Effects of drought stress and field treatments on seed germination and early growth traits of parental berseem clover seeds

Improving seed resistance to water shortage can enhance forage production and sustainability in arid and semi-arid agricultural lands. This three-year field, laboratory and greenhouse study proposes applying surfactant to effectively prevent the detrimental impacts of severe drought conditionson early plant development. Seeds retrieved from six parental plantsof berseem clover (Trifolium alexandrinum L.) developedunder I100 (100% irrigation water)/I100+s (irrigation water plus surfactant), I75/I75+s and I50/I50+s treatments in the field. In a germination experiment, drought stress was imposed through seven osmotic potentials (0, -0.2, -0.4, -0.6, -0.8, -1, and -1.2 MPa) created by using polyethylene glycol (PEG-6000). Comparative analyses evaluated the interaction between field treatments effects by drought stress and surfactant application on seed germination and early growth stage of berseem clover seedlings. Seeds developed in the field from moderately limited irrigation with surfactant (I75+s) attained a favorable seed germination percentage (78%) under a drought stress of -0.4 MPawhich acheived24.3% increase in germination percentage compared tocontrol (I100) without surfactant). Surfactant application across all fieldirrigation treatments hada constructive effect on the weighted germination index compared to counterpart treatments. Under -0.4 MPadrought stress + surfactant at gemination project, the highest seedling height (10.2 cm) was obtained from the seeds retrieved fromI75 and I50 field treatments. Seeds retrieved from I75+shada better performance under drought stress with the highest seedling height of 11.2 cm from irrigation water+surfactant. These results support the idea that adding surfactant to irrigation water can support the agricultural sustainability in arid and semi-arid regions.