Effect of pre-treatment and genotype of kola [Cola nitida (Vent) Schott and Endlicher] nuts on germination, growth, and early yield. (105)
Keywords:Crown surface area, Germination, Growth vigour, Kola, Leaf area, Pod weight
AbstractRapid germination and low variability in the time to germination of populations of kola [Cola nitida (Vent) Schott and Endlicher] nuts are essential for the uniform growth and establishment of the crop in the field. Experiments were conducted to assess the effect of nut pre-treatment on germination and subsequent plant growth of kola. Six kola genotypes and four pre-germination treatments (removing a third of the cotyledons from the distal end of the nut, nut with one cotyledon removed from the embryo, whole nut with inner surface of cotyledons partially scratched and separated with a piece of kola wedge, and a whole nut control) were arranged in a randomized complete block design (two-factor factorial) and replicated three times. Averaged over the genotypes, the removal of one cotyledon from the embryo reduced the time to germination of the first nut and the time to 50% germination by 43.0 and 52.0%, respectively, compared to the control treatment. However, seedling leaf area at 12 months after sowing, tree crown surface area, and mean pod weight at four years after transplanting were reduced by 24.0, 30.0, and 23.0%, respectively, for plants developed from the nuts with one cotyledon removed compared to whole nuts across the genotypes. Partial detachment of the cotyledons before sowing reduced the time to 50% germination by 30% with subsequent plant growth and yield being similar to those developed from intact whole outs. Hierarchical cluster analysis grouped the kola genotypes into two clusters. Variability in the speed and spread of germination and differences in plant growth vigour were minimal within genotypes in a cluster. Thus, grouping kola genotypes and partially detaching the cotyledons using a sharp edge before sowing could facilitate rapid germination, production of vigorous seedlings, and uniform establishment in the field.