SOME ASPECTS OF THE CHANGES IN GROWTH AND CROPPING AS A RESULT OF SOME PRUNING AND TRAINING OPERATIONS IN HIGH-DENSITY APPLE ORCHARDS

1. Objectives and methods

   The effects of shoot tip pinching and of shoot bending were investigated at the Fruit Research Station, Voinesti, Dimbovita in order to determine:-

   • the time taken to produce a new shoot following pinching
   • the extent to which bending reduces shoot growth
   • the combined effects of pinching and bending
   • the pattern and duration of shoot vegetative growth and, following the treatments
   • the effects of the treatments on flower bud formation.

     The work was carried out on the varieties Jonathan, Reine de Reinette, Richared Delicious, Wagener Premiat and Winter Banana.

   • Results, discussion and conclusions

Shoots of Jonathan pinched on June 20 formed new shoots between 5–11 July and by 11 July these were 3.2 cm long (table 1a). Winter Banana produced new shoots more quickly (table 1b), Reine de Reinette rather more slowly and Richared Delicious and Wagener Premiat required 29–30 days from the time of pinching for new shoots to grow (table 1a, table 1b).

When the shoots were bent as well as having their tips pinched there was a delay in shoot regrowth as shown by the shorter shoot length at the time of first measurement.

Bending shoots without pinching out their growing points resulted in greater growth over the first 5 days after bending for Reine de Reinette, Richared Delicious and Wagener Premiat and over the first 10 days for Jonathan. After this shoot growth of the bent shoots was much less than on the controls and the final shoot length was reduced (table 1a, table 1b). The initially greater growth after bending down was probably a reaction response to establish a normal physiological balance. Growth ceased earliest on the bent shoots, then on the bent and pinched ones, then on the controls, then on those pinched only.

The training operations also influenced bud formation on 1-year shoots in the following year (table 2). The control shoots had most dormant buds, Richared and Reine de Reinette having dormant buds in both the lower and upper parts of the shoots. Pinching in the previous year reduced the number of dormant buds at the bottom of the shoots and bending combined with pinching gave the lowest number. None of the Richared shoots formed flower buds whereas all those of Winter Banana,

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