In the 1930s the stem nematode, Ditylenchw dipsaci was causing heavy losses in alfalfa stands, particularly in the Antelope Valley area of Los Angeles County. Again, material from Turkistan was found to have some plants which were resistant, and a new variety named Lahontan was developed and released. Subsequently it was found that an introduction from Iran with less winter dormancy had plants with a high level of stem nematode resistance, and this variety is being used in breeding work at Davis.