Evaluation of Quality Traits and Yield of 28 Strains of ‘Delicious’ Apple

Abstract

Traits contributing to yield and fruit quality of 28 spur and standard growth habit strains of ‘Delicious’ apple ( Malus domesticaBorkh.) were studied. Cumulative per tree yield to seventh leaf (precocity) was consistently greater in the spur strains averaging 33.7 kg compared to 20.4 kg for standard strains. Mature tree yield was nearly equal for the two tree types but average yield efficiency was higher for the spur strains. This was reflected in higher calculated per hectare yields (45.1 compared to 28.8 tonnes). Color and size grades were determined on a commercial grading line. The standard strain ‘Early Red One’ was notable as the best coloring strain and also had a higher efficiency ratio than other standard strains in the fifth crop. Color of strains ranged from a high of 59% to 0% (B.C. extra fancy) with most spur strains developing less color than standard ones; but the spur strains ‘Ace,’ ‘Red King Oregon Spur’ and ‘Improved Ryan Spur’ were highly ranked for color. The spur strains with poorer color also had smaller fruit. ‘Red King Oregon Spur’ and ‘Aomori’ had larger fruit than other strains. Fruit shape, seed number, soluble solids and flesh firmness of strains varied less than color and yield determining traits.