Exploring bud dormancy completion with a combined architectural and phenological analysis: the case of the apple tree in contrasting winter temperature conditions

Juliano Dutra Schmitz (1, 2) , Yann Guédon (3, 1) , Flavio Gilberto Herter (2) , Gabriel Berenhauser Leite (4) , Pierre-Eric Lauri (1, 5)

1 UMR AGAP - Amélioration génétique et adaptation des plantes méditerranéennes et tropicales
2 UFPel - Universidade Federal de Pelotas = Federal University of Pelotas
3 VIRTUAL PLANTS - Modeling plant morphogenesis at different scales, from genes to phenotype
4 EPAGRI - Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina
5 AFEF - Architecture et Fonctionnement des Espèces Fruitières [AGAP]

• Premise of the study: The branching pattern and phenology of trees result from interactions between the tree’s genetic constitution and environmental conditions. Temperature strongly affects the duration of bud dormancy and further shoot growth. Our hypothesis was that shoot architecture is strongly affected by winter temperatures determining both the position and budburst of vegetative laterals with a lower effect on their outgrowth. • Methods: The study was conducted on four apple cultivars characterized by various chilling requirements and grown in two contrasting winter temperature conditions. A two-step approach was designed to quantify at the shoot scale first the branching pattern and second two phenological stages of vegetative laterals, budburst and outgrowth. A categorical variable, the branching zone, was built to summarize the lateral position along the shoot. It was integrated into the phenological analysis as a factor together with the cultivar and the winter temperature. • Key results: Temperature had a main effect on the distribution of vegetative laterals along the shoot. It also strongly affected budburst, which was also affected by the cultivar and the branching zone. The outgrowth of the lateral was not significantly affected by temperature but was significantly affected by the cultivar and the branching zone. Furthermore, the delayed senescence and subsequent leaf persistence during winter, characterizing the apple tree in the mild winter temperature condition, had only a weak effect on the distribution of vegetative laterals and on budburst and lateral outgrowth. • Conclusions: The actual shoot architecture and budburst result from an ordered sequence of events with a pivotal role of winter temperatures on the dormancy completion of individual lateral buds. Endogenous factors related to the cultivar branching pattern overtake the temperature effect on the lateral outgrowth.

Mots clés: phenology; multiple change-point model; hidden semi-Markov chain; dormancy; vegetative proleptic lateral; budburst; branching dynamics; Malus domestica; winter temperature.

Domaines: Biologie végétale; Applications [stat.AP]

Juliano Dutra Schmitz, Yann Guédon, Flavio Gilberto Herter, Gabriel Berenhauser Leite, Pierre-Eric Lauri. Exploring bud dormancy completion with a combined architectural and phenological analysis: the case of the apple tree in contrasting winter temperature conditions. American Journal of Botany, 2014, 101 (3), pp.398 - 407. ⟨10.3732/ajb.1300335⟩. ⟨hal-01089580⟩