Effects of Sowing Date on Some Agronomic Characteristics and Alkaloid Content of Datura Stramonium in Semi-Arid Conditions

Alkaloids of diferent plant, including many Solanaceae species, constitute important natural sources for variety of pharmaceutical products. The amounts of various secondary plant products are strongly dependent on the growing conditions and agronomical applications such as planting date, fertilization, irrigation etc. The aim of this was to study the effects of sowing date on some agronomic characteristics and total alkaloid content of thorn apple (Datura stramonium), investigated in the environmental conditions from Dicle University, Agricultural Faculty, Field Crops Department experimental area, during 2010 and 2011 growing years. In the research, plant height, stem diameter, number of branches per plant, number of capsule per plant, capsule width, capsule length, 1000-seed weight, fresh herb yield, herba yield, seed yield and total alkaloid content were examined. At the end of the study, in the trial of thorn apple with sowing dates, according to two years mean, seed yield, fresh herb yield, dry herb yield and total alkaloid yield were changed between 335 kg ha−1 and 704 kg ha−1, 5933 and 20537 kg ha−1, 1613 kg ha−1 and 4800 kg ha−1, and 0.270% and 0.391%, respectively. The effect of sowing date was found significant on the investigated characteristics, when sowing delayed, agronomic characteristics were also decreased. The highest values related with seed yield, fresh and dry herbage of thorn apple were obtained sowing of 01 Apr. Moreover, thorn apple plant showed morphogenetic variation when compared leaf and seed alkaloid contents.