e-mail: roncallo@cerzos-conicet.gob.ar, dmartino@bucksemillas.com.ar

Durum wheat (Triticum turgidum var durum L.) is used in Argentina mainly for dry pasta production and is an important source of micronutrients. The amount of micronutrients in pasta is directly related to the quality of the grain. Genetic biofortification of micronutrients in wheat grains is a sustainable and low-cost strategy to improve nutritional status in the population.

The study of the genetic basis associated with variation in micronutrient content in wheat grains using biotechnology tools, such as association mapping methodology, can contribute to increase their concentration in grains and products. The objectives of this work were to analyze i) the genetic variability for the content of iron (Fe), zinc (Zn), manganese (Mn), and copper (Cu) in grains of two durum wheat collections; ii) to identify associated SNP markers using an association mapping strategy. Micronutrient content (mg/kg) was analyzed in whole wheat flour samples using a plasma spectrometer with atomic mass detector.

Samples were taken from the CERZOS collection (CRZ) and the Global Durum Panel (GDPv1), using 170 and 140 genotypes respectively, in three field trials (Cabildo 2014, Barrow 2017 [CRZ] and La Dulce 2021 [GDPv1]). The CRZ panel was analyzed using a 35K SNP microarray (Affymetrix) and the GDPv1 panel using a 90K microarray (Illumina). Marker-trait associations (MTA) were obtained in TASSEL 5.0 software using GLM and MLM (PCA+K) models.

A high phenotypic variability was found for the four micronutrients analyzed, but the observed range was greater in the CRZ panel. A significant negative correlation was observed between Zn content and grain yield, using the data available in the CRZ panel. Marker-trait associations were identified on all chromosomes. In particular, common regions affecting both panels were identified in 4B for Zn content (two regions linked between 65-98 Mb), in 5B associated with Fe and Zn (550-560 Mb) and in 7B affecting the content of Fe and Zn (679-684 Mb).

One genomic region was strongly associated with Mn content in 6BS (15-17 Mb) and two epistatic regions were identified for Cu content in 7A (RAC875_c35270_234 x Kukri_c9728_1171). SNP markers have been selected to validate them in four segregating F2 populations using KASP technology.