Heat Stress Impact on Yield and Composition of Quinoa Straw under Mediterranean Field Conditions

Abstract

Quinoa (Chenopodium quinoa Willd.) is receiving increasing attention globally due to the high nutritional value of its seeds, and the ability of this crop to cope with stress. In the current climate change scenario, valorization of crop byproducts is required to support a climate-smart agriculture. Furthermore, research works characterizing and evaluating quinoa stems and their putative uses are scarce. In this work, straw yield and composition, and the relative feed value of five quinoa varieties, were analyzed in two consecutive years (2017–2018) under field conditions in Southwestern Europe. High temperatures were recorded during the 2017 growing season resulting in significantly decreased straw yield and improved feed value, associated with compositional changes under elevated temperatures. Crude protein, ash, phosphorus, and calcium contents were higher under high temperatures, whereas fiber contents decreased. The relative feed value was also higher in 2017 and differed among varieties. Differences among varieties were also found in straw yield, and contents of phosphorus, potassium, and calcium. Overall, the results presented here support a sustainable quinoa productive system by encouraging straw valorization and shedding light on the mechanisms underlying heat-stress responses in this crop.

Changes in Quinoa Seed Fatty Acid Profile Under Heat Stress Field Conditions

“…Protein, mineral, and fiber contents were determined as described in previous studies ( 29 , 33 ). Fat content was analyzed according to AOAC Official Methods 930.09 ( 44 ).…”

“…However, these newly bred varieties are not always well adapted to the elevated temperatures that are frequent in the Mediterranean areas, resulting in important yield penalties. In this regard, variations in the chemical composition of quinoa seeds have also been reported under heat stress field conditions ( 29 , 33 ). These include changes in the fatty acid profile of quinoa, which was shown to be affected by the environmental conditions ( 9 ).…”

“…In fact, it was introduced in northern European countries (i.e., England, Denmark, and Netherlands) in the late 1970s and early 1980s, and nowadays, it is also cultivated in the Mediterranean region ( 28 ). In Spain, quinoa has spread significantly in recent years, particularly in the southern part of the country ( 29 ).…”

Production Efficiency and Total Protein Yield in Quinoa Grown under Water Stress

“…The low seed yield observed in the 2014/2015 season may be related to high temperature (average temperature of 30.2 • C) and solar radiation during the reproductive development of quinoa in the experiment (maximum PAR of 1218.5 µmol m −2 s −1 ). In this regard, the result could be attributed to heat events around anthesis, even if they are of short duration, causes a drastic reduction in seed yield in cool-season cereals [66][67][68], and in biomass yield in quinoa [69,70], and not a decrease of the photosynthetic capacity of the leaf by photoinhibition effect [48][49][50]57,70]. In addition, a higher air temperature promotes the closure of stomata and an increase in abscisic acid (ABA) concentration, especially in conditions of water restriction, which promotes rapid crop development, reducing the accumulation of dry matter in the seeds and the seed yield [57].…”

Heat stress changes mineral nutrient concentrations inChenopodium quinoaseed

“…(Sehgal et al, 2018 ; Soares et al, 2019 ). In quinoa, temperature affects the nutrient composition of both straw (Matías, Cruz, & Reguera, 2021 ) and seed (Matías, Rodríguez, et al, 2021 ). Quinoa seeds have higher protein and fiber content and lower fat (Matías, Rodríguez, et al, 2021 ) and carbohydrate (Matías, Rodríguez, et al, 2021 ; Vrancheva et al, 2019 ) content with cultivation at higher temperatures.…”