THE VERNALIZATION ON MEDICINAL AND OIL PLANTS, I : OPIUM POPPY (I) THE INFLUENCE ON ITS DEVELOPMENT AND OPIUM YIELD AT 2℃

Abstract

Two groups of opium poppy seeds (Papaver somniferum L.), vernalized at 2℃ for 20 and 10 days respectively, were seeded in conformity to the general method of culture, using as the control a non-treated one, in November 1955. 1) Vernalized plants responded well in the germination and the early growth. 2) As for the height of plants, the 20-day-treated group was tallest ; and the non-treated, lowest during the early stage of growth, but during the budding and flowering time, this order was completely reversed and was immutable until the harvesting season. 3) It is recognized that the 20-day-treated group flowered about 2 days earlier than the others, and there was practically no difference between the 10-day-treated and the non-treated groups. 4) The two experimental facts the flowering promotion observed by means of the vernalization at 2℃ and the success in flowering of non-treated seeds sown in the spring of 1956 suggest that the plant seems to pass through its vernalization phase at temperatures ranging from 2℃ to the prevailing temperature in spring. 5) The vernalization on opium poppy exerted a very noticeable influence upon the yield of opium, increasing the yield 24.0 percent in the 20-day-treated group, and 11.6 percent in the 10-day-treated one in comparison with the control.