jg.vazquez.garcia@upm.es

Triticum turgidum L. spp durum is a cereal crop mainly grown in the Mediterranean basin. Among durum wheat quality related traits, the grain protein content, and the yellow color of the semolina and pasta products are the most valued by breeders and consumers. In the present study we focused on semolina color. A bi-parental HIFs (Heterogeneous Inbred Families) population was characterized for the yellow color of the semolina during two crop seasons (2019/20 and 2020/21).

This population was developed from two ancient durum wheat cultivars: Endural released by Benoist in 1989, with good rheological properties; and Aldura, an Italian landrace that presents good semolina color. One-hundred seven HIFs were evaluated for the Yellow Pigment Content (YPC) and the Yellow Pigment Loss (YPL) after exposure to oxygen and light. With these two parameters it was possible to determine the percentage loss of the yellow pigment (% of loss) in semolina samples.

Besides, the population was genotyped for two pasta color-related genes which were polymorphic in the parental lines, Psy-A1 and Lpx-B1.1. Psy-A1 is related to the initial carotenoid content for which Endural and Aldura carried the alleles Psy-A1a and Psy-A1I, respectively. The Lpx-B1 gene encodes a lipoxygenase which affects the carotenoids and consequentely the yellow color of the pasta at post-cooking stages.

For that gene, Endural carries the Lpx-B1.1c allele carrying a deletion associated with a 4.5 reduction in lipoxygenase activity. Statistical analyses revealed that the lines carrying the Psy-A1I allele presented a higher yellow pigment content compared to the lines carrying the Psy-A1a allele. On the other hand, lines which did not carry the deletion for Lpx-B1.1 presented a lower YPL and a higher percentage loss compared to lines with the Lpx-B1.1c allele.

No epistatic effects between both genes were detected, as it was observed that differences lines with higher YPC and carrying the allele Psy-A1l were maintained after cooking even when the fully functional allele, Lpx-B1.1a, was present.

Finally, a fixed effect model confirmed that the best allele for pasta color was Psy-A1l combined with Lpx-B1.1c allele.

The characterization of these materials polymorphic for one carotenoid synthesis related gene (Psy-A1) and for one carotenoid degradation related gene (Lpx-B1.1) through molecular markers facilitates the study of the effect of each allele in the carotenoid synthesis and in the final color of the pasta products and while aid MAS in wheat breeding programs.

Acknowledgments

This research Project has been funded by the Comunidad de Madrid through the call Research Grants for Young Investigators from Universidad Politécnica de Madrid (project MEJOR-TRIGO) and by projects PID2019-109089RB-C32 and PID2021-122530OB-I00 from Ministerio de Ciencia e Innovación, Spain. JGV is inanced by Juan de la Cierva grant from Ministerio de Ciencia en Inovación, NB is financed by an excellence grant from the government of Argelia. VGM is financed through a FPI scholarship correspondant to for the PID2021-122530OB-I00 of the State Research Agency (Ministry of Science and Innovation)