Effect of pre-sowing and incubation treatment on germination ofGarcinia kola(Heckel) seeds

Abstract

Effect of pre-sowing and incubation treatment on germination of Garcinia kola (Heckel) seeds. Abstract-Introduction. Garcinia kola, a multipurpose 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. Nigeria / Garcinia kola / plant propagation / seed / germination / germinability / seed treatment Effet des traitements avant semis et des techniques d'incubation sur la germination de graines de Garcinia kola (Heckel).

Garcinia Kola Heckel Seeds Dormancy-Breaking

“…Decoated seeds soaked in hot water (70°C) failed to germinate due to embryos destruction by the warm treatment. Germination failure was previously reported when soaking Garcinia kola seeds in warm water (60°C) for 8 hours [11] and this confirm that the warm water treatment affected negatively Garcinia kola seeds germination. Coated seeds in hot water could germinate showing that seed coat may protect in certain extent embryo from destruction by warm.…”

“…Garcinia kola seeds are sensitive to desiccation that usually decreases seed viability. It was revealed that the germination rate decreased with the seed moisture content and at 20.2% moisture content every seeds died and failed to germinate; the seed water content at harvest (50.4%) allowed the best germination rate and the shortest spreading out of the germination period [11]. Comparable results were obtained for Garcinia cowa, a tropical recalcitrant seed.…”

“…The effectiveness of the pineapple juice and the banana trunk treatments may be due to the presence of some compounds that reduce the dormancy-induction properties in the seeds. The hypothesis of embryo dormancy on Garcinia kola seeds was reported basing on the presence of substance associated with germination inhibition such as phenol in the seeds [11]. In this case decoated seeds soaking in cold water may decrease the content of such compounds and promote seed germination.…”

“…The treatments tested were selected based on firstly the information published in scientific papers [11] and secondly non-published information provided by scientists. Dormancy-breaking techniques combined seed coat treatment and pre-germination treatment.…”

“…Previous studies investigated on Garcinia kola Heckel and Garcinia cowa Roxb. seeds germination [7,11]. Both studies were carried out in laboratory conditions and part of the outcomes couldn't be implemented by small farmers.…”