Articles
Reduction of flowering in nectarine ‘Dulciflora 2’ by gibberellic acid applications
Article number
1457_63
Pages
507 – 514
Language
English
Abstract
The main objective of fruit thinning in Prunus persica (L.) Batsch (peach, nectarine, and their variations) is to obtain fruit of commercial size.
Thinning is an operation traditionally performed by hand; however, this procedure is not the most suitable for early ripening cultivars due to their short reproductive cycle.
Additionally, hand fruit thinning is both expensive and labor-intensive.
Chemical thinning has failed to establish itself as a reliable alternative for stone fruit crops, so mechanical thinning is one of the few possibilities available to growers to reduce labor costs.
Unfortunately, the mechanical removal of fruitlets causes damage to the developing fruits and tends to remove the larger ones.
Thus, for early-maturing cultivars, farmers often rely on flower thinning at bloom using portable electronic devices to remove some flower buds and reduce flowering levels mechanically.
In this experiment, we investigated how the application of gibberellic acid (GA3) to nectarine trees (Prunus persica var. nucipersica) cultivar ‘Dulciflora 2’ can further reduce flowering levels.
Treatments applied were 0 (control), 50, 100, 200, and 400 mg L‑1 of GA3. The experiment was repeated on three different dates (June 30, July 16, and July 29, 2021) on different trees to explore the optimal dates for GA3 applications.
The highest rates of GA3 (400 mg L‑1) significantly reduced flower number and, consequently, flower thinning time by up to 66% compared to the control.
Lower effects were obtained with lower doses.
GA3 applications had the greatest effect at the earliest date, but their effectiveness declined later.
Despite success in reducing flowering, GA3 caused a phenological delay at doses of 100 mg L‑1 and higher.
In conclusion, applications of GA3 at 200 and 400 mg L‑1, applied in June, could be an alternative (or complementary) to traditional hand fruit thinning, thereby reducing labor costs in peaches.
Thinning is an operation traditionally performed by hand; however, this procedure is not the most suitable for early ripening cultivars due to their short reproductive cycle.
Additionally, hand fruit thinning is both expensive and labor-intensive.
Chemical thinning has failed to establish itself as a reliable alternative for stone fruit crops, so mechanical thinning is one of the few possibilities available to growers to reduce labor costs.
Unfortunately, the mechanical removal of fruitlets causes damage to the developing fruits and tends to remove the larger ones.
Thus, for early-maturing cultivars, farmers often rely on flower thinning at bloom using portable electronic devices to remove some flower buds and reduce flowering levels mechanically.
In this experiment, we investigated how the application of gibberellic acid (GA3) to nectarine trees (Prunus persica var. nucipersica) cultivar ‘Dulciflora 2’ can further reduce flowering levels.
Treatments applied were 0 (control), 50, 100, 200, and 400 mg L‑1 of GA3. The experiment was repeated on three different dates (June 30, July 16, and July 29, 2021) on different trees to explore the optimal dates for GA3 applications.
The highest rates of GA3 (400 mg L‑1) significantly reduced flower number and, consequently, flower thinning time by up to 66% compared to the control.
Lower effects were obtained with lower doses.
GA3 applications had the greatest effect at the earliest date, but their effectiveness declined later.
Despite success in reducing flowering, GA3 caused a phenological delay at doses of 100 mg L‑1 and higher.
In conclusion, applications of GA3 at 200 and 400 mg L‑1, applied in June, could be an alternative (or complementary) to traditional hand fruit thinning, thereby reducing labor costs in peaches.
Publication
Authors
L. Parra, F.M. Chiamolera, V. Pinillos, J. Cuevas
Keywords
Prunus persica, GA3, flowering inhibition, thinning, flower buds drops, phenology delay
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