Safflower (carthamus tinctorius l.) oil content and yield components as affected by co-inoculation with azotobacter chroococcum and glomus intraradices at various N and P levels in a dry climate

Abstract

With respect to the significance of medicinal plants, testing methods, which may enhance their performance, can be important agriculturally and economically as well as from healthy points of view. Hence, grain oil content and yield components of the medicinal plant, safflower (Carthamus tinctorius L., cultivar IL-111), were evaluated in a field experiment. Treatments including co-inoculation with Azotobacter chroococcum and the Arbuscular mycorrhizal (AM) fungi Glomus intraradices at different rates of nitrogen (N) and phosphorous (P) fertilization including F0: control, F1: N50 + P25, F2 = N100 + P50, and F3 = N150 + P75 kg ha#−1 were tested. The experiment was conducted in the spring of 2006 as a factorial on the basis of a completely randomized block design in three replicates. Grain oil content and yield components were determined. A. chroococcum increased plant N content. The two- (fungi and fertilization) and three-way (bacteria, fungi, and fertilization) interactions significantly affected grain oil content and weight of 1,000 grain, respectively. While chemical fertilization significantly decreased oil percentage, the bacterium and the fungus significantly increased oil percentage. However, for the oil content the combination of microbes with chemical fertilization resulted in the highest oil content. The effective co-inoculation of safflower with A. chroococcum and G. intraradices by increasing oil content and yield components suggests the effectiveness of this biological method for safflower production as well as a favorite partial replacement for N and P fertilization. The effects of biological fertilization on the enhancement of seed nutritional values may be more pronounced than chemical fertilization.