Study of the Germination of Scarified Seeds of Burkea africana Hook. For Its Domestication in Chad

The objective of this work was to determine new approaches that could improve the germination quality of Burkea africana seeds under reproducible conditions and by means available to farmers with a view to its propagation. The tests concerned the influence of three pre-germinative treatments. It is about the light scarification (Scl), medium scarification (Scm) and deep scarification (Scd) of seeds in order to determine some parameters of germination that are the latency time, the time of germination, the rate of germination and the speed of germination. The treated seeds were sown in transparent germinators lined with hydrophilic paper and then after the appearance of radicles, the plants were transplanted on five types of substrates (black soil, fine sand, sawdust, mixtures 1/1 of sawdust-black soil and 1/1 of sawdust-fine sand). The results obtained by the deep (Scp) and medium (Scm) scarification compared to those of the light scarification and the control, showed a clear reduction of the lag time (3 days/15 days (control). At the 5% threshold, germination times 6.27 × 10-1 (Scd) and 6.01 × 10-1 (Scm) were significantly influenced. Germination rates 4.18 × 10-1 (Scd) and 3.92 × 10-1 (Scm) are also influenced by the pretreatment. Germination rates are significantly improved (80%). Regardless of the under treatment, the substrate “sawdust and fine sand” improves the germination of scarified seeds by 14.07% more compared to the substrate “fine sand” at the 5% threshold. The mechanical scarification and the type of substrates thus influence positively and homogeneously the germination of seeds of Burkea africana. The domestication of this species is thus possible and can be considered for useful purposes.

Impact of Pretreatment on the Germinative Characters of Seeds of Stereospermum kunthianum Cham. (Bignonaceae) for Its Domestication in Chad

The objective of this research is to lift the dormancy of seeds of S. kunthianum in with a view to domesticating them. In this experiment, we used the soaking of seeds in sulfuric acid for different durations (10 min, 30 min and 1 h). The treated seeds were sown in transparent germinators. The explants obtained were then transplanted into pots containing five types of substrate (black earth, fine sand, sawdust, mixtures 1/1 of sawdust/black earth and 1/1 of sawdust/fine sand). This second test made it possible to determine the rate of germination on the substrate. The results obtained compared to those of the control showed a clear reduction in the latency time or germination time (62 hours) instead of 6 days (control), in the germination time 3 days/7 days (control) and a very high germination rate (100%). At the 5% threshold, soaking for 10 min and 30 min (100%) is the best result on the germination of S. kunthianum seeds. Soaking for 1 hour gives (7%) very low. After transplantation of the explants, the percentages obtained independently of the treatments show that the 1/1 mixtures of sawdust/black earth (75.19%), black earth (73.33%) and sawdust/fine sand (66.30%) have a higher performance than the others. The type of germination is epigeal. This work makes it possible to domesticate S. kunthianum in Chad.

Effects of Scarification and Substrates on Seed Germination Quality for Domestication of Stereospermum kunthianum(Bignoniaceae)

The demand for medicinal plants at the origin of phyto-drugs,like all ethnobotanical plants,threatens their existence today.The aim of this work was to determine suitable methods for optimizing the possibilities of regenerating Stereospermum kunthianum.To achieve this objective,3 levels of mechanical scarification(light scarification,medium scarification and deep scarification)were applied to the seeds of this species using a rough instrument,and 5 days after germination,the seedlings were transplanted into 5 types of substrate to study their effects on seedling growth.The length of the seedlings was measured using a graduated ruler.The results obtained showed that the best latency time was 2 days for average seed scarifications.The highest germination half-time was 4.00±0.06 days observed for average seed scarification,the highest germination speed was 22.50±1.00 and the highest germination rate was 100.00%±0.00%for average scarification.The homogeneous substrate mixes black earth/woodsilk and Fine sand/woodsilk were more effective for seedling growth(1.9 cm/day in the juvenile state)and development.Medium seed scarification is the most effective method for regenerating Stereospermum kunthianum,and the black earth/wood shavings substrate mix is the best for its cultivation.