Fruit Quality of Spur-Type and Nonspur-Type ‘Delicious’ Apple Strains

Abstract

Six strains of ‘Delicious’ apples ( Malus domesticaBorkh.) were evaluated over four seasons for color (peel and flesh), flesh firmness, soluble solids content (SSC), titratable acidity (TA), individual and total carbohydrate content and disorders. Fruit were evaluated at harvest and after controlled atmosphere storage. Strains were grouped based on spur-type (‘Starkrimson’, ‘Starkspur Ultrared’, ‘Oregonspur II’) vs. nonspur-type (‘Early Red One’, ‘Topred’, ‘Classic’) growth habit and compared. Spur-type apples as a group were more mature at harvest, but contained both less peel red color and less TA than non-spur-type apples. After CA storage, spur-type apples were firmer with a higher SSC/TA ratio despite significantly lower SSC and TA values. Spur-type fruit also displayed a more green-colored flesh and little or no peel color difference depending on storage term. Nonspur-type ‘Delicious’ apples from both WA and ID had higher sucrose content per gram of flesh than spur-type apples. The proportion of the total carbohydrate content made up of sucrose was consistently greater for nonspur-type vs. spur-type fruit in both locations.