Seed morphology and germination of Ensete ventricosum (Musaceae)

Ensete ventricosum is a drought-tolerant, multipurpose crop that has been cultivated in Ethiopia since ancient times. Traditional propagation is vegetative: each of hundreds of existing landraces is a clone. Improved cultivars are needed, which may be achieved through sexual propagation and selection, but this requires knowledge of seed germination. Ripe seeds from five wild and six cultivated plants were studied for seed morphology and germination. Embryos were small in relation to seeds but did not elongate inside seeds before radicle protrusion. The shoot emerged a few days later and the scutellum (haustorium) expanded over several weeks following germination. The endosperm was utilised during early growth. Germination was 5-55% depending on plant source; average germination did not differ significantly between seed lots of wild and cultivated origin. Overall, time to 50% of final germination was 8.5 weeks and no germination occurred after 28 weeks of incubation. Soaking in water for 0 to 96 hours or exposure to sulphuric acid, sodium hydroxide, ammonium nitrate, sodium hypochlorite or hot water before the germination test had no significant effects on germination while scarification or pre-treatment with 70% ethanol had significant negative effects. The seed coat is very hard; nevertheless water uptake occurred, slowly but steadily, in intact seeds. We conclude that E. ventricosum has neither morphological nor physical seed dormancy. Further studies are needed to investigate possible physiological seed dormancy.