD applications.
Flower intensity in the year of cropping had stronger influence on return bloom than reduced final fruit set induced by BA. On both cultivars much better return bloom was observed on L trees than on M trees, and the smallest return bloom was expressed on H trees.
The application of BA did not enhance return bloom on L trees.
When BA was applied on M and H trees and consequently induced thinning, significant increased return bloom was observed on thinned trees, but not to the level of flowering on L trees.
Separate experiment was conducted with the aim of enhancing return bloom where five successive weekly applications of naphthalenecetic acid (NAA) 5 mg/L or ethephon 100 mg/L were sprayed, starting 3 weeks after petal fall on L, M and H Golden Delicious/M.9 trees previously thinned with BA 100 mg/L. BA induced insignificant thinning on L trees, but it was significant on M and H trees.
Five successive applications of NAA or ethephon did not induce additional thinning on BA thinned trees.
Five NAA sprayings provoked additional return bloom on H trees independent on the usual effect of enhanced return bloom induced by thinning on these trees.
Flower intensity in the year of cropping had stronger influence on return bloom than reduced final fruit set induced by BA. On both cultivars much better return bloom was observed on L trees than on M trees, and the smallest return bloom was expressed on H trees.
The application of BA did not enhance return bloom on L trees.
When BA was applied on M and H trees and consequently induced thinning, significant increased return bloom was observed on thinned trees, but not to the level of flowering on L trees.
Separate experiment was conducted with the aim of enhancing return bloom where five successive weekly applications of naphthalenecetic acid (NAA) 5 mg/L or ethephon 100 mg/L were sprayed, starting 3 weeks after petal fall on L, M and H Golden Delicious/M.9 trees previously thinned with BA 100 mg/L. BA induced insignificant thinning on L trees, but it was significant on M and H trees.
Five successive applications of NAA or ethephon did not induce additional thinning on BA thinned trees.
Five NAA sprayings provoked additional return bloom on H trees independent on the usual effect of enhanced return bloom induced by thinning on these trees.
Authors
M. Stopar
Keywords
Malus × domestica, thinning, 6-benzyladenine, flower formation, naphthalenecetic acid
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