GROWTH AND DEVELOPMENT OF OPIUM POPPY (PAPAVER SOMNIFERUM L.) AS A FUNCTION OF TEMPERATURE

The U. S. State Dept. annually estimates yields of opium poppy (Papaver somniferum L.) and other narcotic crops around the world. When field sampling is possible, objective methods are used to estimate yields. However, field sampling is expensive and can be dangerous so other techniques are being sought. One method is to simulate crop performance using a computer model. To develop such a model, crop response to soil conditions, weather, and management practices must be understood. The first step in this process is to examine the influence of individual factors by growing the crop in controlled environments, keeping all factors except one at optimum levels, and varying that factor over a wide range. Temperature is a major weather variable. To study its effects on opium poppy, young seedlings were grown in controlled environment chambers in a 12h photoperiod at a light intensity of 1000±100μmol m^<-2> s^<-1> with day/night temperatures of 12/7℃, 16/11℃, 20/15℃, 24/19℃ and 28/23℃. Dry weights of plant parts and specific leaf area (SLA) were measured at various stages during plant development. The optimum mean temperature for poppy growth was between 16 and 20℃. Development rate was reduced at lower temperatures but remained relatively constant over the 20/15, 24/19, and 28/23℃ treatments. SLA was sensitive to temperature, maximizing at 19.5℃. Variation in SLA could explain some of the differences in relative growth rate and growth rate associated with temperature. Gum yield could be estimated from capsule dry weight or capsule volume using a linear regression model (r^2=0.71 and 0.75 respectively). Analyses of these data represent an important first step in quantifying the effects of temperature on poppy growth, development, and gum yield