Mapping of quantitative trait loci controlling Orobanche foetida Poir. resistance in faba bean (Vicia faba L.)

Abstract

Although in the Mediterranean region the most important Orobanche weed attacking leguminous crop is Orobanche crenata, recently Orobanche foetida has been found attacking faba bean, vetch and
chickpea in Tunisia and vetch in Morocco. In this study we have identified and map the quantitative trait loci (QTL) controlling resistance to O. foetida in faba bean (Vicia faba) and studied their stability in two different environments. One hundred and forty four Recombinant Inbred Lines (RILs) derived from the cross between a susceptible and a resistant parent were analysed using isozymes, RAPD, seed protein genes, STSs, ESTs, microsatellites and SCAR markers. Two hundred and seventy seven markers segregating in the RIL population could be mapped into 21 linkage groups, 9 of them assigned to specific chromosomes. By evaluating broomrape resistance in these RILs under field conditions, two QTLs for O. foetida resistance were identified showing instability across environments. Whereas Of1
was located in the chromosome 1 and explained 7% of the phenotypic variation in one environment, Of2 was assigned to chromosome 3, was only identified in the second environment and explained 9% of the
trait variation. Since this map has been used before to locate O. crenata resistance QTLs its exploitation offers the possibility of accumulating resistance genes in V. faba germplasm against both parasites.