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• Partial and total rejuvenation pruning of sour cherry trees

  11-15.

  Á. Csihon

  P. Dremák

  I. Gonda

  Views:

  322

  Sour cherry can be considered as a special fruit species regarding the growing characteristics, as most of the cultivars are characterized by strong balding. With the aging of the tree the inactive (passive) parts of the canopy are increasing steadily, so the productive cropping surface and the yielding capacity decrease  significantly. In our experiments partial rejuvenation pruning was carried out in a 12 years old orchard, and total rejuvenation pruning was performed in a 21 years old plantation to regenerate the cropping surface of the trees. Thanks to the latter one the canopy of the sour cherry trees were regenerated during only two years. The yields of the rejuvenated trees in cv. ‘Debreceni bőtermő’ exceeded the yields of the control trees, as in the case of the cvs. ‘Érdi bőtermő’ and ‘Újfehértói fürtös’ approached it. At the same time the total rejuvenation pruning has a positive effect on the fruit size.

• The role of rejuvenated and adult forms of English oak (Quercus robur) in in vitro cultures

  81-83.

  Gy. Végvári

  I. Balla

  Z. Kothencz

  Views:

  169

  In vitro plant material of clones (Q. robur) NL 100 A (adult) and NL 100 R (rejuvenated) received from Germany (A. Meier-Dinkel, 1995) were used in these experiments. WPM medium was used for the multiplication phase. Plantlets were subcultured monthly. Differences in quality and colour of the adult and rejuvenated cultures induced us to follow and compare the changes of mineral- and chlorophyll content and dry weight during the propagation phase. Mineral and chlorophyll content as well as dry weight were measured weekly on three samples during the subculture period.

  In the case of propagation rates we stated, they were similar around the year, but both clones had a high peak in April. Examining the cation-content, we detected that, the plantlets had a highest quantity of several elements during the 2nd and 3rd week of subculture. The iron content was the highest in the 1st week and after that it decreased continuously. It is supposed, that the content of iron is not enough in the media. The chlorophyll content of the rejuvenated clone was higher than that of the adult one.

  In the rooting experiments it was stated that, after one-week cold treatment the rooting ability was the best.

   

• Training and maintaining spindle crowns in cherry production

  51-53.

  B. Vaszily

  I. Gonda

  Views:

  261

  In cherry production all over the world, intensification of the technology is the main objective of research. Small crowns and high planting densities are aimed to attain high yields per hectare and easier harvesting. Rootstocks of reduced vigour for cherries are more difficult to find than in other fruit species, and the rejuvenation of fruiting structures by pruning is aggravated by the reduced vigour. Intensity of the technology ought to be achieved by a thoughtful application of the technological elements (timing of pruning by various intensity) moreover, by finding different policies for individual varieties. Sweet cherry varieties dominating the assortment proved to be very variable regarding their growing habits. In our experiment, we dealt with the slender spindle and free spindle forms, and how to train the trees to develop and to maintain the desirable form depending on the respective variety in order to achieve the right load of flower buds and yields repeatedly. In this paper, we examine the most important practical issues with the training and maintaining of the crowns of cherries with circular projection and central axis grafted on Prunus mahaleb rootstocks

• A study of processes active in regeneration of different sweet cherry varieties

  55-57.

  B. Vaszily

  Views:

  232

  Cherries belong to the group of fruit trees, which require little attention in pruning. The process of getting bald branches is less accentuated, which is associated with the light requirement of organs changing along with the aging process. The growing habits of the varieties (length and number of growing shoots, etc.) is closely related with the productivity of fruiting parts. The ability of regeneration and the functional effectiveness of fruiting structures are expressed by the distribution according to their age. The differences registered justify the necessity to develop pruning policies for each particular type of variety. For that purpose, we have to examine the age dependency of the processes related to regeneration, which may serve as starting point of a pruning strategy. Growth of some parts should be stimulated in order to develop or regenerate fruiting parts. Some branches need to be rejuvenated, partially, as an antidote to progressive senescence. Every intervention is aimed to strengthen the development of the most productive constructions. Reactions induced by rejuvenation should be expressed in fruiting intensity. A pruning program adapted to the particular variety as well as to the actual phase of a rotating pruning system should anticipate results.