Introduction. Canarium schweinfurthii, a tree species in the rainforest of Nigeria whose fruits are intensively gathered and eaten, is seriously endangered because of poor seed germinability and usage. Our study examined the pattern of seed distribution of C. schweinfurthii in the soil from the stem base of the parent plant and through the soil profile, and it assessed the seed level of germinability. Materials and methods. Four stands of C. schweinfurthii were selected from a study area in Southeastern Nigeria. Soils were collected from six distances from each trunk base (1 m, 5 m, 10 m, 15 m, 20 m and 25 m) and at four soil depths (0–5 cm, 5–10 cm, 10–20 cm and 20–30 cm); then seeds of C. schweinfurthii were isolated from the cores. Moreover, the percentage of viability and germinability of the seeds collected from each distance and depth were determined. Results. The maximum number of seeds occurred at 1 m from the trunk base (82.3 seeds·30 cm–2), which was 55% of the total collected seeds, and no seed occurred beyond 20 m from the trunk base. The mean number of C. schweinfurthii seeds occurring at 0–5 cm soil depth was 51.3 seeds·30 cm–2, which was the highest from any profile. No seeds occurred below 20 cm. Sixty-seven percent of the total 148 seeds collected were considered viable, with about 80% of them occurring at the 0–5 cm soil depth. Even with the pre-sowing treatment (cutting the hard endocarp), only 30.8% of viable seeds collected from 0–5 cm soil depth were able to germinate, while 10% of those collected from 5–10 cm depth germinated. Conclusion. The localization of over 80% of C. schweinfurthii seeds within a 5-m radius from the stem base and 65% within 0–5 cm soil depth encourages easy fruit gathering by local sellers and leads to depletion of the seed bank. Seedling multiplication, protection of stands and domestication need to be initiated to lift C. schweinfurthii out of endangered status, considering the demand for the fruit and poor seed germination due to the hard endocarp.

Introduction.Garcinia kola, a multi-purpose fruit tree, produces fruit, seeds, roots and stem which are extensively used in Nigeria, Ghana and other West African countries for dental care. Cultivation of this fruit tree is limited because of poor seed germination. Our study therefore aimed at improving seed germination properties which will promote cultivation of G. kola by rural farmers. Materials and methods. Seeds taken from a single tree of G. kola were treated with cold water (22 °C), hot water (60 °C) and gibberelic acid (0.5 g × L-1) for various lengths of time. They were then put to incubate in sterilized river sand or a thick transparent polyethylene bag to evaluate the capacities of seed to be germinated under such conditions. In addition, the seed moisture content at harvest was also reduced to various levels before incubation in polyethylene bags to determine the critical moisture rate necessary for seeds to germinate. Results. The seeds incubated in the river sand without any treatment before sowing had an average time of germination of 71.2 d and a total percentage of germination of 28% whereas those incubated in polyethylene bags had an average time of germination of 25.8 d and a total percentage of germination of 62% . The cold water treatment, irrespective of the incubation method, did not significantly affect either the mean germination time or the total germination percentage. However, it significantly reduced the spreading out of the seed germination to 5.4 d. The seed pretreatment with gibberelic acid prolonged at the same time the average time of germination and the spreading out of the germination. The seed water content at harvest (50.4%) allowed the best rate of seed germination and the shortest spreading out of the germination period. Conclusion. The pretreatment of freshly harvested seeds with cold water followed by an incubation in a thick transparent polyethylene bag proved most effective in enhancing the germination of G. kola seeds. This procedure has to be recommended to promote the cultivation of this species.

Introduction. Des géniteurs d'amandiers autocompatibles ont souvent été utilisés pour introduire le caractère d'autocompatibilité dans leur descendance. Cependant, lors de tels programmes de création variétale, des problèmes de germination des graines obtenues et des difficultés de survie des jeunes plants ont été mis en évidence. L'objectif des travaux réalisés a été de quantifier les effets de la consanguinité sur certaines caractéristiques du développement des semences issues de tels géniteurs. Matériel et méthodes. Les descendances de la variété autocompatible Tuono autofécondée ou croisée avec des géniteurs mâles génétiquement éloignés ont été suivies et comparées, de la germination à l'âge de 3 ans. Les taux de germination, de levée et la vitesse de levée ont été évalués. Puis la croissance des plants a été étudiée à partir de la mesure régulière du diamètre de l'axe et de la hauteur des plants. Le nombre de nœuds, d'entre-nœuds, de rameaux anticipés et le taux de mortalité des plantules ont également été notés. Résultats. Par rapport aux semences issues d'allopollinisation, les graines issues d'autofécondation ont présenté un taux de germination moyen inférieur (61 % contre 81 %) ; la vigueur de leurs plantules, leur croissance radiale et apicale et le nombre de rameaux anticipés formés ont été plus faibles ; leur taux de mortalité a été supérieur (28 % contre 0,6 %). Discussion et conclusion. Les anomalies mises en évidence au cours de ces travaux seraient dues à l'endogamie et liées à l'accumulation de gènes défavorables dans la descendance consanguine.