Olive fruit pulp and pit growth under differing nutrient supply

The objetive of this work was to study if the addition of nutrients to the irrigation water modified 'Manzanilla de Sevilla' olive pulp and pit growth. The experiment was carried out during the 2003 fruit-growth period in an irrigated orchard near Seville, southern Spain. Fruit samples were taken in July and September, at 12 and 21 weeks after full bloom (AFB) respectively, in trees irrigated with (T1) or without (TO) the addition of nutrients (N-P-K). The nutrient availability of T1 fruits increased the fruit fresh and dry weight, longitudinal and equatorial diameters, and the pulp-to-pit ratio, characteristics particularly appreciated for table olives. The balance of growth between the fruit mesocarp (pulp) and endocarp (pit) was modified because those two tissues were affected differently. Mesocarp fresh weight was significantly higher at both 12 and 21 weeks AFB in the fertilized treatment, as was mesocarp dry weight at 12 weeks AFB. Neither the endocarp fresh and dry weight nor shape (the ratio of the equatorial and longitudinal diameters) was altered at either of the two studied dates. These results emphasize the importance of an appropriate fertilization management in irrigated olive orchards, particularly for table olives, and also confirm the olive endocarp as a strong sink tissue that competes with the mesocarp, during early development. (C) 2008 Elsevier B.V. All rights reserved.