Influence of the Plant Training System on Yield and Nut Traits of European Hazelnut (Corylus avellana L.) Cultivar Nocchione
Author(s)
Date Issued
2025
Type
article
Volume
15
Issue
2
Start Page
345
Journal
Abstract
The European hazelnut is a temperate nut crop, often managed as a multistemmed
shrub due to its natural aptitude to produce several suckers at the base of the
stump, depending on variety. Traditional hazelnut-growing regions such as Italy, Turkey,
and Spain typically adopt this architecture, while other hazelnut-producing countries such
as the USA, France, and Chile increasingly use single-trunk systems to facilitate orchard
management. Multi-stemmed plants allow gradual renewal through sucker selection but
may lead to excessively dense canopies, reducing the effectiveness of pest and disease
control, increasing biennial bearing, and lowering nut yields in vigorous cultivars. In order
to drive the ongoing enlargement of hazelnut cultivation, attempts in designing highdensity
(HD), and more occasionally super-high-density (SHD), hazelnut orchards are ongoing,
although these are poorly explored in terms of suitable plant training systems, such
that, sometimes, multi-stemmed plant shapes are used; otherwise, single-trunk solutions
are adopted. In order to explore new hazelnut planting and training solutions focused on
sustainable intensification, a trial was established in 2019 in central Italy to evaluate the
eligibility of three training systems (treatment A: regular four-stemmed shrub; treatment B:
single-trunk sapling; treatment C: traditional multi-stemmed shrub), applied on unpruned
three-year-old plants of the hazelnut cultivar Nocchione, planted in the HD approach
(740 plant ha−1). Over five growing seasons (2019–2023), measurements included pruned
wood removed, yield, vigor, yield efficiency, nut and kernel traits, and incidence of the main
commercial defects. In general, treatment A outperformed other plant-shaping systems,
maintaining high yield levels particularly in the two last growing seasons, and showing
a mean kernel/nut ratio of 37.7 and a low incidence of defects. Treatment B achieved the
highest yield efficiency in 2023 but had lower overall yields. Treatment A demonstrated the
most balanced performance, combining high nut quality and stable production, making it
the most promising plant training system for HD hazelnut orchards with planting densities
above 700 plants per hectare. Future research will assess the long-term adaptability of this
plant training system under varying environmental and management conditions