Picloram-induced plant regeneration from maize shoot segment

Regeneration-competent cultures of mazie have been established not from immature embryos but from rather recalcitrant seedling segments after induction on picloram-containing Murashige-Skoog (MS) media. Eleven-day old seedling shoots of S-type cytoplasmic male sterile line of the W64A inbred were sliced into 2mm sections and placed on MS media containing 10 uM picloram in the dark for 30 days. This was followed by 16 hours of light per day. After two weeks, regeneration-competent tissue was identified, isolated, and then was either maintained on the initial media for more than ten months, or induced to produce plantlets on media containing no auxin. Concentrations of picloram in the media greater than 100 uM produced embryo-like structures incapable of regenerating plants. Picloram was more potent than 2,4-D for inducing embryo-like structures. Regenerated plants have produced either female or male-female combination inflorescenes and viable seeds when pollinated. The second generation produced both male sterile and male fertile, phenotypically normal plants.