Effect of timing of mineral oil spraying on budburst and metabolic changes in "Barkhar" apple trees under conditions of inadequate winter chilling in Egypt

The impact of mineral oil at completely different dates to work out the foremost effective date for spraying buds of "Barkhar" apple (Malus sylvestris, Mill) trees was investigated. Also, their effects on metabolic changes within the content of buds from chemical substances throughout their release from dormancy were detected. The potency of early bud break was noticed in varied degrees with oil at completely different dates. It fully determined that the applied treatment at completely different dates results in early bud break, short flowering length, high percentages of bud break, fruit-set, yield/ tree(kg), yield parts (number of fruits per tree, fruit weight, fruit size , fruit length and fruit width). Also as high contents of some chemical constituents of fruits (total soluble solids (TSS) and vitamin C) and low content of total acidity with the appliance of the various dates. Additionally, high contents of buds from water content, total carbohydrates, total sugars, total indoles, indole-3-acetic acid, gibberellin, total free amino acids, total flavonoids, total and conjugated phenols, as well as, low content of non-soluble carbohydrates, abscisic acid and free phenols were achieved.