Patent ID: 8847020

Claim:
A method of identifying a Lactuca plant having a trait of reduced susceptibility to displaying a visible symptom of senescence that can be stimulated by ethylene and genetic information in its genome which is responsible for the reduced susceptibility trait, as compared to a control plant which is of the same variety as the plant having the reduced susceptibility trait except that the control plant is ethylene-sensitive as the control plant displays the visible symptom of senescence that can be stimulated by ethylene and does not have genetic information in its genome which is responsible for the reduced susceptibility trait, which method comprises: a) germinating a population of seeds in darkness and in the presence of ethylene to produce seedlings, wherein the concentration of ethylene is at least 10 μg/liter; b) selecting a seedling having elongated hypocotyls or roots as compared to a seedling of the control plant; c) self-fertilizing the selected seeding to produce seeds; d) 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, wherein the concentration of ethylene in step d) is about 4-5 μg/liter; and e) comparing hypocotyls of S1 seedlings to hypocotyls of S2 seedlings and to hypocotyls of control plant seedlings; wherein if the hypocotyls of S1 seedlings are elongated as compared to hypocotyls of S2 seedlings and control plant seedlings, a plant having the reduced susceptibility trait and the genetic information in its genome responsible for the reduced susceptibility trait as compared to a the control plant is identified; and, wherein the visible symptom of senescence that can be stimulated by ethylene is Russet Spotting or Yellowing.