Photosynthetic activity is a fundamental process in the physiology of plants, and its regulation plays an important role in determining the effect of abiotic factors. Quinoa is a plant species of agronomic and nutritional interest that has been recognized for its adaptability to extreme environmental conditions, however, climate change may result in unfavorable conditions capable of affecting the natural development of this species, which is of great interest culture and research in South America. To evaluate the response of quinoa to stress, techniques could be used that quantify the loss of light energy through its dissipation in the form of heat. However, the measurement of chlorophyll fluorescence is the most widely used and accessible technique for field research, which allows to recognize the relationships between the plant and agroclimatic factors. This review summarizes the physiological effects of heat, radiation, salinity, and nutrient and water availability, as well as their possible interactions on quinoa.

The great diversity of quinoa allows variations in physiological, production, and compositional performance. This study aimed to evaluate six quinoa cultivars through the physiological and nutritional responses of their seeds. Different dynamics were identified in the plant height, and the number of leaves was adjusted to sigmoidal models with R2 greater than 0.97 and 0.77, respectively. The chlorophyll concentration varied through the phenological phases, as did the maximum quantum yield of photosystem II. Differences in the quinoa grains were found between CIEL*a*b* colorimetric coordinates and protein, carbohydrate, and fat contents. In this sense, quinoa cultivars manifest different biological behaviors associated with their genetic nature. Besides, a relationship between cultivars and seed composition was recognized. These results will allow researchers to study other significant differences between the precocity expressed by the Puno, Nariño, and Titicaca cultivars and those with a longer phenological cycle such as the Soracá cultivar.