A novel source of resistance to verticillium wilt in alfalfa

Verticillium wilt (VW) can cause substantial losses in yield and stand longevity in alfalfa. Resistant cultivars are available, but susceptible cultivars continue to be grown on the Canadian Prairies, where VW generally occurs only under irrigation. A study was conducted to assess the yield and persistence of 11 alfalfa lines under irrigation on three commercial fields in southern Saskatchewan. An epidemic of verticillium wilt developed at one site; the disease reaction of the susceptible Medicago sativa ssp. falcata line 'SC Mf3713' was similar to that of the resistant cv. Barrier. SC Mf3713 may carry a novel form of field resistance to VW, and merits further study.