The Effect of Plant Pruning on Yield and Fruit Quality of Eggplant (Solanum melongena L.) in Greenhouse Cultivation

The aim of the investigations was to determine the method of eggplant (aubergine) pruning, optimizing the proportions between vegetative and generative plant development. The investigations were carried out in 1999-2001 in the experimental greenhouse of Agricultural University in Krakow, Poland. 'Tania F₁', cultivar 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. The plant shape modified the photosynthetically active radiation (PAR) conditions in the plant profile. Plants pruned to two shoots received meanly 22% less of PAR in comparison to plants pruned to one shoot. Among the treatments the most beneficial light conditions were observed in treatments pruned to one shoot with two fruit sets per node. Pruning strongly affected the effectiveness of fruit setting, especially in treatments pruned to two shoots. Plants pruned to two shoots with one fruit set and three leaves per node set fruits the most evenly on subsequent nodes. With this pruning system the vegetative and generative eggplant development was balanced in the highest degree. Intensive plant pruning did not reduce the eggplant yield in the present experiment. Also earliness of production was not affected by the systems of pruning. Mean early yield from first four harvests was 4.06 kgㆍm-² (total) and 4.04 kgㆍm-² (marketable) without statistical differences among treatments. Also total (10.44 kgㆍm-²) and marketable (9.41 kgㆍm-²) yield was not affected by the pruning system. Plants pruned more intensively (one shoot, two fruit sets per node) produced more I class fruits. Less intensive pruning resulted in the increase of the number of unmarketable fruits. Pruning affected fruit qualities, assessed on the base of dry matter, total sugar, vitamin C, and chosen element contents.