Initial growth and fruiting of ‘Summit’ sweet cherry (Prunus avium) on five rootstocks

Abstract

The sweet cherry (Prunus avium) cultivar ‘Summit’ still fits the standard of excellence for its typical characteristics, including large fruit size and cordate shape. This study was undertaken in Vila Real, northern Portugal, with ‘Summit’ scions raised in a nursery on five rootstocks. The orchard trials were set up in 1999, and tree growth, yield, and fruit size were monitored up to the 6th leaf. At this phase, the rootstock trunk cross‐sectional areas (TCSAs) for Maxma 14, Cab 11E, Edabriz, and Gisela 5 were 79.7%, 60.2%, 37.9%, and 29.3% of that of Mazzard, respectively. Cumulative yield was higher on Gisela 5, but it did not differ significantly from Cab 11E Maxma 14, Edabriz, and P. avium attained only 56%, 50%, and 36% of Gisela 5 cumulative yield per tree, respectively. This latter rootstock also induced higher cumulative yield efficiency when compared with the other rootstocks. Average fruit weight varied significantly according to year, rootstock, and year × rootstock interaction, which accounted for 62.6%, 13.2%, and 19.1% of the total variation, respectively. In 2002, it was Gisela 5 that permitted the cultivar to bear the best‐sized fruits (9.8g), but in 2003 (6th leaf) this rootstock produced the lowest sized fruits(10.2g). Conversely, on Edabriz, Cab 11E, and P. avium average fruit weight increased 29%, 26%, and 24%, respectively. Trees on Gisela 5 had 5.6 leaves (190 cm2) per fruit, whereas on Edabriz, Cab 11E, and P. avium they had 1.6, 2.3, and 6.4 times that value, respectively. Gisela 5 and Edabriz were very efficient in controlling vigour, having induced precocity and high cumulative yield efficiency. Leaf area/fruit ratio, however, limited fruit growth on Gisela 5, where initial high productivities demand appropriate tree nutrition to allow complete fruit, leaf, and limb growth and development on the current and subsequent season. Cab 11E was not so precocious, but proved to be productive and induced the best fruit growth. Suitable cultural practices must be adopted to fit rootstock requirements to optimise the balance between yield, fruit size, and economic value, especially for the most dwarfing.