The effect of irrigation on the growth and yield components of poppies (Papaver somniferum L.)

Abstract

SummaryThe effects of four irrigation treatments on the growth and yield of poppies were studied in two ‘drought’ seasons in Tasmania. Irrigation increased total dry-matter production, leaf area index and delayed leaf senescence in both seasons. Irrigation, which continued until leaf senescence, increased total morphine yield by 5–20 kg/ha compared with no irrigation. This yield increase was attributed to the increase in the number and yield of lateral heads, the yield of terminal heads and capsule morphine concentration.As the effects of irrigation on head yield reflect the effects on total dry-matter production, irrigation guidelines for poppies were developed from an analysis of plant growth during theseason. For maximum yield, one irrigation of 50 mm should be applied at the 50% hook stage, at 50% flowering, at the end of flowering and 2 weeks after the end of flowering. Growers who currently cease irrigation at 50% flowering can expect yield increases of 4–13 kg/ha ifthey apply two further irrigations thereafter.