ISHS Acta Horticulturae 658: I International Symposium on Rootstocks for Deciduous Fruit Tree Species
COMPARING ROOT AND AERIAL GROWTH DYNAMICS OF TWO APPLE HYBRIDS OWNROOTED AND GRAFTED ON M.9 |
| Authors: | E. García-Villanueva, E. Costes, C. Jourdan |
| Keywords: | Malus x domestica Borkh, growth rhythm, rootstock, rhizotron, root system, digitising |
| Abstract:
The main objective of this paper was to study the growth dynamics of both the aerial and the root systems of two apple genotypes and their possible synchrony or asynchrony within an annual growth cycle. Two different genotypes, corresponding to newly released hybrids from INRA (France) breeding programme were studied. Trees ownrooted and grafted on M.9 were compared. Eight rhizotrons were built at the foot of the same number of trees for root system 2D observations. Roots were drawn every fortnight throughout the growing season and then digitised. As regards the aerial parts, annual shoots of the trunks and long laterals were labelled monthly. As expected, M.9 developed fewer roots than ownrooted trees of both genotypes. Rhythmic root growth was observed in all trees. The roots observed were always fine absorbing roots with a lifespan of about two weeks. However, roots of M.9 had a shorter lifespan than those of the two other genotypes. Regarding the root spatial distribution, the higher the number of roots the deeper their distribution. When ownrooted, X6407 trees produced more roots than X3305 and consequently, X6407 roots were also deeper. Three main periods of root production were observed: June, July and October, specially marked in ownrooted trees. The period of maximal root production, which was July in both ownrooted and grafted trees, followed the second growth unit development on the aerial part of the trees, with one month of delay. | |
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