Correlation of Chemical Compositions of Cassava Varieties to Their Resistance to Prosiephanus truncatus Horn (Coleoptera: Bostrichidae)

ABSTRACT. The preference of cassava as a major host by Prostephonus truncotus Horn is a major c onstraint to ample production of cassava,

tvumibot esculenta Crantz and storage. This study analyzed the nutritional and secondary metabolite compositions in 15 cassava

varieties, evaluated levels of damage and reproduction by P. truncatus, and assessed their resistance to attack. One hundred grams 01

dried cassava chips in 250'ml Kilner jars were infested with 10 adult larger grain borerof 0-10 days old and held for 3 months. The nmritional

and secondary metabolites compositions of the dry cassava chips were determined using the method of Association of Anal'y'tic,,1

Chemists . Chip perforation rates in the cassava varieties ranged from 17.7 to 71,6%. The weight of cassava powder varied by about

threefold. The final number of larger grain borer in the cassava varieties varied by about sixfold with ll3 in 01/00110 and 379 ill 01/1368.

Hvdrocvanic acid content content varied by over lO-fold and correlated negatively with number of larger grain borer. Flavonoid content

varied by ~·1O%. Tannins and saponin content of the cassava negatively correlated with number of adult P truncatus. The cassava varieties

95/0166, 92/0326, 01/0040, 05/0024, and 311 91934 had selection index 0.8 were classified as susceptible. The resistance to high damage in the resistant varieties

was conferred by secondary metabolites such as tannins, saponins, alkaloids, and hydrocyanic acid content. The genetic variation rn

cassava varieties could be explored to breed resistant cassava varieties for use in larger grain borer-endemic areas.