Tandem Effect of Bio-Fortification on Dry Matter Content and Gari Yield of Some Yellow Root Cassava (Manihot esculenta Crantz) Varieties

Bio-fortification of cassava increased its total carotenoid content (TCC) but may have boomerang effect on key quality traits of cassava like dry matter content (DMC). Meanwhile, DMC of cassava reflects its true biological and product yield. Therefore, this study was conducted to determine the relationship between TCC of some novel yellow root cassava varieties (YRCVs) and each of DMC and gari yield. Three bio-fortified YRCVs (IBA070593, IBA070539 and IBA011368) and a white root variety (TMSI30572) as check were harvested 12 months after planting. The TCC (µg/g) and DMC (%) of the fresh storage roots were determined following standard procedures. Subsequently, the fresh storage roots were processed into gari and gari yield (t/ha) was estimated. Data collected were subjected to descriptive statistics, analysis of variance at 5% level of probability and correlation analysis. The check variety lacked TCC but had significantly higher DMC (34.34%) and gari yield (3.40 t/ha) than other varieties except variety IBA070593 for DMC (33.95%). Total carotenoid content of the bio-fortified cassava varieties ranged between 7.81 µg/g (IBA011368) and 10.23 µg/g (IBA070593). Among the YRCVs, IBA070593 consistently had the highest DMC (33.95%) and gari yield (3.2 t/ha) while IBA070539 had least values of 24.63% and 2.2 t/ha, respectively. The TCC of the fresh storage roots correlated negatively with DMC (-0.22) and gari yield (-0.22). Notably, IBA070593 had a good combination of high TCC, DMC and gari yield, hence, it can deliver high gari yield and TCC to processors and consumers, respectively. Propagation of variety IBA070593 is therefore encouraged because it can offer the triple benefits of food, nutritional and financial security.