Influence of planting density, canopy architecture and drip fertigation on plant growth and productivity of apple (Malus × Domestica borkh.)

The experiment laid out in a randomized block design (factorial) had treatment combinations of three planting density, two training systems and fertigation doses of 100 and 75 per cent of AD (NPK). The results revealed that trees planted at a density of 2666 trees ha⁻¹ registered highest annual shoot growth, increase in tree height, spread, scion girth, and volume. The lowest tree growth was recorded in high density planting of 5333 trees ha⁻¹. The results showed a positive relationship between productivity and planting density. The productivity increased with increasing density, while yield per trees decreased. Among the training systems, vertical axis trained trees reported the highest annual shoot growth, increase in tree height, spread, scion girth, and volume and the lowest tree growth was observed in vertical axis system. However, the maximum productivity was registered by the trees trained with Tall spindle system and the minimum was noted in vertical axis system. In case of fertigation, significantly highest tree growth parameters and productivity was registered by the trees subjected 100% AD (NPK). Among three factors interaction, the highest tree growth parameters were recorded in trees planted at density of 2666 trees ha⁻¹, trained with vertical axis and subjected 100% AD (NPK).