Genotype-dependent responses to long-term water stress in Chenopodium quinoa Willd

Abstract

Within the current climate context, freshwater resources have become scarce. Agriculture, especially in rain-fed conditions, should deal with the need for increasing yields to contribute to food security under limiting water availability. Exploring underutilized crops such as Chenopodium quinoa (quinoa) has become a unique opportunity as some of these crops possess the ability to tolerate several abiotic stresses, including drought. In line with this, this work aimed at evaluating the genotype-dependent response to drought by comparing the performance of different European-adapted cultivars (F14, F15, F16, and Titicaca). The results show that the cultivars here evaluated presented different mechanisms to cope with long-term water stress, including changes in phenology, morphology, or physiology. Among them, the cultivar F16 might be the most promising genotype to grow under water-limiting conditions as it was able to increase Water Use Efficiency (WUE), reducing the stomatal conductance and keeping CO₂ assimilation rates similar to well-watered conditions, maintaining seed yield and increasing harvest index (HI) under water deficit conditions. Furthermore, based on these results, we propose a model in which differences between a tolerant and a sensitive genotype are presented. Altogether, we believe that this work will significantly contribute to broadening our understanding regarding how quinoa responds to long-term water stress highlighting genotype-related differences that will allow the selection of the best adapted genotypes for water-limiting environments.