IMPACT OF WATER DEFICIT ON SENSORY PROFILE OF TOMATO (Solanum lycopersicon L.) GROWN UNDER HOT SUMMER CONDITIONS IN BULGARIA

The effect of water deficit on sensory characteristics of tomato (Solanum lycopersicon L.) was investigated. A field experiment was carried out during 2016-2017 period under the hot summer conditions in Bulgaria. Twenty four Bulgarian tomato accessions representing three types - indeterminate, determinate for processing and determinate for fresh consumption - were harvested. Optimum and 50% reduced watering regimes were applied using a drip irrigation system. Temperatures over 35ºС during the vegetation were recorded in 26% of the days of the first experimental year and 40% of the days of the second one. The sensory analysis of the tomato fruits was performed by trained panelists on the traits: appearance, shape, external colour, internal colour, aroma, peel tenderness, visible fibre, sourness, sweetness, texture and overall taste. Negative effects of the deficit irrigation were observed on the appearance, shape and total sensory evaluation of tomato fruits regardless of the tomato type. Negative effects were also recorded on the texture of determinate tomato for processing and peel tenderness of determinate tomato for fresh consumption. The sweetness was better expressed in tomatoes grown under water deficit in all studied genotypes. Reduced irrigation did not result in aroma, external colour and visible fibre. Two-way analysis of variance revealed a significant influence of genotype on the sensory traits in the range of 39.56-74.79% in indeterminate tomato accessions, 33.49 - 56.05% in determinate tomato for processing, 14.96 - 62.93% in determinate tomato for fresh consumption. Slight influence of the applied watering regime was established except for appearance, shape and sweetness. Indeterminate tomato accessions Rozovo sartse and BG 21 β, determinate accession for processing BG 2086 and determinate accession for fresh consumption Marti and BG 252 demonstrated the best sensory profile in both treatments of irrigation.