QTLs for Orobanche spp. resistance in faba bean: identification and validation across different environments

Broomrapes are holoparasitic plants which infect faba bean (Vicia faba L.), among other legumes. Here, we aimed to identify and validate quantitative trait loci (QTLs) for broomrape resistance in the cross 29H x Vf136 and to investigate the existence of common and specific genomic regions against Orobanche crenata and O. foetida. A genetic map including 171 markers was constructed for QTL analyses. Field trials for O. crenata were conducted during three consecutive seasons at Crdoba (Spain) and in a single season at Kafr El-Sheikh (Egypt). QTL analysis for O. foetida was performed using data from a single season at Beja (Tunisia). Seven QTLs for O. crenata were identified. Oc7 on chromosome VI was detected over 3 years at Crdoba, explaining between 22 and 33 % of the phenotypic variation, which make it the most promising candidate for future marker-assisted breeding for broomrape resistance in faba bean. O. crenata QTLs identified at Kafr El-Sheikh did not co-localize with those identified in Crdoba. Environmental differences together with the diversity of parasitic populations between locations may account for the discrepancy. Three QTLs for O. foetida were detected. Co-localization of Oc8 and Of3 in chromosome V confirms a common resistance against both O. crenata and O. foetida, as previously reported.