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.

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

“…It is known that broccoli harvest also affects head diameters with an increase due to florets opening, as part of the tissue decay and disorganization (Dixon, 2007). However, the diameter of broccoli heads was not significantly affected by Se foliar application at the harvest time; while the diameter ranges obtained were similar to previous reports (Ghasemi et al., 2016; Muñoz et al., 2021). Foliar application of Se salts, improved head diameter maintenance during postharvest, likewise the previous results.…”

“…In our previous work, we have reported that foliar application of Se salts at preharvest did not affect head firmness at harvest (Muñoz et al., 2021). In this work, a delay in the reduction of broccoli heads firmness, and even an augment in particular cases, during postharvest life, has been established.…”

“…Hue angle ( h °) was calculated as h ° = tan −1 ( b */ a *) when a * and b * > 0, or as h ° = 180° − tan −1 ( b */ a *) when a * < 0 and b * > 0, as previously described Muñoz et al. (2021).…”

“…Foliar application of Se was carried out following the method based on Muñoz et al. (2021). Briefly, spray solutions of 0, 25, and 50 g ha −1 of selenate or selenite (Na 2 SeO 4 , Na 2 SeO 3 , Sigma‐Aldrich) in distilled water containing 0.1% Rizospray Extremo ® , a commercial adjutant which formulation includes organosilicons and fatty acid methyl esters of vegetable oils (http://www.rizobacter.com.ar/en/productos/argentina/rizospray-extreme), were applied at the beginning of head formation.…”

“…We have previously reported the impact of foliar application of different Se mineral forms (sodium selenate and sodium selenite) at two different doses (50 and 100 g ha −1 ), and the additional use of an adjuvant, on broccoli plants grown under field conditions (Muñoz et al., 2021). The results indicated that the use of both Se salts could be an overcoming strategy to obtain Se‐enriched broccoli, without affecting, at harvest time, the commercial quality of the heads (Muñoz et al., 2021). The objective of this work was to analyze the effect of these two Se salts on the postharvest shelf‐life of broccoli heads quality, regarding both commercial and nutritional parameters.…”