Increasing Yield and Quality of Tomato Cultivated Under High Temperature Conditions Through the Use of Elicitors

Abstract

Increased air temperature is one of the factors associated with global climate change that may largely affect productivity and quality of horticultural crops. In tomato, in particular, high temperature stress causes flower abortion and limits fruit set, leading to major losses in yield. Moreover, increased temperature can modify tomato quality by altering the physical properties (size, colour, etc.) of the fruit, as well as the sensorial and nutritional quality. Elicitors are molecules which, at low concentrations, induce plant defence systems by promoting the synthesis of biologically active metabolites. The plant response induced by the application of an elicitor, can affect tolerance to other non-related abiotic or biotic stresses (cross-tolerance). In this research, the effect of the application of different elicitors on the productivity and quality of tomato cultivated under high temperature conditions was examined. Plants were grown in south-eastern Spain under greenhouse conditions in the winter to summer season. During the fruiting period, day temperatures inside the greenhouse reached 42°C. Plants were sprayed 110 days after transplant and 5 and 11 days after the first application, with a suspension of methyl jasmonate (MJ) (100μM), salicylic acid (SA) (200μM), chitosan (CH) (1g L-1) or 2,4-epibrassinolide (BRs) (30μM). Control plants for each elicitor treatment were sprayed with the same wetting agent as treated plants. Only treatments with SA and BRs increased significantly total fruit yield, as a result of the increase in fruit number compared with control plants. No significant effect of the treatments was observed on fruit weight, regardless of the treatment. In addition, MJ and SA treatments increased the value of the red/green colour component (a*) indicating an enhancement of the tomato red colour. In view of the results, the application of elicitors could be considered a potential tool for increasing tomato fruit yield and quality under high temperature conditions.