A simplified protocol for micropropagation of guayule (Parthenium argentatum Gray)

A simple, efficient protocol for in vitro micropropagation of guayule is re ported. Shoot cultures were maintained on MS (Murashige and Skoog, 1962) me dium supplemented with 1.0 mg l(-1) (4.4 mu M) 6-benzylaminopurine and 0.02 5 mg l(-1) (0.13 mu M) alpha-naphthaleneacetic acid. Excised shoots were tr eated for 14-18 h with 100 mg l(-1) (492.1 mu M) indole-3-butyric acid in 0 .5 x MS salts to induce rooting. The shoots were subsequently inserted into cellulose plugs which were packed in sterile, ventilated plastic culture v essels and moistened with 0.5 x MS medium without growth regulators. Use of cellulose plugs, liquid medium and ventilated culture vessels facilitated acclimation. Rooted shoots were transplanted into potting medium and acclim ated to greenhouse conditions by covering with a cloche for 2 d, followed b y daily watering for the first week.