Quality of Apple Fruit from a High Density Orchard as Influenced by Rootstocks, Fertilizers, Maturity, and Storage

Fruit quality of ‘Starkspur Golden Delicious’ apples ( Malus domestica Borkh.) on 6 rootstocks [Seedling, Mailing (M) 1, M ailing Merton (MM) 106, M 7, OAR 1, M 26] grown in a high density orchard at 2 levels each of K and N was studied at 3 harvest dates and after 6 months of 0°C storage from 1980 to 1982. Fruit on OAR 1 rootstock had greater soluble solids, more yellow color at harvest and after storage and were relatively firmer at harvest, but were smaller than those from other rootstocks. Fruit on M 7 had lower soluble solids than most of the other rootstocks at harvest time. Fruit from MM 106 had a lower incidence of breakdown in storage than most others. Crop load influenced both harvest and storage quality. Fruit on M 26, which had a light crop in 1981, were larger, yellower, and had higher soluble solids, and also had more storage breakdown (about 20%) and bitterpit (about 12%) than other rootstocks. Rootstocks or fertilizers did not affect fruit respiration. Little effect of K fertilizer was found on any quality indices, whereas high N treatments produced greener fruit than did low N.