Evaluating the Effects of Staking and Planting Dates on the Yields of African Yam Bean, Sphenostylis stenocarpa in Nigeria

Aims: To evaluate the effects of staking and planting dates on the seed/tuber yields of African yam bean (AYB).

Study Design: The fields were laid out in split-plots in randomized complete block design

Place and Duration: Field experiments were conducted at Ebonyi State University, Abakaliki, Nigeria during 2009/10 farming seasons.

Methodology: Three different planting dates were used as the main-plot treatments, while staking and non-staking formed the sub-plots. Seven accessions of AYB were planted in the sub-plots. Five plants were randomly selected from each accession/treatment and tagged for data collection. Each seedling was staked independent after germination, while the non-staked plants were allowed to trail on the ground guided. Collected data were subjected to analyses of variance. Mean separation was carried out by Fisher’s protected LSD test. Pearson correlation coefficient (r) was used to determine the relationship between yields, planting dates and staking.

Results: The results indicated that all the AYB accessions performed better when they were staked and planted earlier in May of each season with greater seed/tuber yields, which differed significantly (P < 0.028) from those that were not staked and planted later in each of the season. Of all the accessions assessed, TSs86 was the most productive with the highest seed yield and differed significantly (P < 0.015) from the rest except TSs48 that even gave better seed yield during 2010, while TSs84 had the least seed yields. Results on the tuber yields showed the same trend in relation to the treatments. The tuber yield showed that some accessions could produce above 2 Mg ha-1 of tubers per hectare; however tuber yield showed inverse relationship to that of the seed yield across the accessions with the highest tuber yield recorded in TSs93 and least in TSs86.

Conclusion: For increased seed/tuber yields of AYB in Nigeria, it has to be staked and planted early in May of each season.