Growth, Development, and Thebaine Content of Papaver bracteatum Lindl. in Relation to Spacing1

Abstract

AbstractPapaver bracteatum Lindl. is being investigated as an alternate source of the alkaloid thebaine, an industrial precursor of codeine and other analgesics. The effects of 0.15‐, 0.30‐, and 0.60‐m spacing on the growth, development, and thebaine content of P. bracteatum were investigated in the field on an Elkton silt loam (clayey, mixed, mesic Typic Ochraquult). The experiment was conducted for 2 yr at Beltsville, MD, using germplasm from the UNB‐4 collection from Iran. All treatments were replicated five times. Intraspecific competition greatly reduced plant growth and development at the 0.15‐m spacing, and, as a result, the number of flowering plants was reduced 75% in the second year relative to the first year. Second‐year increases were noted in capsule number and dry weight yield for both the 0.30‐ and 0.60‐m spacings, with the most capsules per plant for the 0.60‐m spacing. However, yield of phytomass per hectare was 130% greater for the 0.30‐m spacing than for the 0.60‐m spacing. Thebaine production per hectare for the duration of this investigation was highest for the 0.30‐m‐spacing treatments and lowest for the 0.15‐m treatment. Optimum spacing of P. bracteatum plants may be a function of the time plants are permitted to grow.