DETERMINATION OF PRACTICALLY IMPORTANT MATURITY INDICES FOR SOME APPLE VERIETIES RECOMMENDED FOR COMMERCIAL PRODUCTION

 To meet OECD’s requirements on starch staining test standards and to bring about the relationship among three practically important maturity tests; ‘starch staining’, ‘firmness’, and ‘soluble solids (ss)’, studies were conducted between 1996-98 as the third step of the continuous project on two very early (VISTA BELLA, JERSEYMAC) and one mid-season (OZARK GOLD) and three late maturing (MELROSE, GLOSTER 69, SKYLINE SUPREME) varieties of apples. The picking started earlier and were sustained until fully drops took place, variety specific starch standards were developed and on four varieties (OZARK GOLD, MELROSE, GLOSTER 69, SKYLINE SUPREME) maturity related storage experiments were carried out. Observed eminent maturity variations even on the same bud clusters in the two early varieties (VISTA BELLA, JERSEYMAC) oriented studies to whole-tree picks and in conclusion, it was found that the blush color (over-color) is a more reliable index for determining maturity that the others. OECD and TSE standards were used for quality criteria of the apples. Several picks of apples having blush-color at 30-50% is necessary for near and distant markets. On OZARK GOLD 12 picks were made and four large-scale picks confined to maturity/storage experiments and the variety was found to be a long storing one if harvested at suggested starch scale and firmness. The storage potential of OZARK GOLD is about 5-6 months at 0ºC. For MELROSE starch test was found to be as most dependable as the firmness test and it was additionally found that late picking eliminated the storage scald in this variety leaving storage potential of 5-6 months. GLOSTER 69 is a long storing late variety if picked rather early and starch test is the most reliable parameter for maturity. Studies on SKYLINE SUPREME included three picks and one (early) pick for storage experiment in 1996 and one late pick for storage experiment in 1997. Although starch test seemed a very reliable index for this variety storage experiment demonstrated the fact that the fruit should be entirely covered by over-color (red) to eliminate the hazard of ‘storage scald’. Therefore, growers should delay the harvest until full color is well established on this variety.