Abstract

GONZALEZ, G.A. et al. Validación del gen de resistencia a “escaldadura” Rrs2 en los cultivares de cebada cervecera con mayor difusión en Argentina. RIA. Rev. investig. agropecu. [online]. 2020, vol.46, n.1, pp.81-87. ISSN 1669-2314.

”Scald” is an important disease in barley cultivation. In the literature, genes responsible for resistance (Rrs) have been described, which are present in barley cultivars. In Argentina, more than 70% of the area planted with barley corresponds to the Shakira and Andreia varieties. Shakira carries resistance alleles for the Rrs2 gene which can be identified by molecular techniques; however there are no reports of the response of these materials in agricultural production areas of barley in Argentina. The objective of this work was to validate the Rrs2 gene as a carrier of resistance alleles for “scald” in the most widespread varieties of barley in Argentina and to determine if the molecular marker developed on said gene can be applied in assisted selection in breeding programs. For this purpose, we used a biparental population RIL of 158 individuals derived from Andreia and Shakira. The materials were phenotypically characterized to field in the localities of Bordenave, Balcarce and Coronel Suárez. In addition, they were characterized molecularly by the presence (Rrs2 +) or absence (Rrs2-) of resistance alleles. The results show that the parents Shakira and Andreia present highly contrasting responses in the three evaluation environments. The lines showed different responses to the pathogen, it was observed that there are no significant differences between the lines carrying the resistance allele (Rrs2 +) and the Shakira variety, not were significant differences found when analyzing the response of the lines carrying the allele susceptibility (Rrs2-) and the variety Andreia. However, both groups of lines differ significantly from each other, in the same way that the varieties used as parental do. Both, the Shakira variety and the Rrs2 + lines showed good response to the disease, indicating that the allele would be responsible for the resistance to the pathogen for these materials. In contrast, Andreia and Rrs2- lines showed high presence of symptoms, indicating that these materials lack effective resistance genes for this disease. In addition, the molecular marker developed on the Rrs2 gene was shown to be effective in selecting lines derived from the crossing of both materials, indicating that this marker could be used in breeding programs that use genetic backgrounds derived from the Andreia and Shakira varieties for the selection of individuals carrying alleles of resistance to the disease. Finally, this work represents the first phenotypic and molecular approximation of brewing barley materials widely used in agricultural production systems in the main agroecological zones of Argentina.

Keywords : Malting barley; Rhynchosporium secalis; Rrs2; Moleculars markers..