Evaluation of Cucumis sativus ontogeny in open field, low, medium and high cost greenhouses in warm tropical regions of Ecuador

In the warm coast of Ecuador, cucumbers are grown in soil systems and open field. They present very low yields due to the long period of heavy rainfall and the presence of pests and diseases. The cultivation under protection and using a soilless system could be a solution to increase yield. The ontogeny of the Cucumis sativus cultivar 'Diamante' has been evaluated in four plots of 2400 m2 each from October 3 to December 13, 2011. Specifically there were three protective structures differing in cost due to the number of windows in each (high cost (HC) with soilless system, medium cost (MC) with soil system, low cost (LC) with soil system and an open field cultivation (OF) system). The protective structures were multi-tunnels greenhouses with 5 tunnels, 8 m wide each. The roof cover was a three layer co-extruded film stabilized with Hindered Amine Light Stabilizer (HALS) and antioxidants of 200 µm. The sidewalls of the greenhouses were covered with anti-insect nets. HC and MC presented a height of 4 m under gutter and 5 m at the ridge. HC had 10 motorized and automated roof windows (1×0.60 m2); MC had 5 roof windows with manual management. LC presented a height of 3 m under gutter and 4 m at the ridge and it did not have roof windows. In all plots the same cultural techniques were used. The morphological parameters measured were plant height, stem diameter, number of leaves, leaf width and length, dry and fresh weight. The reproductive parameters measured were number of flowers, number of fruits per plant, fruit diameter, soluble solids content and crop yield. Overall, all morphological parameters of the cucumber plants grown under protection were significantly better than those growing in OF. The highest yield (3.3 kg m-2) was obtained with the HC structure and soilless system, and the lowest yield (2.7 kg m-2) was found in OF with soil system.