Effects of maturity and plant spacing on the morphine content of two varieties of Papaver somniferum L.

Two varieties of opium poppy were grown under irrigation for one season and their capsules analysed for morphine content by gas chromatography. Harvest of the capsules at 29-33 days after flowering (mature seed) gave 6.70 kg/ha morphine as compared to 5.36 kg/ha morphine in capsules harvested at 4-6 days after flowering. With constant row spacing (30 cm between double rows on ridges 102 cm apart), a plant spacing of 6 cm gave 20 per cent more morphine than either 12- or 18-cm spacing. There was no statistical difference in morphine content between a blue- and a white-seeded variety.