Morphophysiology and postharvest quality of hydroponic lettuce cultivars grown under high temperature

Abstract

ABSTRACT Lettuce (Lactuca sativa) is the most economically important leafy vegetable in Brazil, with the crisp type being the most popular among producers. However, in regions with hot climates, lettuce has production limitations due to bolting, requiring knowledge on the behavior of cultivars available on the market. Thus, the objective of the present study was to characterize the performance of crisp lettuce cultivars in terms of their productive, physiological, and postharvest quality aspects when grown under hydroponic cultivation and high temperature conditions. The assay was performed in a greenhouse and the plants were grown in a hydroponic system of DFT type. The average temperature during the experiment was 30.33 °C. The experimental design used was completely randomized with nine treatments (Veneranda, Cristina, Olinda, Mônica, Cinderela, Grand Rapids, Itapuã Super, Crocantela, and Simpson Black Seed), with four replications. The cultivars were analyzed in terms of their productive, physiological, and postharvest quality performances. The Olinda and Cristina cultivars showed the best performance in growth, physiological, and postharvest variables. However, the cultivars had distinct sensory characteristics. Bolting negatively affected gas exchange, production, and postharvest quality of lettuce cultivars Veneranda, Mônica, Grand Rapids, and Cinderela. In addition, it was observed that the pigment content was not determinant for the expression of bolting. Therefore, this study recommends the use of cultivars Olinda and Cristina for the hydroponic cultivation under high temperature conditions.