Efficacy of 1-methylcyclopropene in promoting shoot growth of tomato transplants

D.I. Leskovar, Y. Othman
The ethylene inhibitor 1-methylcyclopropene (1-MCP) is commonly used to increase the shelf life of fruits. However, the application of 1-MCP to modulate the shoot growth of vegetable transplants is unknown. The objective of this study was to assess the influence of 1-MCP on improving the growth and quality of tomato transplants. Eight tomato cultivars ('Florida 47', 'Shanty', 'Volante', 'Tycoon', 'TAMU-Hot', 'Felicity', 'Charger', and 'BHN685') were grown in greenhouse conditions for seven weeks and then 1-MCP (50 mg L-1) was applied to transplants using a boom fertigation system. After treatments, both the 1-MCP and untreated plants were transferred to 0.5-L pots and placed in three growth chamber environments differing in day/night temperature regimes, 30/20°C (optimum), 34/24°C constant (stress) and 34/24°C ramping (stress). The plant morphology and physiology variables were collected during the study period. 1-MCP application significantly increased the leaf area, stem diameter and plant height of 'Florida 47' across all temperature regimes. 'TAMU-Hot', which was grown only in the 34/24 environment (ramping) also positively responded to 1-MCP. However, the leaf gas exchange (photosynthetic rate and stomatal conductance) and SPAD measurements were inconsistent across cultivars. 1-MCP had no negative effect on the transplant growth across all cultivars in the 30/20 environment but reduced growth components in Felicity and Tycoon in the 34/24 environment. Our results showed that the application of 1-MCP to improve the transplant quality is promising. Since genetics and environment may influence the sensitivity of tomato plants to 1-MCP, future studies should aim to identify the optimal microclimate growth conditions for specific cultivars.
Leskovar, D.I. and Othman, Y. (2018). Efficacy of 1-methylcyclopropene in promoting shoot growth of tomato transplants. Acta Hortic. 1204, 229-234
DOI: 10.17660/ActaHortic.2018.1204.30
1-methylcyclopropene, gas exchange, ethylene, temperature stress

Acta Horticulturae