Effect of Row Spacing and Nitrogen Application Rate on Yield and Some Morphological and Physiological Characteristics of Quinoa

To investigate the effects of row spacing and nitrogen application rate on growth and yield of quinoa, a split plot experiment has been conducted in a randomized complete block design with three replications in Sabzevar during 2018. The studied factors include row spacing at three levels (25, 50, and 75 cm) and nitrogen application rate at four levels (0, 50, 100, and 150 kg N ha-1). Results show that the highest content of photosynthetic pigments, panicle length, number of seeds per plant, and biological yield belong to 150 kg N ha-1 treatment. However, the 100 kg N ha-1 treatment has had the highest number of panicles per plant (19.24) and 1000-seed weight (3.51 g). More row spacing has resulted in more chlorophyll contents, plant height, number of panicles, panicle length, and number of seeds per plant, but less 1000-seed weight, seed yield, and biological yield. The decrease in seed yield by increasing the row spacing to 50 and 75 cm has been 18.62 and 50.14%, respectively. The highest seed yield (6644.5 kg ha-1) has been produced via application of 150 kg N ha-1 at a row spacing of 25 cm. With increasing row spacing, nitrogen requirement to produce maximum seed yield declines. Thus, the highest seed yield in 75, 50, and 25 cm rows spacing are produced with the application of 50, 100, and 150 kg N ha-1, respectively. According to the results, the application of 150 kg N ha-1 and row spacing of 25 cm is recommended for planting quinoa, Sajama genotype.