GENOME WIDE ASSOCIATION STUDY FOR DISEASE RESISTANCE AS A SUSTAINABLE APPROACH FOR MAIZE PRODUCTION

RUIZ M.; PELLEGRINO C.; RAMONDA G.; GUILLERMO L.; BALZARINI M.G.; BONAMICO N.C.; ROSSI E.A.

San Juan

Jornada; XLI Reunión Anual de la Sociedad de Biología de Cuyo; 2023

Sociedad de Biología de Cuyo

Maize (Zea mays L.), one of the most important crops worldwide, is affected by foliar diseases that limit its global production. Among the most relevant are Mal de Río Cuarto (MRC) caused by Mal de Río Cuarto virus and Bacterial leaf streak (BLS) caused by Xanthomonas vasicola pv. vasculorum (Xvv). MRC is a viral disease that causes yield losses and is endemic in the area, while BLS has increased in Argentina during recent years causing a cosmetic damage and yield loss in the susceptible genotypes. The aim of this work was to identify genomic regions associated with resistance to MRC and BLS to improve maize breeding programs. A diverse panel of 172 maize lines developed and provided by the International Maize and Wheat Improvement Center was evaluated for resistance to MRC and BLS in four environments of central Argentina in 2019, 2020, 2021 and 2022. In all environments the natural infestation caused an incidence of 85%. For each genotype, incidence and severity (SEV) of symptomatology, measured as the mean rating of all plants in the plot, were measured. The predictor of the SEV genetic merit that does not include environmental effects and 46990 single-nucleotide polymorphisms obtained by genotyping-by-sequencing were used in the genome-wide association study (GWAS). The GWAS allowed us to identify six genomic regions associated with MRC in five chromosomes and seven genomic regions associated with BLS in six chromosomes. No significant genetic correlation was observed between the response to both diseases. These genomic regions can be incorporated to improve maize breeding programs as a sustainable approach for maize production.