The Effect of Plant Pruning on the Light Conditions and Vegetative Development of Eggplant (Solanum Melongena L.) in Greenhouse Cultivation

The aim of the present investigations was to find the relations between pruning methods and chosen parameters of vegetative eggplant development in greenhouse conditions. The plant shape modifies the photosynthetically active radiation (PAR) conditions in the plant profile. Independence between different pruning methods and vegetative plant development particularly leaves characteristics as well as pigments and photosynthesis products content in leaves was stated. The investigations were carried out in 1999-2001 in the experimental greenhouse of Agricultural University in Kraków, Poland. Eggplant of Tania F₁ hybrid was used in the early spring-summer production in a heated greenhouse. The following pruning systems were applied: pruning to one shoot with leaving on every node 2 fruit sets and 1, 2 or 3 leaves, and pruning to two shoots with leaving on every node 1 fruit set and 1, 2 or 3 leaves. With the introduction of a greater number of leaves and fruit sets on eggplant shoots irradiation in plant profile was reduced. The value of leaf area index (LAI) depended on the way of pruning. Chemical composition of leaves was slightly dependent on the method of pruning only in the case of assimilation products, i.e. reducing sugar and starch. Improvement of photosynthesis efficiency of intensively pruned eggplants was achieved by the increase of single leaf area and thickness of leaf mesophyll tissues without the increase of the level of assimilative pigments per plant mass unit.