Application of Architectural Analysis and AMAPmod Methodology to Study Dwarfing Phenomenon: the Branch Structure of 'Royal Gala' Apple Grafted on Dwarfing and Non-dwarfing Rootstock/Interstock Combinations

Abstract

Architectural analysis was applied to study branch development of 'Royal Gala' apple trees grafted with dwarfing and non-dwarfing rootstock/interstock combinations, which had been chosen to produce trees with a wide range of vigour. Using AMAPmod methodology, the structure of 3-year-old branches was described at four levels of representation: branch; annual shoot; growth unit; and node. Three types of growth units were distinguished: extension growth unit (vegetative unit with internode extension); vegetative spur with minimal internode extension; and fruiting spur or bourse. The aim of the analysis was to describe exactly how the rootstock/interstock combinations affected the structure building process. The number of extension growth units, vegetative spurs and fruiting spurs per annual shoot changed over the years, but this was not affected by rootstock/interstock combination. Compared with MM.106 rootstock, M.9 rootstock reduced the number of nodes per extension growth unit. In most cases, rootstock/interstock combination had no effect on the linear relationship between extension growth unit length and node number (R(2) = 0.88). Average internode length depended on unit node number, with internodes being shorter for units with fewer nodes. Thus the difference in apple branch size induced by the rootstock/interstock combinations was mainly due to a reduction in the length and number of neoformed nodes produced on extension growth units. As percentage budbreak of axillary buds on extension growth units was not affected by rootstock/interstock combination, differences in numbers of axillary annual shoots per branch were entirely due to differences in the total numbers of nodes extended during the previous year.

Influence of cultivar and rootstock on early growth and syllepsis in nursery trees of pear (Pyrus communis L., Rosaceae)

“…The TD is used to calculate the trunk cross-sectional area (TCSA), both values testifying to the strength of the tree growth. The TCSA in apple 'Royal Gala' is significantly affected by rootstock and/or interstock (Seleznyova et al, 2003), the finding being in conformity with the results of the present study for the second season, though, when the effect of BA 29 on TD was facilitated and that of MA diminished most likely by a factor that was not controlled in the trial.…”

“…Nevertheless, pear is usually considered as a vigorous species and its branching habit is often naturally erect. Dwarfing rootstocks are commonly used to reduce more rapidly the vigour of the pear trees, and consequently to promote earlier flowering (Seleznyova et al, 2003). However, the present study showed that the trees which developed fewer sylleptic shoots in the first years of growth were not the best solution to obtain an entrance into the productive period in the second and third year.…”

Stability of the annual shoot diameter in Persian walnut: a case study of different morphotypes and years

“…Due to a high level of heterozigosity, each tree represented a unique genotype which strongly affects fruiting behaviour of the tree and, consequently, morphometric traits of the shoots. Our results revealed a genetically determined plan of the annual shoots development, which is, according to Seleznyova et al (2003), one of the primary aims of the architectural analysis in general.…”

Apple dwarfing rootstocks exhibit an imbalance in carbohydrate allocation and reduced cell growth and metabolism

“…Despite their utility and a century of research, the underlying mechanism of rootstock-induced dwarfing is still unknown. The effects of dwarfing rootstocks are apparent within the first year after grafting and include reduced root growth, 1–3 a decrease in the length and node number of the primary axis, 4–6 a decrease in the number and length of sylleptic shoots 7,8 and/or an increase in the proportion of floral buds along the primary axis. 8–10 …”