Abstract

In order to study the effect of plant density on phenology and oil yield of safflower herb under irrigated and rainfed planting systems, an experiment was conducted in Agriculture Research Station of Islamic Azad University, Ardabil Branch, Ardabil, Iran in 2010 as a factorial experiment based on a randomized complete block design with four replications. The factors included planting system (irrigation and rainfed) and plant density (60, 50, 40 and 30 plants.m^-2). The results showed that the density of 30 plants.m^-2 under both planting systems and the density of 40 plants.m^-2 under rainfed system had the highest number of days to 50% emergence. The densities of 60 and 50 plants.m^-2 under rainfed system had the highest number of days to 50% branch-bearing. The density of 60 plants.m^-2 under irrigated system had the lowest number of days to 50% bud-bearing. The plants at the densities of 60 and 50 plants.m^-2 under rainfed system initiated flowering earlier than other treatments. The density of 50 platns.m^-2 was ranked in the same group with the densities of 40 and 60 plants.m^-2 and irrigated system. under irrigated system, the highest oil percentage was obtained from the lowest density and the lowest one from the density of 40 plants.m^-2 and the densities of 50 and 60 plants.m^-2 were ranked in the same group, while under rainfed system, the highest oil yield was obtained from the highest density under irrigated system and the lowest one from the densities of 40 and 60 plants.m^-2 under rainfed system. As shown, oil percentage was increased with the decrease in density. The significantly highest seed yield was produced at the density of 60 plants.m^-2 under rainfed system which was ranked in the same group with the density of 50 plants.m^-2 under irrigated system.

Key words: Flowering time, emergence, oil percentage, safflower, yield, yield components.