Role of tree elicitor treatment on crop yield and pomegranate fruit quality parameters and bioactive compounds

Pomegranate is an ancient edible fruit with high-quality properties and antioxidant compounds with beneficial health effects. ‘Mollar de Elche’ is the most cultivated pomegranate cultivar in Spain, which consumers appreciate since its arils have a high concentration of sugars, low acidity and small and soft seeds that can be easily eaten. However, the anthocyanin content in the skin and flesh of the ‘Mollar de Elche’ is not as high as other worldwide-known cultivars, such as ‘Wonderful’; its arils are slight red-coloured, and the skin has a cream-pink colour. This low colouration of skin and arils makes it difficult for this cultivar to reach international markets. On the other hand, pomegranate exhibits important quality losses during postharvest storage, the most important being fruit water and firmness losses and reduction in aril acidity, which lead to a reduction of fruit acceptability in terms of freshness, juiciness, and taste. Thus, the present keynote will be focused on showing recent results of our research group regarding the beneficial effects of preharvest treatment with methyl jasmonate, salicylic acid and its derivatives and melatonin on pomegranate quality parameters, at harvest and during storage, with a special interest in aril colour and content on anthocyanins, since they are important antioxidants with beneficial health effects. In addition, this paper includes comments on the effects of these treatments on on-tree fruit ripening and crop yield.