ISHS Acta Horticulturae 732: VIII International Symposium on Canopy, Rootstocks and Environmental Physiology in Orchard Systems
THE EFFECT OF ROOTSTOCKS ON THE RETENTION OF APPLE QUALITY |
| Author: | J. Skrzyński |
| Keywords: | Malus domestica, flesh firmness, soluble solids, shelf-life, physiological disorders, fruit K/Ca |
| Abstract:
The type of rootstock is one of the orchard factors that could influence the quality of fruits. The effect of rootstocks on quality parameters has not been fully documented so far. Experiments were carried out on fruits from ‘Jonagold’ trees on rootstocks of Polish selection: P2, P14, P22, P60 and the well known Malling Series: M.26 and M.9. The studies were conducted over five consecutive seasons in the period of full production capacity of the experimental orchard (from 4 - 9 years after planting). Fruit were stored in conventional refrigerated rooms at 1-2°C, 90-92% RH for 180 days. Flesh firmness retention, soluble solids and titratable acidity were analyzed after storage and after 7 days at 20°C (simulated marketing period). The incidence of storage diseases and disorders were recorded. Fruit Ca and K content were measured at harvest; and K/Ca ratio was calculated. The results show that rootstocks influence the quality of fruit after storage and after additional periods of simulated shelf life. During those periods, the maintenance of flesh firmness, total soluble solids, acidity and sugar to acid ratio was the best for ‘Jonagold’ apples from trees on P60 and P22. Fruits from those rootstocks may fully satisfy the consumer’s expectations for fresh consumption. The incidences of physiological disorders (predominantly bitter pit) and of storage diseases (rots) are rootstock dependent. Fruits from trees on M.9 and P14 were most often affected by these defects and the percentage of sound fruits was the lowest. The highest percentage of sound fruit during each of the seasons was for apples from trees on P60 rootstock. A moderate K/Ca ratio (within a range of 22-30) in fruits from trees on those rootstock may be a partial explanation of that fact. | |
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