ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
CAN FRUIT SIZE AND COLOURING OF 'JONAGOLD' BE IMPROVED BY A DIFFERENT ROOTSTOCK? |
| Authors: | J. Vercammen, G. van Daele, A. Gomand |
| Keywords: | M.9-selections, M.9 F.l56, J.TE.G, P16 and P22 |
| Abstract:
In the fruit sector, everybody, from the fruit grower to the researcher, is searching for a tree that can be easily controlled, that does not grow too strongly and that gives good production of high quality fruit each year. That is why years ago, they started using rootstocks. Although in most cases M.9 is a satisfactory rootstock, some conditions demand less vigorous trees. Moreover, the colouring is not always as good as it should be and recently, we have observed that ‘Jonagold’ is often too large when grown on M.9. In many cases, we need a tree with vigour o between that of M.9 and M.27. One way to achieve this is the use of another rootstock. Up until now, we have not found a better rootstock than M.9 in our rootstock experiments. Nevertheless, there are two rootstocks for ‘Jonagold’, J.TE.G. and P16, show promise. J.TE.G. is 15% less vigorous than M.9. The production efficiency and colouring remain the same, but there are more kilos of A2++ in the 70-85 mm size class because of its smaller fruit size. P16 is 30% less vigorous. The colouring and the production are comparable to those of M.9 and over the years, the fruit size remains somewhat smaller on average. The combination of less vigour and similar yield increases the production efficiency of P16 compared with M.9-29. Where the vigour of M.9 is too strong, selections of M.9 with less vigour can be used. The most suitable selection for this purpose is M.9 F.l56. This selection has the weakest growth and the fruit size can be compared to that of M.9-29. With respect to colouring, there is no improvement. However, further research is still necessary. | |
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