Integrating Phenotypic and Genetic Diversity for Verticillium Wilt Resistance Breeding in Sunflower.

MONTECCHIA, JUAN F.; FILIPPI, C.V.; FASS, MÓNICA I.; MARINGOLO, C.A.; CERRUDO, I; DOMINGUEZ, M. ; HOPP, H.E.; ESCANDE, A.; GONZALEZ, J.; DI RIENZO, JULIO; ALVAREZ, D.; QUIROZ, F.; LIA, V. V.; PANIEGO, N.B.; HEINZ, R.A.

Congreso; XXVI Plant and Animal Genome; 2018

Fungal diseases represent a significant constraint for sunflower grain and oil yield production worldwide. One preponderant disease affecting sunflower crop is Verticillium Wilt (SVW), which is caused by the soil-borne fungal pathogen Verticillium dahliae (Kleb.). In Argentina, SVM is endemic and affects an area of 1.2 million hectares, where 70% of the sunflower crop is grown. Fungicide control is not effective against SVW. Thus, resistance breeding is a key strategy to cope with this affection.In this work, we explore the genetic diversity and the phenotypic response against SVW of 164 inbred lines from an association mapping population (AMP) as the first step for a Genome-Wide Association Study (GWAS) approach to assist breeding for disease resistance. The main goals of this work were (a) to evaluate the response of the AMP to SVW by multivariate analysis, and (b) to assess the relationship between resistance response and genetic structure.The phenotypic responses to SVW were evaluated in the AMP inbred lines during three consecutive seasons. Disease incidence, severity, intensity and AUDPC adjusted means were obtained using Generalized Linear Mixed Models. In parallel, the population sub-structure, and genetic diversity were estimated using a 18161 SNP-imputed loci matrix.Principal Component Analysis was conducted on the inbred´s phenotypic means for each variable scored, partitioning the data by different criteria (i.e., country of origin) to establish their relationship with the distribution of phenotypic variation.Through this study we have found resistance sources across the AMP sub-structuring groups, supporting the implementation of GWAS to assist breeding on SVW-resistance.