Abstract

Seed dormancy and germination present significant challenges when wild species are domesticated for cultivation and economic exploitation. Wild plant species are generally characterized by dormant seeds with variable germination widely spread over time. The objective of this study was to evaluate the influence of colour selection on seed germination of wild mustard (Brassicaceae) species that have been identified as wild edible leafy vegetable in South Africa. Seed lots were separated by colour and germinated in a completely randomized design (CRD) after chilling and after-ripening for 6 months. The light seed lot of cultivar Kwayimba(K) showed higher germination percentage than the dark seed lot of the same cultivar but colour selection did not improve the germination in cultivars Isaha (I) and Maslahlisane (M). The dark seed lot of K recorded the lowest germination percentage and the slowest germination rate. Chilling improved the speed of germination in wild mustards, but after-ripening had no effect. Seed colour change in wild mustards intensifies after physiological maturity and may be accompanied with weight increase or not. The seed coat colour may not be a good indication of the physiological status of the seed but together with physiological tests (germination) can give insight on the quality of a seed lot.

Key words: Seed colour, image analysis, seed germination.