Abstract

Drought stress is becoming increasingly frequent and severe under climate variability, adversely affecting carrot root length, weight, and diameter. This study tested the hypothesis that drought stress differentially affects taproot traits in cultivated and wild carrot accessions originating from diverse geographical regions. The drought tolerance responses of 110 (64 cultivated and 46 wild) carrot accessions were evaluated for three years. Length, weight, and diameter of carrot roots were noted under well-watered conditions and drought stress field conditions; absolute decreases due to drought (AD), growth inhibition index (GI), relative drought tolerance (RDT), and drought tolerance index (DTI) of these three traits were also calculated. Of the 110 carrot accessions, 27 were classified as tolerant, 30 as moderately tolerant, 27 as moderately susceptible, and 26 as susceptible. Pearson’s correlation coefficient analysis revealed that root weight and diameter were positively and significantly correlated (P < 0.001; r = 0.81) under drought stress. Principal component analysis (PCA) revealed five principal components, of which the first two captured 59 percent variation. Based on the contribution percentage towards overall variation, indices of root weight and diameter were prominent in PC1 and PC2, respectively, highlighting their importance. Hence, these findings suggest that root weight is a reliable trait to be considered for future drought stress tolerance studies of carrot germplasms. This study identified drought-tolerant carrot accessions of various colors as a novel genetic resource from different geographical origins.