The global expansion of quinoa (Chenopodium quinoa Willd.) cultivation has been related to the nutritional properties of its seeds and the ability of this crop to cope with stress. However, research works evaluating the agronomic impact of quinoa cultivation out of the Andean region are still limited, especially under Mediterranean field conditions. In this work, the agronomic performance, seed composition and nutrient uptake (NU) of five quinoa varieties were analysed in two consecutive years (2017)(2018) under field conditions in Southwestern Europe. High temperatures were recorded during 2017 growing season, resulting in significantly lower yields (1.6 t/ha) compared to 2018 (2.5 t/ha). High-temperature stress coincided with flowering stage in those medium-to-long cycle varieties and was well correlated with detrimental effects on the vegetative stage of short and medium cycle varieties. Seed composition and mineral content of quinoa varied among varieties subjected to heat stress, which could be due to differences in the stress response. Protein and fibre contents were higher under high temperatures, while fats and carbohydrates contents decreased.Nutrient uptake, utilisation and partitioning were reduced under heat stress, probably due to heat-protection mechanisms and associated biochemical changes. Early maturing varieties showed better adaptation, especially Marisma, which achieved the highest yield in both years (3.0 t/ha, on average). Overall, the results here presented support to the potential of quinoa cultivation in Europe highlighting the necessity to further explore varieties better adapted to elevated temperatures, a common stress affecting the Mediterranean area.

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.

Rice straw remains almost unutilised in the majority of cases and is usually burned. Data on rice residue production under European conditions are extremely limited. A detailed assessment of rice biomass yield, partitioning and straw collection was carried out in Spain. Eleven commercial rice varieties were evaluated in 2015, and two baling trials were performed in 2014 and 2015. The average straw yield was 9.7 t·ha−1. Straw yield, biomass partitioning indices and fibre composition varied significantly according to rice variety. Straw to grain ratio and harvest index were 1.00 and 0.50 on average for rough grain, and 1.25 and 0.41 for husked grain. Biomass partitioning indices significantly correlated with grain yield. Mean content of cellulose, hemicellulose, lignin and ash of rice straw was 32.5%, 19.8%, 6.5% and 13.7%, respectively. Straw amount of less than 3.0 t·ha−1 can be collected during the baling trials. Rice straw could represent an eco-friendly source of lignocellulosic biomass in Europe, however, in order to achieve this, baling machine improvements and special crop management should be carried out.

The nutritional quality of quinoa is often related to the high protein content of their seeds. However, and despite not being an oilseed crop, the oil composition of quinoa seeds is remarkable due to its profile, which shows a high proportion of polyunsaturated fatty acids (PUFAs), particularly in essential fatty acids such as linoleic (ω-6) and α-linolenic (ω-3). In line with this, this study aimed at evaluating the effect of elevated temperatures on the oil composition of different quinoa cultivars grown in the field in two consecutive years (i.e., 2017 and 2018). In 2017, heat stress episodes resulted in a reduced oil content and lower quality linked to decreased ratios of oleic acid:linoleic acid, larger omega-6 (ω-6) to omega-3 (ω-3) ratios, and lower monounsaturated fatty acid (MUFA) and higher PUFA contents. Furthermore, the correlations found between mineral nutrients such as phosphorous (P) and the contents of oleic and linoleic acids emphasize the possibility of optimizing oil quality by controlling fertilization. Overall, the results presented in this study show how the environmental and genetic factors and their interaction may impact oil quality in quinoa seeds.

Exploiting the relationship between the nutritional properties of seeds and the genetic background constitutes an essential analysis, which contributes to broadening our knowledge regarding the control of the nutritional quality of seeds or any other edible plant structure. This is an important aspect when aiming at improving the nutritional characteristics of crops, including those of Chenopodium quinoa Willd. (quinoa), which has the potential to contribute to food security worldwide. Previous works have already described changes in the nutritional properties of quinoa seeds due to the influence of the environment, the genotype, or their interaction. However, there is an important limitation in the analyses carried out, including the outcomes that can be translated into agronomical practices and their effect on seed quality. In the present study, several seed nutritional-related parameters were analyzed in 15 quinoa cultivars grown in a particular environmental context. Important agronomical and nutritional differences were found among cultivars, such as variations in mineral or protein contents and seed viability. More importantly, our analyses revealed key correlations between seed quality-related traits in some cultivars, including those that relate yield and antioxidants or yield and the germination rate. These results highlight the importance of considering the genotypic variation in quinoa when selecting improved quinoa varieties with the best nutritional characteristics for new cultivation environments.