Improving the foliar biofortification of broccoli with selenium without commercial quality losses

Abstract

Selenium-biofortified broccoli (Brassica oleracea L. var. italica Plenck) is an important source of micronutrients in a healthy human diet. Therefore, studies are needed on the commercial production of selenium-enriched broccoli. We analyzed the effect of the foliar application of sodium selenate and sodium selenite in doses of 50 and 100 g ha−1 on the growth, photosynthetic parameters, selenium accumulation, and commercial quality of broccoli in two cultivars (‘Belstar’ and ‘Legend’) used for fresh crops market grown under field conditions. The application of both doses of selenate and the highest dose of selenite induced a significant increase in the head fresh weight (FW) only in cultivar Belstar. However, the dry matter content of the heads was not significantly affected by selenium or the cultivar of broccoli. In addition, the increase in the water use efficiency, mainly due to the reduction of the transpiration rate, could explain the significant increase in the head FW without modifying the head dry matter content in Belstar. On the other hand, selenium treatments before harvest maintained the green color and did not affect the firmness and diameter of the heads at harvest. The selenium content of the heads increased markedly in a dose-dependent manner in both cultivars, with both selenium treatments. The results of this study indicate that the response to selenium treatments differs between broccoli cultivars and that the use of both selenium salts in foliar form would be a good strategy to obtain selenium-enriched broccoli, without affecting the commercial quality of the heads.