INTERACTION OF NITROGEN AND PLANT DENSITY ON GROWTH AND YIELD OF TWO QUINOAS (Chenopodium quinoa Willd.) CULTIVARS IN FARS PROVINCE, IRAN

As a field crop, quinoa (Chenopodium quinoa Willd.) has great potential in improving food for humans and animals even under marginal lands. Experiments were carried out at Marvdasht, Iran, in 2017 and 2018 main crop growing season to evaluate the effect of 4 levels of nitrogen (0, 75, 150, and 225 kg. ha-1), three levels of density (20, 30, and 40 plants.m-2), and two cultivars of quinoa (Titicaca and Sajema). The factorial experiment was performed based on a randomized complete block design with three replications. The results showed that nitrogen fertilizer significantly affected all measured traits. By increasing the nitrogen and plant density, the plant height, grain yield, and biological yield increased. The highest harvest index and nitrogen use efficiency was obtained from the highest density level. In all studied traits, Titicaca cultivar had greater than Sajema. Due to the superiority of 225 kg. ha-1 of nitrogen and the density of 40 plants.m-2 in terms of grain yield, it seems that this amount of nitrogen fertilizer and planting density to achieve good yields in the test and similar areas is also recommended. Also, the higher seed yield in Titicaca cultivar than Sajema is recommended for planting in the studied areas.