Germination Constraints on Ricinodendron heudelotii in Cameroon

摘要

Ricinodendron heudelotii is a woody forest plant in the process of domestication in Cameroon. Due to its flavor and good nutritional value, demand for its seeds has increased both within the region and beyond. This study investigated the major factorshindering germination of the species. Seeds collected in 2011 and 2012 were subjected to mechanical and chemical scarification, and fungicide treatments, in addition to different storage periods. Results revealed that seed coat dormancy, storage duration, and diseases were major factors affecting germination. Hammer-based mechanical scarification, followed by soaking seeds in water for 24 h significantly improved seed germination (88%), while thermal and sulphuric acid scarification did not improve germination compared to the control (3%). The interval between planting date and first germination was 8 d, while mean germination period for seeds that were scarified with a hammer was 13 d. An ideal storage period of 6 months for R. heudelotii seeds is recommended for best germination results. Although thiram fungicide application had no significant effect on germination, it reduced the number of infected seeds and seedlings after emergence. The presence of necrotic cotyledons, seed rot, and necrosis oncotyledonal leaves after germination was indicative of the susceptibility of R. heudelotii seeds to various pathogens. Results of this study provided additional information to address germination constraints of R. heudelotii in Cameroon.