EFFECT OF FRUIT NUMBER PER CLUSTER AND HARVEST DATE ON THE QUALITY OF ‘RAYADA’ APPLE

Abstract

Apple (Malus domestica Borkh) produced under dry land conditions in the Mountains of Querétaro, México, is traded at low prices due to its low quality and because its fruits ripen when the national market is saturated. However, in the region there is one promising early ripening variety locally called ‘Rayada’ whose small fruits are due to the abundant set in the clusters. In this research we evaluated the effect of the number of fruits per cluster and the harvest date on: fruit weight, diameter, total soluble solids (TSS), total titratable acidity (TTA), firmness and calcium concentration, in the ‘Rayada’ apple produced in the Mountains of Querétaro, A factorial experiment in a randomized complete blocks design was established, using 10 selected mature trees grafted on MM 111, based in their yield. Theses trees naturally set 1, 2, 3 or 4 fruits per cluster, were sampled during seven harvest dates, on a weekly interval starting June 29th. With one fruit per cluster, the highest fruit weight (102.6 g), equatorial diameter (64.0 mm) and calcium concentration (10.45 mg 100 g^-1 PF) were obtained. The best harvest date for ‘Rayada’ apple in the Mountains of Querétaro was from late July to early August where fruits attained maximum weight and diameter (101.6 g, 64.4 mm) and the highest TSS/TTA ratio (1.95). The harvest date did not affect firmness or calcium concentration.