Differentiated dynamics of bud dormancy and growth in temperate fruit trees relating to bud phenology adaptation, the case of apple and almond trees.
Few studies have focused on the characterization of bud dormancy and growth dynamics for temperate fruit species in temperate and mild cropping areas, although this is an appropriate framework to anticipate phenology adaptation facing future warming contexts which would potentially combine chill declines and heat increases. To examine this issue, two experimental approaches and field observations were used for high- and low-chill apple cultivars in temperate climate of southern France and in mild climates of northern Morocco and southern Brazil. Low-chill almond cultivars offered an additional relevant plant material for comparison with apple in northern Morocco. Divergent patterns of dormancy and growth dynamics were clearly found in apple tree between southern France and southern Brazil. Divergences were less pronounced between France and Morocco. A global view outlined main differences in the dormancy chronology and intensity, the transition between endordormancy and ecodormancy and the duration of ecodormancy. A key role of bud rehydration in the transition period was shown. High-chill cultivars would be submitted in mild conditions to heterogeneous rehydration capacities linked to insufficient chill fulfillment and excessive forcing linked to high temperatures. This would favor bud competitions and consequently excessive flowering durations and weak flowering. Low chilling requirements in apple and almond would conversely confer biological capacities to tolerate superficial dormancy and abrupt transition from endordormancy to ecodormancy without important heterogeneous rehydration states within buds. It may also assume that low-chill cultivars can also tolerate high temperatures during ecodormancy as well as extended flowering durations.
Faculty of Science, Department of Biology, Moulay Ismaïl University, BP 11 201 Zitoune, Meknès, 50000, Morocco. ad.elyaacoubi@gmail.com.
Adnane
A
El Yaacoubi
Universidade Federal de Pelotas, 96001-970, Pelotas, RS, Brazil.
Gustavo
G
Malagi
INRA, Plant Breeding and Genetic Resources, Regional Agricultural Research, Center of Meknès, Box 578, Meknès, Morocco.
Ahmed
A
Oukabli
Universidade Tecnologica Federal de Parana, 85503-390, Pato Branco, PR, Brazil.
Idemir
I
Citadin
Faculty of Science, Department of Biology, Moulay Ismaïl University, BP 11 201 Zitoune, Meknès, 50000, Morocco.
Majida
M
Hafidi
INRA et Université Blaise Pascal, Unité Mixte de Recherche 547, PIAF, 63100, Clermont-Ferrand, France.
Marc
M
Bonhomme
INRA, Unité Mixte de Recherche 1334, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, 34398, Montpellier, France.
Jean-Michel
JM
Legave
D035264:Flowers / Q000254:growth & development*; D027845:Malus / Q000254:growth & development*; D000068181:Prunus dulcis / Q000254:growth & development*; D012621:Seasons; D013696:Temperature
Ecodormancy; Endodormancy release; Floral primordia; Forcing test; Global warming; Temperature; Vegetative bud; Water content