Changes in bread-making quality attributes of bread wheat varieties cultivated in Spain during the 20th century

Abstract

Genetic gains in quality traits were assessed in grain samples from 4 field experiments involving 16 bread wheat varieties representative of those most widely cultivated in Spain during the 20th century. The allelic composition at three glutenin loci (Glu-A1, Glu-B1, and Glu-D1) was obtained by PCR-based DNA markers and published references. From 1930 to 2000 grain protein content decreased by −0.030% y−1, or in relative terms by −0.21% y−1, but the protein produced per hectare increased by 0.39% y−1. Alveographic tests revealed significant changes in dough rheological properties. Dough strength (W) and tenacity (P) increased at relative rates of 1.38% y−1 and 0.99% y−1, respectively, while dough extensibility (L) decreased by −0.46% y−1, resulting in an increase of 1.45% y−1in dough equilibrium (P/L). The rise in protein quality could be related to the replacement of the null allele by subunits 1 or 2* at Glu-A1 and the prevalence of subunits 7 + 8 and 5 + 10 at Glu-B1 and Glu-D1 loci, respectively, in the most recent varieties. Dough extensibility was affected by water input during the crop cycle, this relationship being partially explained by the presence of the 5 + 10 HMW glutenin subunit. Fermentation tolerance was improved in the most modern varieties. Collapse during fermentation was avoided only in doughs with a W ≥ 159 J × 10−4 and a P/L ≥ 0.56 mm H2O mm−1, levels achieved by most of the modern varieties. The over-strong and unbalanced rheological properties of some modern varieties resulted in highly porous doughs, and no clear advances in dough maximum height during fermentation were attained.

This study was partially funded by the Spanish National Institute for Agriculture and Food Research and Technology (INIA) [RTA2004-058-C04 and RTA2009-061-C03] and Spain’s Inter-Ministerial Commission for Science and Technology (CICYT) [AGL-2009-11187]. The Centre UdL-IRTA is part of the Centre CONSOLIDER INGENIO 2010 on Agrigenomics funded by the Spanish Ministry of Education and Science. M. Sanchez-Garcia was a recipient of a PhD grant from INIA.