Patent ID: 8212117

Claim:
A method of identifying a lettuce plant that is resistant to Russet Spotting and/or Yellowing, comprising growing etiolated lettuce seedlings from a population of plants under an ethylene containing atmosphere, selecting seedlings showing reduced ethylene sensitivity as compared to the starting population by identifying seedlings having hypocotyl elongation as compared to growth in an atmosphere of air without ethylene, and screening the seedlings showing reduced ethylene sensitivity for resistance against Russet Spotting and/or Yellowing, wherein identifying seedlings having hypocotyl elongation as compared to growth in an atmosphere of air without ethylene comprises a) selecting a seedling having elongated hypocotyls or roots as compared to a seedling of a control plant; b) self-fertilizing the selected seedling to produce seeds; c) germinating a portion of the seeds in darkness and in the presence of ethylene to produce S1 seedlings and germinating a portion of the seeds in darkness and in air to produce S2 seedlings; and d) comparing hypocotyls of S1 seedlings to hypocotyls of S2 seedlings and to hypocotyls of control plant seedlings; wherein the seedlings are ethylene-insensitive if the hypocotyls of S1 seedlings are elongated as compared to hypocotyls of S2 seedlings and control plant seedlings.