ISHS Acta Horticulturae 224: Fruit Breeding
GENETICAL ASPECTS OF YIELDS AND THEIR QUALITY WITHIN TREE FRUIT CROPS |
| Authors: | J. Blazek, F. Paprštein |
| Abstract:
Yield from a unit of orchard area, influenced by biological material and environmental conditions, depends on the interaction of a number of factors. In the environmental conditions of Czechoslovakia yields of the majority of fruit crops are influenced mostly by frost injuries, especially of generative organs. An average decrease of yield due to frost damage is estimated at about 25% for apples, at least 40% for cherries and more than 50% for apricots and peaches. However, a maximum a half of these losses could be checked by genetic improvement. The second yield component is the health state of the trees. Infestation by diseases and pests can reduce yields of fruit crops dramatically, sometimes to zero. Even in spite of intensive chemical control, the average economical value of yield loss with apples caused by scab is more than 20%. The third most important yield component in fruit crops is fruit set, which mostly depends - especially with stone fruit species - on successful pollination. On the basis of these and a number of other factors an illustrative scheme of the formation of yield for fruit tree crops is suggested. | |
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