The effect of hydro- and halo-priming on the morphophysiological performance and enzyme activities of common bean (Phaseolus vulgaris L.) under greenhouse conditions

Seed priming can improve crop performance, but cultivar-specific responses of common bean ( Phaseolus vulgaris L.) to different priming methods remain insufficiently characterized. This study evaluated the effects of calcium sulphate (CaSO 4 ) halo-priming and distilled-water (DH 2 O) hydro-priming on morphophysiological traits and antioxidant enzyme activities in five common bean cultivars (RS 5, Tygerberg, RS 6, PAN 148, and DBS 830) under controlled greenhouse conditions. Both priming treatments significantly improved plant height, stem diameter, leaf number, chlorophyll content, stomatal conductance, transpiration rate, and net photosynthetic rate compared with unprimed controls ( p < 0.05), although responses varied among cultivars and treatments. CaSO 4 generally produced superior morphophysiological performance, with DBS 830 and Tygerberg showing strong responses. Antioxidant activities were concentration- and cultivar-dependent. CaSO 4 -primed Tygerberg showed a 72.5% increase in superoxide dismutase (SOD) activity at 250 µg mL –1 , while CaSO 4 -primed PAN 148 exhibited a 49.62% increase in catalase (CAT) activity at 7.81 µg mL –1 relative to the unprimed control. Three-way ANOVA indicated significant effects of cultivar, priming treatment, concentration, and their interactions on SOD and CAT activities ( p < 0.05). Correlation analyses revealed concentration-dependent associations between antioxidant and morphophysiological traits. A composite performance index identified 500 µg mL –1 as the concentration providing the highest integrated SOD and CAT performance. Overall, CaSO 4 priming enhanced morphophysiological performance and modulated antioxidant activity in a cultivar- and concentration-dependent manner. Further validation under field conditions and diverse agroecological environments is recommended.