Evaluation of atrazine resistance in protoplast regenerants of Solanum nigrum L.

Mesophyll protoplasts of atrazine-resistant and atrazine-susceptible biotypes of Solanum Nigrum were cultured in the presence or in the absence of atrazine. Proliferation occurred in all the cultures, but only the resistant biotypes grew and regenerated plants. To eveluate atrazine resistance, a chlorophyll fluorescence decay index (Relative Decay Initial Rate) was calculated. Distributions of RDIR values are clearly different and it is possible to discriminate between resistant and susceptible plants. Regenerants obtained from resistant biotype culture displayed values similar to the corresponding seed-derived plants.