Observations were carried out in the eastern part of Hungary. In this experiment we studied the nutrient supplyreaction of four apple cultivars (Golden Delicious, Granny Smith, Idared and Jonathan Csány) under different Nand NPK-doses. The following fruit quality parameters were detected: fruit diameter, fruit height, fruit weight, fl esh fi rmness, 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 fl esh fi rmness of cultivars, that has a negative effect on storageability.
