Glutenin composition, quality characteristics, and agronomic attributes of durum wheat cultivars released in Ethiopia

Abstract

Eleven cultivars of durum wheat (Triticum durum L. var. durum Desf.) were evaluated across five environments in Ethiopia for grain yield, 1000 kernel weight, protein concentration, gluten strength, mixing time, mixing height, colour and yellow berry to identify desirable traits for breeding purposes. Gluten strength was measured by the sodium dodecyl sulfate (SDS) sedimentation test. An electrophoretic study of gliadin and glutenin proteins was undertaken to investigate possible associations between these proteins and gluten strength. Significant genotypic differences were observed for grain yield, 1000 kernel weight, protein content, SDS-sedimentation volume, yellowness and yellow berry. Six high molecular weight (HMW) glutenin subunits patterns were identified with the combination of null and 20 being the most common. For Glu-B1, the alleles producing protein subunits of 20 and 7+8 were the most common. Alleles producing protein subunits of 6+8 were less frequently observed. Three cultivars had pattern LMW-1 while the remaining eight cultivars had pattern LMW-2. The strongest gluten strength corresponded to the mixed subunits 7+8/6+8 and 7+8/20, followed by subunits 6+8 and 7+8. Subunit 20 was associated with the lowest gluten strength. Pattern LMW-2 was strongly associated with higher gluten strength compared to LMW-1. The effects of low molecular weight (LMW) and HMW glutenin subunits were additive. In order to develop high quality durum wheats, it would be useful to discard lines with LMW-1 and HMW glutenin subunit 20 and to combine electrophoretic analysis with the SDS-sedimentation test.