Resistance against orobanche crenata in bitter vetch (Vicia ervilia) germplasm based on reduced induction of orobanche germination

Bitter vetch (Vicia ervilia (L.) Willd.) is a legume well adapted to cultivation in marginal areas, being an important source of protein for animal feed in low input cropping systems. Sur- prisingly, it is an underutilized crop as it could be a good alternative to increase the sustainability of extensive rainfed cropping systems. In Mediterranean rainfed cropping systems, the productiv- ity of bitter vetch is severely reduced by the parasitic weed species Orobanche crenata (Forsk). To date, few resistant bitter vetch genotypes have been identified. O. crenata infection process initiates with the recognition of germination factors exuded by roots of susceptible hosts. In this work, the interaction of a collection of bitter vetch accessions and O. crenata has been analyzed in order to discover accessions with low germination induction activity. Through a combination of field and rhizotron experiments, two bitter vetch accessions were selected showing low germination-induction activity, which resulted in less infection. In addition, in vitro germination assays revealed that the low germination activity was due to low exudation of germination factors and not due to the exudation of germination inhibitors. The selected low germination-inducers genotypes could be the basis for a new breeding program generating locally adapted alternatives with resistance to O. crenata.

Financial support is acknowledged in relation to S.N., C.I.G.-V., and E.M.C. from the European Agricultural Fund for Rural Development (FEADER)-Andalusia Operational Program 2014–2020 PR.CRF201900.002 and to M.F.-A. from the research projects RYC-2015-18961 and AGL2017-87693-R of the Spanish Ministry of Science and Innovation (co-funded with EU FEDER Funds).