The influence of sowing and planting seedlings at different dates in autumn on the yield and quality of the opium poppy (Papaver somniferum L.)

Abstract

Turkey is the world’s leading country in legal poppy cultivation and morphine production. As with other producing countries, the poppy is traditionally cultivated in Turkey through the sowing of seeds during the autumn. However, if the seasonal rains are insufficient and irregular, this can lead to problems with germination and emergence. In this research, the option of solving these problems by using seedlings in production, instead of seeds, was investigated. The study compares the yield and quality performance of the two production methods, planting seedlings and direct seed sowing in the poppy cultivar ‘Ofis-4’. Field experiments were conducted on three sowing/planting dates, namely October fifteenth, November first, and November fifteenth, during the growing seasons of 2017/18 and 2018/19 in the semi-arid ecological conditions of the southwestern region of Turkey. The plants produced by seedling transplantation and by sowing were compared in terms of the yields of seeds and capsules along with yield-related traits and the contents of seed-fixed oil and capsule opium alkaloids. The planting seedling method was seen to be an average of one week faster than the sowing method. In terms of the sowing/planting time delays in the autumn season, it was also observed that the ripening difference between both propagation methods started to narrow. If the general averages are considered, the highest capsule and seed yields were obtained from planting seedling on October fifteenth, the first planting date, in both years. Since the planting dates were late, the capsule and seed yield decreased while it was found that the contents of capsule alkaloids, except morphine and codeine, were not significantly affected by the production method and sowing/planting dates. On the other hand, the direct sowing method and first sowing date produced the highest morphine (0.53 and 0.58 %, respectively) and codeine (0.101 and 0.126 %, respectively) contents. It was therefore concluded that the seedling planting method can be recommended as an alternative to the direct sowing method traditionally applied in poppy production for the achieving of high capsule and seed yields.