SELECTION FOR GLUTEN STRENGTH IN 3 DURUM-WHEAT CROSSES

Strong gluten in durum (Triticum turgidum L. var durum) semolina is desirable for manufacture of pasta, so estimates of gluten strength are used as selection criteria in breeding programs. Gliadin band 45 (gli 45) is associated with high gluten strength, while band 42 (gli 42) is associated with weaker gluten. Our objective was to compare prediction of gluten strength in early generations by means of the sodium dodecyl sulphate (SDS) sedimentation test with the method using gliadin electrophoresis banding pattern. ne methods assist in elimination of undesirable lines, thereby reducing the cost of testing for yield and other traits. Three single crosses were made among four parents, one of which ('Wascana') carries the allele for gli 42, while the others carry the gli 45 allele. Spaced F2 plants were grown in the field in 1990, and F2-derived F4 lines were grown in 1991 on an Aridic Haploborall soil. Gluten strength was predicted by SDS sedimentation, and gliadin bands were identified by a monoclonal antibody (MAb) on seed from single F. plants. The SDS sedimentation test was repeated on seed harvested from F4 lines, and efficacy of the two methods was compared. Heritability of SDS sedimentation ranged from 0.57 to 0.68 for the three crosses. Elimination of F2 lines carrying gli 42 reduced the population size by up to 44%, and increased (P < 0.01) mean sedimentation of the F4 by 0.3 to 0.6 cm compared with the unselected populations. Retention of lines homozygous for glie 45 further increased (P < 0.01) F4 sedimentation, and was not different from selection for F2 sedimentation at an intensity of 20%. The MAb test is faster and less costly than the SDS-sedimentation test. We recommend the MAb test for initial screening, followed by the SDS-sedimentation test on selected F2 plants.