Can Mediterranean durum wheat landraces contribute to improved grain quality attributes in modern cultivars?

Abstract

The variability for quality attributes existing in a collection of 154 durum landraces from 20 Mediterranean countries and 18 modern cultivars was determined with the ultimate goal of identifying potential quality-enhancing genotypes for use in breeding programs. Field experiments were conducted during 3 years under rainfed conditions in northeastern Spain. Environmental effects were the most important in determining protein content, grain yield and yellow color index of the endosperm (grain flour), and the least important in determining EU quality index (QI), gluten strength and grain filling rate. QI is a weighed composite index determined from protein content, gluten strength, yellow color index and thousand kernel weight. Multivariate analysis detected four groups; three including landraces and one comprising modern cultivars. Landraces from the eastern Mediterranean countries had the highest mean QI and the widest variability for individual quality traits, but were characterized by relatively small grains. Landraces from the western Mediterranean countries had greater grain filling rates and heavier grains. Protein content, gluten strength and yellow color index were similar between eastern and western groups. The low QI and reduced variability characterizing the landrace group from the north Balkan Peninsula support the hypothesis of a different origin for this group. Modern cultivars, as a group, were the most productive and showed high QI, but they had the lowest grain protein content and phenotypic variability. Landraces that could be used as sources of quality-improving attributes and/or those that could be used in breeding programs without substantial quality handicaps were identified from different groups. Landraces can be particularly useful in breeding programs to improve gluten strength, grain weight and accelerate grain filling rate.

Durum wheat (Triticum durum Desf.) Mediterranean landraces as sources of variability for allelic combinations at Glu-1/Glu-3 loci affecting gluten strength and pasta cooking quality

“…18 and the null allele at Glu-A3, Glu-B3 and Glu-B2 loci, respectively, was present in the Egyptian LR identified in the USDA gene bank as 'PI-366109', which reached the highest SDS-sedimentation test value of all the genotypes included in this study (11.7 ml). This LR had been previously reported to have very high EU quality index, protein content and sedimentation index (Nazco et al 2012). It is important to note that this particular genotype had 1 of the 54 combinations (41 % of the total 131 combinations) with a non-null allele at Glu-A1 but was one of the very few with a significantly enhanced strength.…”

“…18 ? 19 and the null allele at Glu-A3, Glu-B3 and Glu-B2 loci, respectively) was identified in the French LR 'Trigo Glutinoso' (PI-174699), which was reported in a previous study as having high EU quality index and a high sedimentation index calculated as the quotient between gluten strength and protein content (Nazco et al 2012). A second combination (number 123), formed by bands 2* and 7 ?…”

“…Nazco et al (2012) reported large variability for yield and quality traits in the same set of LR used here, which were useful to separate three major geographical regions within the Mediterranean Basin (West, East and North Balkan) with contrasting qualitative and productive characteristics. The same study concluded that the Eastern Mediterranean LR retained the greatest variability, which is consistent with this region being the geographic center of genetic diversity for wheat (Feldman 2001).…”

“…LR were selected-from a larger collection of 231 accessions-on the basis of their genetic variability determined by 33 SSR-markers (Nazco et al 2012). Seeds provided by public gene banks (Centro de Recursos Fitogenéticos INIA-Spain, ICARDA Germplasm Bank, and USDA Germplasm Bank) were increased in bulk and purified by eliminating off types.…”

“…Plots were mechanically harvested at commercial maturity. Experimental details may be found in Nazco et al (2012).…”