Zinc sources in enrichment and yield of lettuce cultivars

Abstract

Zinc is an important element of plant metabolism, playing roles in several enzymatic reactions. Biofortifying
lettuce with Zn is a strategy to meet the demand for this nutrient via food. This work aimed to evaluate the effect
of foliar fertilization with different sources of zinc on the agronomic biofortification of special lettuce cultivars
under low-altitude tropical conditions. The experiments were carried out in two seasons in a randomized block
design, in a factorial scheme (4 x 3) + 1, composed of four lettuce cultivars (SVR 2005®, Romanela®, Crocantela®,
and Rubinela®), three sources of Zn (Zn sulfate, Zn oxide, and Zn chelate), and a control without zinc application,
with four replications. The following characteristics were evaluated: head diameter (in cm); fresh leaf mass
(in g plant-1); head volume (in cm³); yield (in t ha^-1), and Zn content (in mg kg^-1). The special lettuce cultivars
presented head diameters within the commercial requirement. ‘Romanela’ showed the best results for head
diameter, head volume, number of commercial leaves, fresh leaf mass, and yield. The Zn oxide was the best
source to biofortify the special lettuces with foliar content of 260 mg kg^-1 for ‘Rubinela’.