Effect of staking and non-staking systems on disease severity, yield and quality attributes of yams (Dioscorea alata)

Aims: The aim of this study was to evaluate the effect of staking and non-staking systems on disease severity, yield and quality attributes of yams. Methodology: High costs and lack of planting materials, labour, staking and inappropriate knowledge on production techniques are major constraints of yam production in Sierra Leone. A total of seven promising hybrid genotypes of yams from International Institute of Tropical Agriculture and one local cultivar, Pulli, were evaluated for yield, reaction to local pest and disease and desirable market traits during 2011 and 2012 in three agro-ecological zones of Sierra Leone. The experiment was laid out in randomized complete block replicated thrice at the experimental sites of the Njala Agricultural Research Centre. Results: Results revealed higher disease pressure in non-staked plots compared to staked plots. Fresh tuber yields were significantly higher in staked plots than the non-staked plots. Five genotypes with yields ranging between 11.8 and 14.7 t.ha-1 significantly out-yielded Pulli (9.1 t.ha-1) in the staked plots, while only genotype TDa 02/00012 (11.9 t.ha-1) significantly out-yielded Pulli (7.1 t.ha-1) in the non-staked plots. Farmers’ preferences for all genotypes were similar to that of the local cultivar. Staking contributed 30.5% mean yield increase compared to non-staking. Makeni had the highest percent mean yield increase due to staking (38.5%) compared to Njala (29.7%) and Kenema (26.4%). Conclusion: Staking is beneficial in yam production contributing an average of 28.2% more fresh tuber yields than non-staking. Genotypes in staking system were more tolerant to in-field local diseases, thereby significantly out-yielding those in non-staking system. Genotypes TDa 98/01174, TDa 98/01176, TDa 02/00012, TDa 98/01168 and TDa 00/00194 had stable resistance to in-field diseases in the staking system and desired food quality traits compared to the check variety, Pulli. Findings have good implications for multiple disease resistance breeding for various production systems as the different genes controlling these traits could be pyramided into an ideotype. Similar technique could be used to breed for yield and other desired food quality traits