Development of novel HMW-GS gene combinations within bread wheat by means of homoeologous recombination
Résumé
In an attempt to improve the breadmaking quality of wheat by elaborating novel gene combinations useful in wheat breeding programmes, homoeologous recombination between wheat homoeologs has been induced to increase copy number of interest genes. Such approach has been applied to duplicate Glu-1 locus coding for the high molecular weight glutenin subunits (HMW-GS). These endosperm proteins play an important role in the end-use quality of wheat flour which is a complex character influenced by both genetic factors and plant growth conditions. Duplication of the Glu-A1 and Glu-D1 loci have been obtained in the hexaploid wheat cv. Courtot through translocations between the long arm of both chromosomes 1A and 1D using the ph1b mutation. Amongst all the translocated lines produced, two lines duplicated respectively for the Dx2+Dy12 genes (Glu-D1) and Ax2* gene (Glu-A1) have been characterized at the proteomic, rheological and technological levels. The cumulative and interaction effects on gluten strength and mixing properties of dough associated with duplication of Glu-1 loci were assessed. The described genetic approach, performed without GMO technology, lead to novel genetic combinations aimed to broaden the natural genetic variability of wheat quality.