Biparental QTL and Association Mapping for Sclerotinia Head Rot Resistance in Cultivated Sunflower

ZUBRZYCKI J; FUSARI CM; MARINGOLO C; DI RIENZO, J.A.; CERVIGNI G; NISHINAKAMASU V; FILIPPI, CV; TROGLIA C; QUIROZ F; ALVAREZ D; ESCANDE A; HOPP E; HEINZ RA; LIA VV; PANIEGO NB

Mar del Plata

Congreso; 18th International Sunflower Conference; 2012

ASAGIR, ISA

ABSTRACT- Sclerotinia Head Rot (SHR) is considered one of the most damaging diseases of sunflowerworldwide, causing average yield reductions of 10 to 20%. Sunflower genotypes show large variations inresistance to SHR. Due to the multigenic nature of this trait, breeding approaches face serious limitations.The aim of this work was to present advances for biparental and association mapping (AM) ascomplementary strategies to identify both QTL and genes conferring resistance to SHR.- A total of 94 Recombinant Inbred Lines (RIL) encompassing the biparental population obtained from PAC2 (resistant genotype) X RHA266 (susceptible genotype) and an Association Mapping Population(AMP, 94 inbred lines) were evaluated for SHR during three seasons. Assisted inoculations with thefungal pathogen Sclerotinia sclerotiorum were applied. Severity, incidence and spread of the disease wereassessed by visual scoring. The RIL population was genotyped with 671 DNA markers. A total of 52candidate genes were selected and 34 resulted polymorphic in a Core Set of inbred lines selected for SNPand Indel development. Genotyping of AMP and statistical analysis is on going in the context of the AMapproach.- A total of 20 quantitative trait loci (QTL, LOD score >3) accounting for incidence (I), severity (S)and the area under the disease progress curve (AUDPC) were identified on specific regions of linkagegroup (LG) 10, 13, 14. A significant association was found between one of the evaluated candidate genehaplotypes and SHR incidence (P