Allelic Variants of Glutamine Synthetase and Glutamate Synthase Genes in a Collection of Durum Wheat and Association with Grain Protein Content

Wheat is one of the most important crops grown worldwide. Despite the fact that itaccounts for only 5% of the global wheat production, durum wheat (Triticum turgidumL. subsp.durum) is a commercially important tetraploid wheat species, which originated and diversified in theMediterranean basin. In this work, the candidate gene approach has been applied in a collection ofdurum wheat genotypes; allelic variants of genes glutamine synthetase (GS2) and glutamate synthase(GOGAT) were screened and correlated with grain protein content (GPC). Natural populations andcollections of germplasms are quite suitable for this approach, as molecular polymorphisms close to alocus with evident phenotypic effects may be closely associated with their character, providing a betterphysical resolution than genetic mapping using ad hoc constituted populations. A number of allelicvariants were detected both forGS2andGOGATgenes, and regression analysis demonstrated thatsome variations are positively and significantly related to the GPC effect.Additionally, these genesmap into homoeologous chromosome groups 2 and 3, where several authors have localized importantquantitative trait loci (QTLs) for GPC. The information outlined in this work could be useful inbreeding and marker-assisted selection programs