Bayesian and Frequentist Association Mapping for Sclerotinia Head Rot Resistance in Sunflower

FILIPPI CV; ZUBRZYCKI J; DI RIENZO JA; AGUIRRE N; QUIROZ F; RIVAS G; PUEBLA AF; CORDES D; MORENO MV; FUSARI CM; MARINGOLO C; ALVAREZ D; HEINZ RA; HOPP E; PANIEGO NB; LIA VV

Foz de Iguazu

Congreso; 11th International Congress of Plant Molecular Biology; 2015

SAG

Argentina has a long tradition of sunflower breeding, and its germplasm is a valuable genetic resource worldwide. In our country, the sunflower production is addressing a significant gap between actual and potential sunflower yield, mainly due to biotic and abiotic stresses. With the aim to characterize new resistance sources for disease resistance, we conducted an association mapping study to identify gene loci involved in resistance to Sclerotinia Head Rot disease, one of the most devastating diseases in sunflower growing areas.Association mapping (AM) is a method for QTL mapping that has a potential resolution to the level of individual genes. Our study is based on an association mapping population (AMP) composed of 135 sunfower inbred lines from the INTA breeding program. The AMP was genotyped with an Illumina 384-plex SNP oligo pool assay, 31 candidate genes and 42 microsatellite markers (SSR). The AMP was phenotypically evaluated for disease incidence, severity and incubation period after assisted inoculation with the pathogen across five campaigns in replicated field trials.Mixed linear models accounting for population structure and kinship relatedness, as well as a Bayesian approach for multilocus association mapping, were used for the statistical analysis of phenotype-genotype associations, allowing the identification of 13 polymorphisms associated with disease reduction (p