Abstract

This study was carried out in two locations in south eastern Nigeria in the year 2008 and 2009, to evaluate growth and yield responses of cocoyam cultivars to rates of NPK 15:15:15 fertilizer. This was aimed at identifying high yielding cocoyam cultivars and optimum rates of the fertilizer for optimum cocoyam production. Two locations: Nsukka (Enugu state) and Umudike (Abia state) were used for this study. The experiment was done in Nsukka location in 2008 and repeated in Umudike in 2009. Five Colocasiaesculenta cultivars (Cocoindia, Nworoko, Odogolo, Nadu and Nkpong) and five rates of NPK 15:15:15 (100, 150, 200, 250 and 300 kg/ha) were tested. The result showed that application of NPK 15:15:15 fertilizer increased growth in cocoyam. However, the highest tuber yield/ha of 37.85 tons/ha at Nsukka and 20.845 tons/ha at Umudike were realized in response to the application of 200 and 250 kg/ha, respectively. Further increases above these rates in the locations caused non-significant decline in tuber yield. The Cocoindia cultivar also produced the highest tuber yield/ha among the five cultivars in both Nsukka (30.10 tons/ha) and Umudike (19.068 tons/ha). It was also observed that higher tuber yield was obtained in Nsukka location than in Umudike location. This study has shown that the application of NPK 15:15:15 fertilizer increased tuber yield in cocoyam grown in the south eastern Nigeria.

Key words: Colocasia esculenta, cultivars, fertilizer and tuber yield.