Growth, development and dry-matter distribution of a tomato crop as affected by environment

Greenhouse tomato plants, cvs Carmen and Diva, were grown during autumn and winter in two non-heated polyethylene greenhouses having similar values of incoming solar radiation and different air temperatures. Daily radiation fell to values blow 8.4 MJ m(-2) day(-1) after the 131 d from sowing. Daily amplitude of air temperatures differed by 3.8 K between greenhouses when minimum air temperatures were higher than 18 degrees C. Periodically destructive measurements were conducted for a period of 154 d from sowing to determine the number of leaves, trusses and developed fruits per plant, leaf area and dry matter of shoot organs. The number of leaves preceding the first inflorescence varied between 4 and 6, suggesting this variable is negatively correlated with radiation, but positively with temperature. The number of leaves decreased after the 130 d from sowing while the number of fruits per plant continued to increase during the same period. Total dry matter was similar in both greenhouses, despite the differences in numbers of leaves and fruits per plant. The fraction of dry matter in fruits was low, always below 40%. Exponential functions were fitted between vegetative dry matter and fruit dry matter and also between total and fruit dry matter content. When radiation became low, growth of fruits was greater relative to the vegetative plant parts. Growth of fruits was dependent on assimilate supply by leaves, and this dependence should be considered in modelling the assimilate partitioning of a tomato plant.