Advanced breeding for virus resistance in plants
Résumé
Breeding for virus resistance was successful in the past years using conventional breeding methods since many virus resistant cultivars have been delivered for a wide range of crops. Genome mapping provided molecular markers for many resistance loci (i.e., major genes or Quantitative Trait Loci) that were introgressed into cultivars e.g., through backcross breeding schemes. Molecular mapping also delivered much information on the genomic architecture of polygenic and quantitative resistances. However, marker assisted selection for such complex traits is difficult so that the combination of quantitative resistance factors from multiallelic origins commonly relies on sophisticated phenotyping procedures. The cloning of resistance genes and the rapid development of high throughput molecular technologies increased the access to functional markers and multiallelic markers, promoting the applicability of marker assisted selection for complex traits at the whole genome scale in the near future. In parallel, the advances in the identification of molecular determinants of plant/virus interactions and in genetics and evolution of virus populations provide new selection criteria for breeders to choose the most durable resistance genes and gene combinations, so that breeding for durable virus resistance becomes an accessible quest