Population density and substrate volume on tomato seedlings (Lycopersicum licopersicon Mill.)
In conventional tomato (Lycopersicum licopersicon Mill.) nurseries, with the use of trays of small cavities, the seedlings suffer physiological and morphological negative effects in response to mutual shading caused by high density of seedlings and reduction of volume for root growth, factors which are exacerbated at the end of the nursery stage. The aim of this study, in a greenhouse, was to evaluate the effects of population density and substrate volume in nursery on growth and development of tomato seedlings, Charleston cultivar, and after transplanting, on the number of flowers of the three first inflorescences as a strategy to increase performance under a production system based on three clusters per plant. The experimental design was a randomized complete block with a factorial 24 arrangement: the combination of four densities of plantation (480, 720, 960 and 1200 seedlings m-2) and four volumes of substrate (12.3, 36.8, 61.4 and 85.9 cm3) defined by its depth. In nursery the substrate was a mixture of perlite: vermiculite 1:1 (v/v). A variance analysis was performed and treatment means were compared using the Tukey test (p≤0.05). Seedling height and number of leaves were higher in the lowest density (480 seedlings m-2) 37 d after sowing. The highest density (1200 seedlings m-2) caused a lower foliar area and biomass of stem, roots and total in the seedlings, as well as a decrease in the number of fruits in the first cluster. The containers with volume of 12.3 cm3 reduced the seedling height and the number of flowers in the first inflorescence, respect to containers of 85.9 cm3. It is concluded that seedling vigor can be increased by reducing sowing density which increases number of flowers and fruits in plants with a three clusters system.