Variations in yield and gluten proteins in durum wheat varieties under late-season foliar versus soil application of nitrogen fertilizer in a northern Mediterranean environment
BACKGROUND: With the increasing demand for high-quality foodstuffs and concern for environmental sustainability,
late-season nitrogen (N) foliar fertilization of common wheat is now an important and widespread practice. This study
investigated the effects of late-season foliar versus soil N fertilization on yield and protein content of four varieties of durum
wheat, Aureo, Ariosto, Biensur and Liberdur, in a three-year field trial in northern Italy.
RESULTS: Variations in low-molecular-weight glutenins (LMW-GS), high-molecular-weight glutenins (HMW-GS) and gliadins
were assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). It was found that N applied to the
canopy did not improve protein rate compared with N application to the soil (general mean 138mg g 121), but moderately
increased productivity in the high-yielding varieties Liberdur and Biensur (three-year means 7.23 vs 7.13 and 7.53 vs 7.09 t
ha 121 respectively). Technological quality was mainly related to variety choice, Aureo and Ariosto having higher protein rates
and glutenin/gliadin ratios. Also found was a strong \u2018variety
7 N application method\u2019 interaction in the proportions of protein
subunits within each class, particularly LMW-GS and gliadins. A promising result was the higher N uptake efficiency, although
as apparent balance, combined with higher HMW/LMW-GS ratio in var. Biensur.
CONCLUSION: Late-season foliar N fertilization allows N fertilizer saving, potentially providing environmental benefits in the
rainy climate of the northern Mediterranean area, and also leads to variety-dependent up-regulation of essential LMW-GS and
gliadins. Variety choice is a key factor in obtaining high technological quality, although it is currently associated with modest
grain yield. This study provides evidence of high quality in the specific high-yielding variety Biensur, suggesting its potential as
a mono-varietal semolina for pasta production
