title: Variability in glutenin subunit composition of Mediterranean durum wheat germplasm and its relationship with gluten strength.
abstract: The allelic composition at five glutenin loci was assessed by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1D SDS-PAGE) on a set of 155 landraces (from 21 Mediterranean countries) and 18 representative modern varieties. Gluten strength was determined by SDS-sedimentation on samples grown under rainfed conditions during 3 years in north-eastern Spain. One hundred and fourteen alleles/banding patterns were identified (25 atGlu-1and 89 atGlu-2/Glu-3loci); 0·85 of them were in landraces at very low frequency and 0·72 were unreported. Genetic diversity index was 0·71 for landraces and 0·38 for modern varieties. All modern varieties exhibited medium to strong gluten type with none of their 13 banding patterns having a significant effect on gluten-strength type. Ten banding patterns significantly affected gluten strength in landraces. AllelesGlu-B1e(band 20),Glu-A3a(band 6),Glu-A3d(bands 6 + 11),Glu-B3a(bands 2 + 4+15 + 19) andGlu-B2a(band 12) significantly increased the SDS-value, and their effects were associated with their frequency. Two alleles,Glu-A3b(band 5) andGlu-B2b(null), significantly reduced gluten strength, but only the effect of the latter locus could be associated with its frequency. Only three rare banding patterns affected gluten strength significantly:Glu-B1a(band 7), found in six landraces, had a negative effect, whereas banding patterns 2 + 4+14 + 15 + 18 and 2 + 4+15 + 18 + 19 atGlu-B3had a positive effect. Landraces with outstanding gluten strength were more frequent in eastern than in western Mediterranean countries. The geographical pattern displayed from the frequencies ofGlu-A1cis discussed.
authors.affiliation: IRTA (Institute for Food and Agricultural Research and Technology) , Field Crops Section, Rovira Roure, 191, E-25198 Lleida , Spain.
authors.forename: R
authors.initials: R
authors.lastname: Nazco
authors.affiliation: CIMMYT (International Maize and Wheat Improvement Center) , 06600 México, DF , México.
authors.forename: R J
authors.initials: RJ
authors.lastname: Peña
authors.affiliation: CIMMYT (International Maize and Wheat Improvement Center) , 06600 México, DF , México.
authors.forename: K
authors.initials: K
authors.lastname: Ammar
authors.affiliation: IRTA (Institute for Food and Agricultural Research and Technology) , Field Crops Section, Rovira Roure, 191, E-25198 Lleida , Spain.
authors.forename: D
authors.initials: D
authors.lastname: Villegas
authors.affiliation: CIMMYT (International Maize and Wheat Improvement Center) , 06600 México, DF , México.
authors.forename: J
authors.initials: J
authors.lastname: Crossa
authors.affiliation: Department of Soil and Crop Sciences , Colorado State University , Fort Collins, CO 80523 , USA.
authors.forename: M
authors.initials: M
authors.lastname: Moragues
authors.affiliation: IRTA (Institute for Food and Agricultural Research and Technology) , Field Crops Section, Rovira Roure, 191, E-25198 Lleida , Spain.
authors.forename: C
authors.initials: C
authors.lastname: Royo