DIFFERENTIAL RESPONSE OF Chenopodium quinoa GENOTYPES TO ORGANIC AND CHEMICAL FERTILIZER COMBINED WITH DIFFERENT N APPLICATION RATE

Knowledge about differential responses of genotypes to nitrogen (N) fertilizer source and N application rate could be an invaluable aid in quinoa improvement strategies. The objectives of the present investigation were: (i) to assess the effects of genotype and its interaction with fertilizer type and N rate on quinoa traits and (ii) to identify the potential genotypes under organic and mineral fertilizers combined with low N (LN), medium N (MN) and high N (HN) rates. A two-year field experiment was conducted, using a split split-plot design with three replications. Main plots were devoted to two fertilizer types (compost and Ammonium nitrate), sub-plots to three N rates (71.4, 142.8 and 214.2 kg N/ha), and sub sub-plots to 37 quinoa genotypes. Genotypes showed a wide range for all studied traits. Seed yield of all genotypes grown under organic fertilizer was superior to that under mineral fertilizer. The superiority of organic to mineral fertilizer in quinoa productivity was highly pronounced by ICBA-Q5 (327.27%) followed by Nat-1 (309.19%) and Sekam-Bitter (254.94%). In general, the highest yielding genotypes under organic fertilizer were different from the highest yielding genotypes under mineral fertilizer. Under HN organic fertilizer, the five highest yielding genotypes were Nat-1 (12203 kg/ha), R-103 (11679 kg/ha), ICBA-Q5 (9273 kg/ha), Sekam-Bitter (8855 kg/ha) and Sekam-Sweet (7557 kg/ha). Whereas, under HN mineral fertilizer, the five highest yielding genotypes were Agritec-Beige (3818 kg/ha), Egyptian White (3216 kg/ha), NAD-1-W (3167 kg/ha), CICA-17 (3107 kg/ha) and NAD-1-B (2875 kg/ha). The genotype Sekam-Bitter showed the shortest duration to maturity (102.2 day) under HN organic fertilizer. The genotype Rainbow recorded the highest seed protein content (17.8%) under HN organic fertilizer. These genotypes could be considered useful quinoa germplasm in future breeding programs for improving seed yield, N efficiency, seed protein content and earliness traits.