Thebaine variations between germplasm sources within one collection of Papaver bracteatum Lindl.

Plants of Papaver bracteatum Lindl. derived from different germplasm sources within one Iranian collection were grown for 18 and 37 weeks in the greenhouse and controlled environment chambers. Gas-chromatographic analyses showed significant differences between thebaine concentrations of root tissue for 18-week-old plants, but not for 37-week-old plants. The two age groups did not differ in thebaine yield per unit of dry weight of root tissue. However, due to more profuse root growth, the total yield of thebaine from roots of the older plants was about four times that of the younger plants. Shoot thebaine concentrations differed significantly for 18- and 37-week-old plants. The over-all mean thebaine concentration for shoots of older plants was nearly twice that of younger plants. The variation in thebaine concentrations in these plants suggested genetic differences between the germplasm sources. Thus, domestication of P. bracteatum will require selection of germplasm from within and between collections, for plants of the greatest economic potential.