Effect of salinity on seed germination of Vigna marina a wild relative of crop Vigna species using hydrotime modelling

Vigna marina (Fabaceae) is a wild relative of cultivated Vigna species. Crop wild relatives are important genetic source, which can be utilized in developing desired crop varieties. V. marina is a vine, growing naturally in sandy seashore with high saline soil conditions and have the different threshold water potential effects on germination pattern rather non-salt tolerant Vigna species. Thus, salinity tolerant traits of V. marina can be utilized to develop salinity tolerant crop Vigna varietiesThe objective of the study was to study the salinity stress tolerance of V. marina seeds during germination using a hydrotime model. Healthy seeds of V. marina were extracted from randomly selected plants from coastal area of Southern Province of Sri Lanka. Germination and imbibitions of untreated and chemically scarified seeds were studied. Several acid scarification treatments were conducted to determine the best dormancy breaking treatment. Acid scarified seeds of V. marina and V. radiata were separately germinated in series of salt concentrations to develop a hydrotime model.Chemically scarified seeds of V. marina increased mass > 62% while, untreated seeds increased mass <21%. Chemically scarified seeds germinated 100% whereas, untreated seeds germinated 67% both at light and dark conditions. Results revealed that 5% of V. marina seeds have physical dormancy. Chemically scarified seeds for 5 minutes showed the highest germination which was > 85% and confirmed that chemical scarification for 5 minutes was the best dormancy breaking treatment. In Na2SO4 base water potential is [ψ b(60%)] -5.47 MPa and – 5.43 MPa for V. marina and V. radiate respectively. In KNO3 base water potentials are – 5.65 MPa and – 5.59 MPa for V. marina and V. radiata respectively. Lower base water potentials of V. marina seeds compared to base water potential of V. radiata indicate the salt tolerance ability of V. marina than the V. radiata. Therefore V. marina can be utilized to develop salt tolerant crop Vigna specie