Impact of Seed Maturation and Drought on Seed Germination and Early Seedling Growth in White Clover (Trifolium repens L.)

Abstract

Background: Understanding the drought tolerance of white clover seeds during germination and early seedling growth and how that is linked to seed maturation in legume species, is crucial to developing new stand establishments.Methods: An experiment was conducted in Randomized Block design in two factorial concept to explore how seed maturation and drought tolerance influence seed germination and early seedling growth using the two factors: seed coat color (yellow and brown, two levels as one factor) and drought intensity (control: 0 MPa [distilled water], mild drought: -0.2 MPa, moderate drought: -0.4 MPa and severe drought: -0.6 MPa, four levels as another factor).Result: In contrast to the yellow-coated seeds, the mean germination percentage, germination index, seedling vigour index and radicle length of the brown-coated seeds were lowered by 7.9%, 23.1%, 20.5% and 12.9%, respectively. Compared to the control, introducing drought conditions reduced the mean of germination percentage, germination index, seedling vigour index and radicle length of yellow-coated seeds by 52.4%, 64.1%, 41.9% and 23.2%, respectively. Meanwhile, drought affected brown-coated seeds more than yellow-coated seeds. The results indicating that the seed quality of white clover seed lots with yellow-colored coats higher than the seed lots with brown-coloured coats. In agronomic practice, a larger proportion of yellow-coated seeds should be harvested to improve new stands successful establishment under environment easy to dry.