Nursery Pre- and Post-Transplant Effects on Tomato (Solanum lycopersicum L.) Growth and Yield

Tomato yield are related to genotype and commercial crop technology, which gave a significant range of possible results. The aims of this work were to study the effect of cytokinin sprays (BAP) in pre- and post-transplant as a stress-overcoming factor of the pre-transplant cell size for two tomato hybrids. The hypothesis tested were that the use of plug trays for tomato propagation establish a pre-transplant stress which was amplified during the crop cycle, while a pre- and post- transplant BAP spray let to overcoming the root restriction associated to plug cell size. Our results showed that tomato yield would be increased for determined (‘Argos’) or undetermined (‘Superman’) tomato hybrids using trays with 50 cells. A 100 mg L-1BAP foliar spray increase yield in plants from limited plug cell size as well, although the relative effects are related to when a BAP solution was applied (pre- or post-transplant stage) and the plug size used during the nursery cropping. The plug size-BAP relationship change relative yield in tomato through the relative fruit fresh weight in ‘Argos’ hybrid and both the relative fruit fresh weight and relative fruit number in ‘Superman’ hybrid. Plants from 50-cell tray-1 showed a higher plant size and a different crop architecture which let to explain, partially at least, the higher fresh-dry weight accumulation rate. The higher relative yield would be positively related to relative growth rate between sowing-transplant and a positive feedback in photo assimilates partitioning to plant shoots. Finally, our results showed the mechanisms involved in the plug cell size and BAP relationships, which would be use as a tool for improving fresh tomato yield.