Designing Novel Strategies for Improving Old Legumes: An Overview from Common Vetch

Common vetch (Vicia sativa L.) is a grain legume used in animal feeding, rich in protein content, fatty acid, and mineral composition that makes for a very adequate component to enrich feedstuff. In addition, relevant pharmacological properties have been reported in humans. The common vetch, similar to other legumes, can fix atmospheric nitrogen, a crucial feature for sustainable agricultural systems. These properties enhance the use of vetch as a cover crop and its sowing in intercropping systems. Moreover, several studies have recently pointed out the potential of vetch in the phytoremediation of contaminated soils. These characteristics make vetch a relevant crop, which different potential improvements target. Varieties with different yields, flowering times, shattering resistance, nutritional composition, rhizobacteria associations, drought tolerance, nitrogen fixation capacity, and other agronomic-relevant traits have been identified when different vetch accessions are compared. Recently, the analysis of genomic and transcriptomic data has allowed the development of different molecular markers to be used for assisted breeding purposes, promoting crop improvement. Here, we review the potential of using the variability of V. sativa genetic resources and new biotechnological and molecular tools for selecting varieties with improved traits to be used in sustainable agriculture systems.

Common Vetch, Valuable Germplasm for Resilient Agriculture: Genetic Characterization and Spanish Core Collection Development

Common vetch (Vicia sativa L.) is a legume used for animal feed because of its high protein content and great capacity for nitrogen fixation, making this crop relevant in sustainable agriculture. The Spanish vetch collection, conserved at the Spanish Plant Genetic Resources Center (CRF), is one of the largest collections of this species worldwide, including landraces, wild relatives mainly collected in Spain, and commercial cultivars, but also accessions of international origin. The analysis of the genetic diversity of this material, whose genome has not been sequenced yet, and the assembly of a representative collection could play a pivotal role in conserving and exploiting these genetic resources in breeding programs mainly in those focused on consequences and demands of climate change. In this work, a set of 14 simple sequence repeat (SSR) reference alleles for genetic diversity analysis of the CRF vetch collection has been developed, used for genotyping more than 545 common vetch accessions from all over the world and validated. All the tested markers were polymorphic for the analyzed accessions. Overall, at least 86 different loci were identified with 2-11 alleles per locus with an average of 6.1 alleles per locus. Also, the analyses of the generated SSR database support that most of these SSR markers are transferable across closely related species of Vicia genus. Analysis of molecular variance revealed that wild relatives have a higher genetic diversity than landraces. However, cultivars have similar diversity than landraces, indicating that genetic variability has been barely lost due to the breeding of this legume. Low differences of genetic variations between Spanish and non-Spanish accessions have been observed, suggesting a high degree of diversity within Spanish genotypes, which provide 95% of the total genetic variation, so we have focused our efforts on characterizing genotypes of Spanish origin that were further studied using storage protein profiles. Based on SSR, seed protein profiles, and agromorphological and passport data, a vetch core collection (VCC) containing 47 V. sativa accessions of Spanish origin has been established. In this collection, the characterization has been expanded using ISSR markers, and it has been reevaluated with new agromorphological data, including drought tolerance characters. This VCC presents a minimum loss of genetic diversity concerning the total collection and constitutes an invaluable material that can be used in future breeding programs for direct use in a resilient agricultural system.