THE EFFECTS OF PLANT DENSITY AND IRRIGATION ON THE LODGING, YIELD AND YIELD COMPONENTS OF POPPIES (PAPAVER SOMNIFERUM L.)

Irrigation had a major effect on poppy yield. Applied until flowering (128 mm), it resulted in a 26% increase over the dryland erect head yield while irrigation through to 50% leaf senescence (256 mm) resulted in a erect head yield increase of 90% over the dryland yield. Dryland poppies had a greater tendency to lodge than irrigated poppies and the lodged heads were smaller than upright heads.

There was an asymptotic relationship between density and total head yield. In this season, wind was above average and the incidence of lodging increased significantly at densities above 50/m2 (3% at 25/m²; 30% at 100/m2). Consequently there was a parabolic relationship between erect head yield and density with the maximum at 30/m². Density had no effect on capsule morphine content, so that the erect morphine yield related directly to the erect head yield. The maximum erect morphine yield was obtained at about 50/m2 although 95% of the maximum was achieved at densities between 20–100/m2.

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