An Alternative Low Cost Multiplication Technique: Natural Substances for Regenerating Plantlets from Mini Tubers of Sweet Potato (Ipomoea batatas, L.)

Aims: This study was conducted specifically to develop a low cost rapid plantlet multiplication process easily affordable for farmers to enable them speedily generate plantlets for their farms from mini tubers of sweet potato variety, TIS 87/0087.

Study Design: The experimental design was a completely randomised design with three replications. Analysis of variance was used (P=.05) to test treatment effects in a completely randomized design and mean comparison was by LSD.

Place and Duration of Study: The study was carried out between February and April 2019 in the plant culture laboratory of the Department of Plant Science and Biotechnology, Rivers State University, South-South, Nigeria.

Methodology: Mini tubers of sweet potato (Ipomoea batatas, L.) were preconditioned by soaking in a 1:10 ratio of natural substance to water for 12 hours before planting in soil. The natural substances comprised coconut water, grapefruit juice and honey with water as control.

Results: Mini tubers primed with grapefruit juice and coconut water sprouted significantly earlier (P=0.05) (7 days and 10 days respectively) than the control (water) which sprouted after 19 days. However, there was no significant difference in time to sprouting between mini tubers primed with honey (16 days) and the control (19 days). Mini tubers primed with grapefruit juice, coconut water and the control did not differ significantly (P=.05) in the number of initial plantlet sprouts but mini tubers primed with honey had significantly lower initial sprouts than others. On average, coconut water primed mini tubers produced significantly higher (P=.05) total number of regenerated plantlets compared to the other treatments and continued regeneration of plantlets longer than other treatments. Coconut water regenerated almost 3times the number of plantlets regenerated by mini tubers soaked in water. Mini tubers primed with honey stopped sprouting after 29 days which was significantly earlier (P=.05) than those primed with grapefruit juice (38 days), water (46 days) and coconut water (51 days).

Conclusion: This study found that mini tubers of sweet potato after a preconditioning treatment by soaking in dilute coconut water (1:10 coconut water : water ratio) for 12 hrs before planting regenerated almost 3times the number of plantlets regenerated by mini tubers soaked in water for the same period.