Comparison of methods for the assessment of gluten strength in durum wheat for pasta making

CONTI V; MIRAVALLES M; CERVIGNI G D L; MANTHEY F; POLCI P; MIRANDA R; DUBCOVSKY J; ECHENIQUE V

Mar del Plata, Buenos Aires

Congreso; 7th International Congress of Wheat; 2005

Durum wheat is grown mainly for pasta production. The nutritional value of the finished product is dependent of the total amount of protein and their composition, that also influence gluten strength. This is an important factor for pasta making and a central selection criteria in cultivar development. The aim of this work was to evaluate the accuracy (screening value) of the currently used methods  for the assessment of gluten strength in durum wheat. Ninety four recombinant imbreed lines (RILs) -originated by a cross between a strong gluten variety (Kofa)  and a high yielding experimental line of weak gluten type (UC1113)- were evaluated. Over two consecutive harvest seasons two quantitative (grain protein and wet gluten content) and four qualitative (gluten index, SDS volume, cooked pasta firmness and mixograph score) parameters were compared for gluten strength assessment. In both years, either protein or gluten content showed highly significant correlation (p<0.01) with gluten index (negative) and cooked pasta firmness (positive), while no significant correlations (p>0.2) were observed between quantitative parameters and SDS sedimentation volume or mixograph score. These results suggest a less environmental influence over the qualitative parameters gluten index and cooked pasta firmess, being a more direct effect of the genotype. Based in these data and because of simplicity of the method, SDS was preferred for the evaluation of the same RILs in a third growth environment. Mean SDS volumnes for Kofa and UC1113 were 55.67 and 38.83 mm, respectively. The correspondent values in the progeny were between 32.33 and 65.33 mm, with an average SDS value of 42.38 mm. HPLC (high performance liquid romatography) was also used in order to investigate protein composition (glutenin to gliadin ratio and proportion of insoluble to total polymeric glutenins) in the cross parents. The overall result of our study suggest a consistent higher glu/gli ratio and a higher proportion of insoluble to total polymeric glutenins for the cultivar Kofa. We are now advocated to map QTLs for glutenins and gliadins quantified by HPLC. Molecular markers flanking the QTL for both types of proteins, together with the SDS test, will be used upon selection of genotypes with higher gluten strength in a durum wheat breeding program.