Apple tree adaptation to shade in agroforestry: an architectural approach

Abstract

PREMISE The expression of shade adaptation traits is expected to be stronger in low light and can be detrimental to flowering and yield. Our study focused on the expression of shade adaptation traits of apple trees (Malus domestica Borkh. ‘Dalinette’) in an agroforestry system. METHODS The architecture of 45 apple trees in their third and fourth year was extensively described and analyzed at the tree scale and compared depending on the light quantity received during the growing season. Flower cluster phenology and the relation between leaf area and floral initiation were also investigated. RESULTS The number of growing shoots and the leaf area were reduced by shade even if specific leaf area increased with increasing shade. Shade did not modify primary growth but did decrease secondary growth, so that apple tree shoots in shade were slender, with a lower taper and reduced number and proportion of flower clusters. The correlation between floral initiation and leaf area was high both in full and moderate light but not for apple trees in low light. Shade did not impact the date of bud burst and the early phenological stages of flower clusters, but it reduced the number of days at full bloom. CONCLUSIONS Our results suggest that while the architecture of apple trees is modified by a reduction in light intensity, it is not until a reduction of 65% that the capability to produce fruit is impeded. These results could help optimize the design of apple‐tree‐based agroforestry systems.

Functional trait divergence associated with heteromorphic leaves in a climbing fig

“…In conditions of low light intensity, plants tend to dedicate more resources towards enlarging the surface area of their leaves and enhancing their capacity to capture light. Therefore, SLA of plants at low light conditions is generally high ( Sevillano et al., 2016 ; Pitchers et al., 2021 ; Tang et al., 2022 ). For example, Paź-Dyderska et al.…”

“…In conditions of low light intensity, plants tend to dedicate more resources towards enlarging the surface area of their leaves and enhancing their capacity to capture light. Therefore, SLA of plants at low light conditions is generally high (Sevillano et al, 2016;Pitchers et al, 2021;Tang et al, 2022). For example, Paz-Dyderska et al ( 2020) measured the SLA of the sunny and shaded leaves of 179 woody plants, except for a very few species, the SLA of the shade leaves in most plants is greater than that of full-light leaves.…”

Daño de sol y potencial hídrico de tallo y tejidos del fruto de manzanas (Malus domestica) ‘Brasil Gala’, ‘Cripps Pink’ y ‘Granny Smith’

“…Boini and others (18) , in line with Severino and others (2) , conclude that sun damage is more related to water status than to radiation. On the other hand, the use of nets, whether aiming to reduce sun damage, hail damage or for phytosanitary protection, presents adverse effects on color picking in two-tone cultivars (7) and, depending on the level of shading, it could affect floral induction and the vegetative/reproductive ratio (21) .…”