EFFECT OF NUTRIENT SUPPLY ON FRUIT QUALITY OF APPLE (Malus domestica BORKH.)

Observations were carried out in the eastern part of Hungary. In this experiment we studied the nutrient supply-reaction of four apple cultivars (Golden Delicious, Granny Smith, Idared and Jonathan Csany) under different Nand NPK-doses. The following fruit quality parameters were detected: fruit diameter, fruit height, fruit weight, flesh firmness, colour-cover and we studied the thicket of foliage of trees. The research results showed, that N-fertilization has a great effect on fruit quality. This appears in the cases of increase of fruit largeness. The increase is proportional to N-levels. Moderate N-doses plus PK-addition had also positive effects. The nutrient supply increased vegetative area in addition to the generative parts, in particular pure N fertilizer. But the thicked foliage hindered the growth of fruit weight and colour-cover, also decreased the fruit quality. And decreased the flesh firmness of cultivars, that has a negative effect on storageability.