Evaluation of the influence of irrigation and fertilization on the content of some biochemical colour compounds in tomatoes, greenhouse production by mathematical approach

Using a mathematical approach (correlation and cluster analysis), assess the similarity and remoteness of different irrigation regimens for tomatoes and group them on the basis of basic biochemical parameters. The objectives of the study was to establish the parameters of the quality indicators (common dyes, lycopene and beta-carotene) in tomato under the influence of the various irrigation and diets; to compare the similarity and remoteness of different irrigation regimes and fertilization regimes for tomatoes, the variety Vitelio F1 and to group them on the basis of important quality indicators using cluster analysis and to establish correlation between study quality indicators to make a more objective assessment of the studied factors - irrigation and fertilization. As a result of the analyses the effects of irrigation regimes and the rate of fertilization in tomatoes are found. At all fertilization levels, there is a tendency to increase the lycopene content by decreasing the irrigation rate. The same trend is observed in the content of beta-carotene in tomatoes. Increasing the water deficit increases the levels of beta-carotene. Cluster analysis divided the similarity in the two main cluster variants. In the first cluster it is comprised of two sub-clusters: the first sub-clusters with variants 2, 3 and 1, the second sub-clusters to the embodiments 5 and 6, similar indicators, common dyes and beta-carotene and variants impaired irrigation regime and with at least Euclidean distance between them. The second major cluster includes variants 7, 10, 8, 9 and 11 where it is allowed a small to moderate water deficit. They are most similar to common dyes, lycopene and extraction. The strongest positive correlation is found between total dye and lycopene, betacarotene, yield.