Alternate or biennial bearing in fruit trees occurs in different fruit species, amongst them in apple trees. Significant influence on the occurrence of alternate bearing have biotic factors (plant nitrogen-to-carbon ratio, plant hormonal status), abiotic factors (temperature, water availability and its quantity) and flower bud differentiation in the spring. This thesis presents the steps of flower bud differentiation as well as the problematics of biennial bearing and the factors that contribute to it. Plants have some of their own mechanisms to partially control alternate bearing. However, these mechanisms are sometimes insufficient, depending on how prone a certain cultivar is to alternate bearing. In those cases, we have to use certain technological procedures and measures to control it. The thesis details three main thinning methods; chemical, mechanical and hand thinning. Every one of these methods has their advantages and disadvantages as well as different degrees and methods of effectiveness. Biannual bearing can also be controlled by proper care of the trees, such as correct pruning, protection with plant protection products, fertilization, installation of an irrigation systems and anti-hail nets to protect from damage.
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