MANIPULATION OF CROP LOAD IN APPLE (Malus × domestica Borkh.) UNDER HIGH DENSITY PLANTATION
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Date
2021-09
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UHF,NAUNI
Abstract
ABSTRACT
The present investigation entitled “Manipulation of crop load in apple (Malus × domestica Borkh.)
under high density plantation” was carried out in high density apple orchard of Department of Fruit Science, Dr
Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan (HP) during the year 2020-21, in order to
find out the optimum level of crop load for quality fruit production under high density plantation through
chemical and manual thinning. The experiment consist of ten thinning treatments (T1 – NAA @ 10 ppm; T2-
NAA @ 20 ppm; T3- BA @ 100 ppm; T4- BA @ 200 ppm; T5-Metamitron @ 100 ppm; T6-Metamitron @ 200
ppm; T7- Crop load of 4 fruits/cm2 TCSA; T8- Crop load of 6 fruits/cm2 TCSA; T9- Crop load of 8 fruits/cm2
TCSA and T10- Control) and three cultivar treatments (C1 – Jeromine; C2- Redlum Gala and C3- Super Chief)
replicated thrice and was laid out in Randomized Block Design (factorial). Both chemical and manual thinning
was applied at 10 days after petal fall (fruitlets with 10-12 mm diameter). The result obtained from the
experiment depicted that the highest yield (12.69 kg/tree) was recorded in crop load of 8 fruits/cm2 TCSA.
However, the crop load of 4 fruits/cm2 TCSA resulted in best quality fruits in terms of maximum fruit length (
62.03 mm), diameter (71.28 mm), weight (154.48 g), volume (180.28 cc), firmness (9.04 kg/cm2), red skin
colour (96.67%), TSS (14.51 °B), total sugars (13.86%), reducing sugars (9.57%), non-reducing sugars (4.07%),
anthocyanin content (0.62 OD), return bloom (43.64) and minimum titratable acidity (0.19%), followed by crop
load of 6 fruits/cm2 TCSA through manual thinning and NAA @ 20 ppm in case of chemical thinning in
comparison to control (no thinning). With respect to cultivars, highest extent of thinning (45.82%), return bloom
(36.67), TSS (12.99 °B), total sugars (11.80%) and reducing sugars (8.39%) was recorded in Redlum Gala.
Whereas, the Jeromine cultivars recorded maximum fruit length (60.46 mm), diameter (68.94 mm), weight
(135.09 g), volume (170.16 cc), red skin colour (95.10%) and anthocyanin content (0.62 OD). The treatment
combination T7C1(Crop load of 4 fruits/cm2 + Jeromine) recorded highest fruit length (65.26 mm), diameter
(73.89 mm), weight (157.53 g), volume (184.43 cc), whereas, the highest TSS (15.36 °B), total sugars (14.22%),
reducing sugars (10.21%) was recorded in T7C2 (Crop load of 4 fruits/cm2 + Redllum Gala) in comparison to all
other treatment combinations. Hence, the optimum level of crop load for quality fruit production in apple under
high density plantation ranged from 4-6 fruits/cm2 TCSA.