Non-Peer ReviewedYellow pigment is an important quality trait in durum wheat (Triticum turgidum L. var durum). Few genes within the pathway responsible for carotenoid biosynthesis have yet to been identified in durum wheat. Zeta-carotene desaturase (ZDS) is an enzyme involved in carotenoid biosynthesis, and variation in the gene(s) coding for ZDS may partially explain the variation observed in endosperm color among durum wheat cultivars. For this study, a PCR strategy was used to clone and sequence greater than 1200 bp of the Zds genes from durum cultivars Kofa (high pigment) and W9262-D063 (medium pigment). Comparison of partial nucleotide sequences indicated the presence of four Zds genes which we temporarily designated as tdZds1, tdZds2, tdZds3, and tdZds4. Since durum wheat is a tetraploid, the presence of four genes suggests that the Zds gene may in fact be duplicated in the durum wheat genome, with two sets of homeologous genes. However, we have only obtained single clones of Zds2 and Zds4 from each of the two parents, and these results will need to be confirmed. However, we are currently in the process of mapping Zds1 and Zds3 to determine their role in the expression of yellow pigment concentration in durum wheat
