Patterns of size and fate relationships of contiguous organs in the apple (Malus domestica) crown

Abstract

Summary• In apple ( Malus domestica ), the size of a shoot and the vegetative or reproductive fate of the terminal bud on that shoot are considered to be related phenomena but with contrasted results depending on studies. Our hypothesis was that these relationships would be partly cultivar-dependent.• Over a 3-yr period, the size relationships between shoots and fruit on two architecturally contrasted apple cultivars were assessed. For shoots, flowering frequency (dependent variable) was related to subtending shoot size (independent variable).• Linear correlations were adjusted for size relationships between contiguous shoots in the same year (inflorescence vs bourse-shoot), and between years with differences in slopes and intercepts between the two cultivars. The relationships between the size of a shoot and flowering frequency differed between the two cultivars, with high flowering whatever shoot size vs parabolic relationships between the two variables, respectively.• It is concluded that the relationships between shoot size and fate are cultivardependent. It is speculated that the flowering pattern not only depends on the property of the shoot alone, but also on the structural proportions of the parent branch and branching density.Key words: allometry, apple ( Malus domestica ), flowering pattern, fruit and shoot size, parent branch, reproductive shoot, return-bloom, vegetative shoot.

Environment and position of first bud to break on apple shoots affects lateral outgrowth

“…It is possible that the length of one annual shoot and that of the succeeding annual shoot is genetically regulated (Lauri and Trottier 2004), and/or related to the ability of the terminal bud to retain its reserves while the laterals readily distribute them to surrounding laterals (Hansen 1969).…”

Fruit Self-Thinning: A Trait to Consider for Genetic Improvement of Apple Tree

“…Spurs mutants with short internodes and lateral branching have an enhanced precocity and a greater fruit-setting ability [23], [24], even though they tend to be alternate bearing [25]. Additional evidence of the impact of vegetative shoot length on terminal bud floral induction and fruit setting has been provided, supporting the assumption of within tree variation of fruit set [5] [26]. Describing the genetic variability of architectural traits among cultivars and progenies, [20] noticed several cultivars and hybrids that exhibited a fruit self-thinning behaviour.…”

Cost and probability of flowering at the shoot level in relation to variability in shoot size within the crown of Vaccinium hirtum (Ericaceae)

“…Overall, the probability of flowering increases with increased shoot size, reaching a maximum at a medium shoot size and declining thereafter. Such a nonlinear trend between floral induction and vegetative shoot vigor has been reported in several temperate trees, including Betula pendula (Maillette, 1982), Alnus hirsuta (Hasegawa & Takeda, 2001), Eurya japonica (Suzuki, 2000), Fraxinus pennsylvanica (Remphrey et al ., 2002), and Malus domestica (Costes et al ., 2003; Lauri & Trottier, 2004).…”