METHODS FOR INCREASING THE EFFICIENCY OF SEED-GERMINATION IN THE FODDER LEGUMES TAGASASTE AND ESCOBON (CHAMAECYTISUS-PROLIFERUS (L FIL) LINK SENSU-LATO)

The breaking of seed dormancy in the seven,morphological forms of Chamaecytisus proliferus (L. fil.) Link is reported. These seven forms had similar responses to the treatments studied and high percentage germination (> 90%) was obtained after (1) boiling in water for 6-9 min, (2) boiling in water for 3 or 6 min followed by immersion in concentrated sulphuric acid for 6 or 3 min respectively, (3) immersion in concentrated sulphuric acid for 3 or 6 min followed by boiling in water for 3 or 6 min respectively and (4) culture of excised embryos. Manual scarification of the and region also gave high germination percentages but cotyledons were shed from many of the seedlings which died shortly after radicle emergence. Seeds treated with concentrated sulphuric acid for 10-20 min had low germination percentages ( < 20%) although this treatment gave rise to some differences between the forms endemic to the island of La Palma (i.e. white tagasaste and typical tagasaste) and the other morphological types. Treatments (1)-(3) are recommended for large scale propagation of tagasaste whereas treatment (4) is recommended for experimental studies in which a limited number of samples is needed. Ultra-structural changes in the seedcoat epidermis after breaking of seed dormancy are reported and the relationship between seed dormancy and the ecology of tagasaste and escobon suggests C. proliferus is a pyrophyte species.