(238) Ethylene Screening using 1-aminocyclopropane-1-carboxylic acid (ACC) in Both Nonmutagenized and Mutagenized Snapdragon Lines

Abstract

A tissue culture screen for ethylene tolerance using 1-aminocyclo-propane-1-carboxylic acid (ACC) was optimized for a snapdragon (Antirrhinum majus) inbred line, OAK564. Two experiments were conducted using various concentrations of ACC (ranging from 0 to 100 μM). Presence of 5 μM ACC in the tissue culture medium elucidated biological activity in snapdragon seeds. This screen was used to determine relative sensitivity to ethylene in 48 hybrid lines. Different levels of sensitivity to ethylene were observed among the various hybrid lines. Moreover, 40,000 mutagenized seeds from three M2 populations, derived from different levels of EMS (0.5%, 0.75%, and 1.0%) treatments, were screened for ethylene sensitivity. A total of 231 putative mutants were recovered spanning eight distinct phenotypes based on the `triple response' assay. Of these putative mutants, 16 mutants were selected for further analysis, including at least one and up to three lines from each of the eight phenotypic classes. Plants were established in the greenhouse, and allowed to grow to maturity to collect selfed seeds. These seeds were once again screened with 5 μM ACC to determine the level of ethylene sensitivity present within each of the eight phenotypic classes. Responses in the M3 populations varied from complete ethylene tolerance to ethylene sensitivity. Implications of these results on the recovery of ethylene tolerant mutants will be discussed.