Evaluation of cucumber (Cucumis sativus L.) genotypes for drought toleranceusing high throughput PEG induced drought indices

Cucumber is highly sensitive to drought due to its high-water requirement. Identifying genotypes that can tolerate early-stage moisture stress can reduce mortality and improve survival during drought. In this study, 16 genotypes were evaluated for seedling stage drought stress (SDS) tolerance using PEG8000 (18%). Five traits namely germination percentage, germination index, germination energy, shoot length (85.26% reduction) and root length were recorded and analyzed using five selection indices, namely arithmetic mean productivity (AMP), geometric mean productivity (GMP), harmonic mean productivity (HMP), stress tolerance index (STI) and membership function value (MFV). The indices were applied to assess the variability among genotypes and identify those tolerant to drought stress. Among the indices MFV and AMP were determined to be most desirable due to the better discriminating ability and strong correlation with mean shoot length. Based on the indices, the genotypes G9, G2 and W4 were identified as the most tolerant to PEG induced drought stress at seedling stage. Thus, the identified genotypes can be used in further breeding program of cucumber improvement.