Evaluation of USDA Lupinus sp. Collection for seed-borne potyviruses

Plant viruses pose a threat to the acquisition, maintenance and distribution of lupin germplasm (genus Lupinus, family Fabaceae). The availability of sufficient quantities of healthy and virus-free seeds from maintained lupin collections is mandatory for conducting lupin research. The objective of this research was to determine which lupin species were potentially infected with potyviruses (presumably seed-borne) upon germination in the greenhouse. The procedure for screening lupin seedlings in the greenhouse for potyviruses incorporated enzyme-linked immunosorbent assay followed by elimination or segregation of infected seedlings from the population before transplantation into the field plots for regeneration and accession characterization. None of the accessions in this evaluation had been tested previously for virus. From 2002 to 2005, 15 perennial (30 accessions) and 6 annual lupin species (213 accessions) were evaluated on site at the Western Regional Plant Introduction Station in Pullman, WA, USA. While none of the greenhouse perennial seedlings tested positive for potyvirus, seedlings in three annual species (Lupinus albus, Lupinus angustifolius and Lupinus luteus) were infected by potyviruses, presumably by seed transmission. Future testing may focus on the annual species, thus saving limited germplasm maintenance resources.