Postharvest commercial quality improvement of broccoli (Brassica oleracea L.) after foliar biofortification with selenium

Broccoli heads (Brassica oleracea L. var. italica Plenck) are one of the most valuable vegetable crops parts due to their high nutritional content. Nevertheless, they are quickly decomposed during postharvest, with the consequent loss of commercial quality. Several postharvest treatments have been analyzed to delay this process, but the influence of preharvest treatments has been little studied. Previously, we have examined the effect of foliar application of sodium selenate and selenite (50 and 100 g ha(-1)) on selenium accumulation and commercial quality of broccoli at harvest time. Here, we analyze the effect of these preharvest treatments on postharvest shelf-life of broccoli grown under field and pot conditions, in "Belstar" and "Legend" cultivars. Examination of the external appearance of the heads, quantified by Hue and L parameters, showed a marked delay in yellowing in treated samples compared to controls. In addition, selenium treatments mostly maintained the firmness and diameter of the heads. Similar results were obtained for both growing conditions and cultivars. Noticeably, the nutritional composition of broccoli heads was maintained or even improved after several foliar treatments with selenium compared with the control ones. Finally, the same analysis was performed in broccoli heads stored at low temperature, also showing different parameters improvement in the selenium-treated groups compared to control. So, we can conclude that foliar selenium treatment, besides being an overcoming strategy to obtain selenium-enriched broccoli, also contributes to improving the quality of heads during postharvest.