[Characteristics of Papaver somniferum L. cv. ikkanshu cultivated in Izu]

The seeds of Papaver somniferum L. cv. Ikkanshu were sown in November (Autumn sowing: AS) and March (Spring sowing: SS) in a field at Izu Experimental Station for Medicinal Plants of National Institute of Health Sciencs, and both AS and SS plants were cultivated to investigate their growth, opium yield and alkaloid content in the opium. Growing periods from the sowing to the opium harvest were approximately six months for AS plants and three months for SS plants. Sizes of plants and capsules in AS were bigger than those in SS, reflecting their growth period. Opium yields per an are in AS and SS were 212.09 g and 142.03 g, respectively. The opium was able to be collected four times in the AS plants though the SS plants ceased to exude opium after the second incision. Therefore higher yield of opium in AS plants seems to be attributed to an amount of opium in the third and fourth incision. Average morphine content in the total opium was 15.61% in AS plants and 15.04% in SS plants, and the estimated amounts of morphine per an are in AS and SS plants were 33.16 g and 21.38 g, respectively.