Growth Response and Selenium and Boron Distribution in Broccoli Varieties Irrigated with Poor Quality Water

Abstract

Selenium (Se), and boron (B), and salinity contamination of agricultural drainage water is potentially hazardous for water reuse strategies in central California. This greenhouse study assessed tolerance and Se, B, and chloride (Cl−) accumulation in different varieties (Emerald City, Samurai, Greenbelt, Marathon) of broccoli (Brassica oleracea L.) irrigated with water of the following different qualities: (1) non‐saline [electrical conductivity (EC) of <1 dS m−1]; (2) Cl−/sulfate salinity of ∼5 dS m−1, 250 µg Se L−1, and 5 mg B L−1; and (3) non‐saline and 250 µg Se L−1. One hundred and ten days after transplanting, plants were harvested and dry weight (DW) yields and plant accumulation of Se, B, and Cl− was evaluated in floret, leaf, and stem. Irrespective of treatments floret yields from var. Samurai were the lowest among all varieties, while floret yields from var. Marathon was the only variety to exhibit some sensitivity to treatments. For all varieties, plant Se concentrations were greatest in the floret (up to 51 mg kg−1 DW) irrespective of treatment, and B and Cl− concentrations were greatest in the leaves; 110 mg B kg−1 DW and 5.4% Cl−, respectively. At post harvest, treatment 2 (with salinity, B, and Se) increased soil salinity to almost 6 dS m−1, total Se concentrations to a high of 0.64 mg kg−1 DW soil, and water soluble B concentrations to a high of 2.3 mg B L−1; soluble Se concentrations were insignificant. The results indicate that var. Emerald City, Greenbelt, and Marathon should be considered as recipients of moderately saline effluent enriched with Se and B under field conditions.