CONTRIBUTIONS TO THE EFFICACY OF BENZYLADENINE AS A FRUIT THINNING AGENT FOR APPLE CULTIVARS

Paturyl 10 WSC with a.i. benzyladenine (BA, 10 %) was applied for fruit thinning in trees of cultivars belonging to the group of Golden Delicious-like and spur-type Delicious varieties.
This product has primarily been introduced and registered as a feathering agent to treat trees of young orchards, or whips in nurseries.

Trees of cvs. ‘Golden Li 85–50’ and ‘Wellspur Delicious’ were treated at a BA rate of 50 or 100 ppm (1995) and 40, 80 or 120 ppm (1996,1997). Timing of treatments were based upon the diameter of fruitlets (11 to 12 mm in 1995, 9.1 to 9.7 mm in 1996 and 11 to 12 mm in 1997).

Treatments of 40 and 50 ppm, resp., proved to be reliable for thinnig fruitlets in 1995 and 1996. Final fruit set on spurs of cv. ‘Golden Li 85–50’ was 30 to 32 fruits/100 inflorescens but 53 to 55 in untreated trees, similar data recorded in trees of ‘Wellspur Delicious’ were 33 to 46 and 58 to 59, respectively.
This resulted a reduction of yield, however, the size of fruits as well as return bloom were enhanced.
Trees of cv ‘Wellspur Delicious’ were considerable less responsive to the BA treatments than those of cv ‘Golden Li 85–50’.

Treatment effects proved to be dependent of temperature, especially in a period of 10 days after spraying.
The unfavourable effect of a rainfall within 24 hours following treatments may be prevented better by using a light summer oil as surfactant than by the conventional Tween-20.

XXV International Horticultural Congress, Part 4: Culture Techniques with Special Emphasis on Environmental Implications

T. Bubán, T. Lakatos

Apple, benzyladenine (BA), biennially bearing, feathering agent, fruit thinning

https://doi.org/10.17660/ActaHortic.2000.514.6