Interference of cultivar and ways of cultivation in lettuce (Lactuca sativa) yield and conservation

This study aimed to measure the yield and postharvest conservation of three lettuce varieties (Crisp, Mimosa, and Iceberg) grown in two different cultivation systems (Conventional and Hydroponic) and stored under two conditions (Ambient temperature and Refrigerated). The experiment used a randomized design with tree factors (cultivars, cultivation systems and storage types) and 4 repetitions. The samples were collected randomly, in the city of Francisco Beltrão-PR, Brasil, from a local producer. The yield (head diameter, leaf size, number of leaves, stem length and fresh weight), the physicochemical characteristics (moisture, ash, soluble solids, pH, titratable acidity, fiber, vitamin C and nitrate), and post-harvest conservation (color/darkness and occurrence of post-harvest rots) were evaluated. The results showed that lettuce from conventional cultivation had the highest yield. The physicochemical parameters presented different behaviors related to cultivars and cropping systems. The lettuce of conventional cultivation presented higher content of minerals (ash) and vitamin C. On the other hand, the hydroponic cultivation proved to be more efficient in post-harvest conservation. The refrigerated environment proved to be more suitable for the conservation of vegetables, since they presented a better overall appearance. Storage at ambient temperature, in turn, contributed to greatest deterioration of the plants.   Key words: Lettuce, cultivation systems, cultivate, pos-harvest conservation, fresh produce, refrigerated.