Drought tolerance of Five Quinoa (Chenopodium quinoa Willd.) Genotypes and Its Association with Other Traits under Moderate and Severe Drought Stress

There are genotypic differences in drought tolerance (DT) among quinoa (Chenopodium quinoa) cultivars, and most of the known mechanisms of drought tolerance are encountered in this species. The objectives of the present investigation were to identify the most drought tolerant quinoa genotypes, to estimate the superiority of tolerant (T) over sensitive (S) genotypes and to identify the trait(s) of strongest association with DT. Five quinoa genotypes were evaluated in two seasons using a split plot design with five replications under three irrigation regimes, i.e. well watering (WW), water stress (WS) and severe water stress (SWS), achieving a field capacity of 95, 65 and 35%, respectively. The highest drought tolerance index (DTI) under WS and SWS was exhibited by the genotype CICA-17. Seed yield/ha (SYPH) of drought tolerant (T) genotypes was greater than the sensitive (S) ones by 31.8 and 43.6%, respectively under WS and SWS. Superiority of drought tolerant (T) over sensitive (S) quinoa genotypes in SYPH under SWS was due to its superiority in seed yield/plant and its components, water use efficiency, branches/plant, chlorophyll concentration index and leaf area. All studied inflorescence traits (inflorescence weight, diameter and length, 1000-seed weight, inflorescences/plant) were strongly inter-correlated and strongly correlated with DTI. They could be regarded as selection criteria helping plant breeder in selection programs for high drought tolerance if the heritability and genetic advance from selection for these traits are high.