PEG-induced osmotic stress reveals genotype-dependent drought responses in chickpea (Cicer arietinum L.)

Drought is a major abiotic constraint affecting chickpea ( Cicer arietinum L.) productivity, particularly in semi-arid environments. Rapid and reproducible screening approaches can facilitate the preliminary evaluation of genotype-dependent responses to controlled osmotic stress before more resource-intensive greenhouse and field testing. Fifteen chickpea genotypes originating from Türkiye were evaluated using an in vitro embryonic-axis culture system under polyethylene glycol (PEG 6000)-induced osmotic stress at 0%, 1.5%, and 3% (w/v). Six morphophysiological traits—plant height, number of branches, number of nodes, root length, fresh weight, and dry weight—were assessed. Genotype, PEG concentration, and their interaction were evaluated using two-way analysis of variance, while principal component analysis (PCA), hierarchical clustering, and radar plots were used as exploratory multivariate approaches. PEG concentration significantly affected plant height, number of branches, number of nodes, root length, and fresh weight, but not dry weight. Genotype significantly affected all six traits, whereas a significant genotype × PEG interaction was detected only for root length ( P = 0.016). At 3% PEG, root length decreased from 4.82 cm to 1.31 cm in Azizi, while fresh weight in Menemen declined from 0.34 g to 0.04 g. These results demonstrate substantial genotypic variation in early seedling performance under controlled PEG-induced osmotic stress. Exploratory multivariate analyses further revealed differences in multi-trait performance among genotypes under the higher PEG concentration. The evaluated chickpea genotypes showed substantial variation in early seedling responses to PEG-induced osmotic stress. Root length showed the clearest genotype-specific response to increasing PEG concentration, as indicated by the significant genotype × PEG interaction, whereas fresh weight showed a more modest overall response and dry weight was not significantly affected by PEG concentration. The embryonic-axis culture system provides a controlled preliminary platform for comparative assessment of osmotic stress responses. However, these responses should not be interpreted as direct evidence of field drought tolerance, and independent experimental replication together with greenhouse and field validation is required before genotype selection for drought tolerance.