IN-VITRO CULTURE SELECTION INCREASES GLYPHOSATE TOLERANCE IN BARLEY

In vitro culture of barley calluses has been used to produce plants wi th increased glyphosate tolerance. Calluses from immature embryos of b arley Hordeum vulgare L. 'Jeff') were cultured on Murashige and Skoog medium with 10(-6), 10(-5), 10(-4), 5x10(-4), 10(-3), or 10(-2)M glyph osate for one, four or thirty months. Plants were regenerated from cal luses maintained in glyphosate medium at 10(-6), 10(-5) or 10(-4)M for four months, at 10(-5) or 5x10(-4)M for one month and at 10(-5)M for thirty months. The progeny of each regenerated plant was analyzed for response to glyphosate. Some progenies showed increased tolerance to g lyphosate.