ABSTRACT
Combined effect of water and sulfur deficit on the productivity and antioxidant capacity of quinoa in pots

Margarita Ocampo1, Susana Fischer2*, and Inés Figueroa2
 
The challenge of feeding the world’s population implies producing a greater quantity and better quality of food. Therefore, a deeper knowledge of the adaptation capacity of crops to different edaphoclimatic environments is required to face the challenges of climate change. The objective was to evaluate the effect of water and S availability on agronomic characteristics, yield, total phenol content and antioxidant capacity in quinoa (Chenopodium quinoa Willd.) ‘Regalona’. The test was out in outdoor pots in the 2019-2020 and 2020-2021 seasons. The substrate was silt loam soil. The design was a two-factor split block, S availability (SA) with 8, 12 and 20 mg kg-1 S, and water availability (WA) 25%, 50% and 100% in the grain filling stage. Likewise, there was no interaction (p > 0.05) between WA×SA for the agronomic and productive characteristics. However, the lowest WA (25%) decreased (p ≤ 0.05) yield and height of the plant, while the highest S fertilization increased (p ≤ 0.05) plant height, panicle length, thousand seed weight and yield. In antioxidants, 100% and 25% WA generated differences (p ≤ 0.05) in total phenols (TPC) and flavonoids content (TFC). Treatment SA exerted differences (p ≤ 0.05) between 8 and 20 mg kg-1 in the TPC and ferric ion reducing antioxidant power (FRAP) tests. WA×SA generated differences (p ≤ 0.05) in the TFC and the oxygen radical absorbance capacity (ORAC) in the 2020-2021 season. At 12 mg kg-1 SA, the highest TFC was with 25% WA and in ORAC it was at 100% WA. The degree of correlation between TPC and antioxidant activity by the FRAP method, coefficients of 0.76 and 0.66 were found for the 2019-2020 and 2020-2021 seasons, respectively.
Keywords: Chenopodium quinoa, sulfur-water interaction, phenolic compounds, water availability.
1Universidad de Concepción, Facultad de Ingeniería Agrícola, Chillán, Chile.
2Universidad de Concepción, Facultad de Agronomía, Chillán, Chile.
*Corresponding author (sfischer@udec.cl)