Quinoa ( Chenopodium quinoa ) Root System Development as Affected By Phosphorus and Zinc Sulfate Application in an Alkaline Soil

Responses of quinoa root characters are unknown while using different nutritional elements either in soil or foliar application, especially in alkaline soils. This research has been conducted in a controlled condition with a set of pot experiments to study the root responses of three cultivars of quinoa (Giza 1, Q26, Titicaca) as influenced by the various amount of triple superphosphate fertilizer (0, 6, 12, 18 mg/kg soil) and zinc sulfate foliar application (0, 4 and 8 g/l). Results showed that 18 mg/kg triple superphosphate produced the highest root dry weight (1.27 g/plant), number of root branches (218), root volume (2.06 cm 3 ), and specific root weight (SRW) (46.39 mg/cm). The highest value of root surface belonged to the Q26 cultivar, and Giza 1, respectively. Regarding the three-fold interaction, the maximum values of root traits and grain production were found in the Q26 cultivar by using 18 mg/kg triple superphosphate and foliar application at the rate of 4 g/l zinc sulfate. The optimal combination of P and Zn nutrients improved the N, P, K accumulation in quinoa grain, especially in the Q26 cultivar, and nutrient content changes in Giza 1 and Titicaca cultivars were lower between control and optimal levels. It was concluded that better performance was achieved when optimal amounts of macro/microelements have been used with selecting cultivars with a wider root system and higher potential for nutrient uptake in alkaline soils.