Paclobutrazol as a seed treatment for raising greenhouse seedling plug of processing tomatoes, was tested for improved seedling vigor, higher transplanting stress tolerance under low temperature (spring) conditions and earlier harvest maturity in France. Seedlings of the cultivars Fancyset, Pavia and Montego were raised in a greenhouse in Nimes and field tested in the cold zone of Marsanne during the 1999 growing season. Paclobutrazol-treated seed was also evaluated to grow vigorous bare root seedlings in mini plastic tunnels, in a field nursery in Pierrelatte. Significant differences were recorded with Paclobutrazol-treated seedlings plugs which at 6 weeks were 43% shorter in seedling height, 9% thicker stem diameter and 6% higher dry matter. However, reduced seedling emergence with Paclobutrazol-treated seed was evident, ranging from 12% (Fancyset) to 25% (Pavia) reduction, as compared to the non-treated checks. Significant yield increases of 13% due to the Paclobutrazol treatment were recorded, together with earlier harvest maturity by 6%. Bare root seedlings raised in mini plastic tunnels in the field from Paclobutrazol treated seed were shorter and thicker, measuring 23.4 cm in height as compared to 30.5 cm in the checks, at 10 weeks. Future trials are planned on a larger scale in farmers' fields, in different regions and with other cultivars.
