Seed quality development in sumauma (Ceiba pentandra

Abstract

Seed quality development was studied in the tropical tree sumauma (Ceiba pentandra [L.] Gaertn.) in Amazonia. The onset of ability to germinate and to tolerate desiccation to 4% moisture content was detected 5d after mass maturity (MM, defined as the end of the seed-filling phase), when seed moisture content was 51% (f.wt basis), and as fruit and seed colour changed from green to grey and from yellow to black to dark brown, respectively. Maximum seed quality (assessed by ability to tolerate desiccation to 4% moisture content, subsequent seedling growth, and subsequent seed longevity in hermetic storage at 40 ± 0.5°C with 15 ± 0.2% moisture content) was maximal in seeds from all fruits collected 13d later (18d after MM) when maturation drying had reduced seed moisture content naturally to 20% and as fruits began to be shed from the tree. Seed quality did not decline over the subsequent 31d within fruits that remained on the tree. We conclude that high quality sumauma seeds can be obtained by collecting fruits at the end of the seed maturation drying phase shortly before the fruits are shed from the tree. The results provide further evidence that the widely-quoted hypothesis that seed quality is maximal at the end of the seed filling-phase and that viability and vigour decline thereafter is incorrect.