GENETIC VARIATION IN FOLIAGE AND PROTEIN YIELD OF SOME ELITE CASSAVA (MANIHOT ESCULENTA CRANTZ) GENOTYPES IN GHANA

Abstract

Cassava (Manihot esculenta Crantz) contains high levels of proteins and minerals which can be utilized for human and animal consumption. A randomized complete block design with three replications was established to evaluate 25 cassava genotypes for their foliage and crude protein (CP) productivity as well as growth persistency under rain-fed conditions. The foliage comprising the leaves and the young tender stems were periodically harvested from 20cm above ground starting from three months after planting and every three months until root harvest at 12 months after planting. Apart from the first harvest, significant genotypic differences (P≤ 0.05) were established for foliage yield for the subsequent harvest days. The highest total cumulative fresh and dry foliage yields were 41.07t/ha and 15.73 t/ha respectively. Cumulative crude protein yield also ranged between 0.64 t/ha and 1.63 t/ha. Periodic pruning resulted in much higher foliage and protein yields than when the foliage was obtained only once at root harvest. Strong phenotypic correlations were observed among most of the different traits. Protein yield was observed to be highly correlated with fresh and dry foliage yield whereas a weak and non-significant correlation was recorded for protein content and all the other traits except with number of shoots and protein yield. Harvesting time also had a significant effect on foliage and crude protein yields with the second harvest giving a much higher foliage production for most of the genotypes. High heritability (broad sense) estimates were observed for most of the traits studied. These traits can be used to select genotypes for foliage and protein production.