EFFECT OF FOLIAR-APPLIED GIBBERELLINS AND SOIL-APPLIED PACLOBUTRAZOL ON FRUIT-QUALITY AT HARVEST AND DURING STORAGE OF BRAEBURN APPLES GROWING UNDER A HIGH-DENSITY PLANTING SYSTEM

Five-year-old 'Braeburn/MM.106' apple (Malus domestica Borkh.) trees g rowing under a high-density (10 000 trees/ha) planting system were tre ated with paclobutrazol (PBZ) as a soil drench at 250 mg (a.i.) per tr ee in August 1993. Gibberellin (GA), GA(3) or GA(4), was sprayed on ve getative buds at 0, 10; or 100 mu g per bud at three times between 22 November and 22 December 1992 (before PBZ treatment), or on the same d ates in 1993 (after PBZ treatment). Apples harvested from the experime ntal trees in 1994 and 1995 were evaluated for fruit quality at harves t and during 90 days of storage at 10 degrees C. Time of GA(3) or GA(4 ) application did not affect fruit quality at harvest. PBZ generally i ncreased mean fruit weight the year after and then decreased 2 years a fter PBZ application. Fruit LID ratio was decreased, degrees Brix valu es and fruit flesh firmness were generally increased with PBZ applicat ion to the trees. However, the effects were minor. The addition of GA to PBZ treated trees generally reversed the effects of PBZ. GA(4) was more effective than GA(3) in increasing fresh weight and L/D ratio. Af ter 90 days of storage duration flesh firmness was reduced as an avera ge from 8.4 to 5.2 units, degrees Brix values were increased as an ave rage from 12.9 to 13.2, and average weight loss reached 13 g/fruit. Ti me of GA application, PBZ, or GA did not modify the effects of storage at 10 degrees C.