Abstract:
Due to poor root quality traits in improved, disease resistant cassava (Manihot esculenta Crantz.)
varieties and hence low acceptability among farmers, a study was undertaken to improve these
varieties by crossing them with disease susceptible, farmer preferred local landraces. Five improved
varieties and four local landraces were used and hybridisations among them were made in a poly-cross
nursery block. Starch isolated from the nine cassava varieties and their F1 progenies was analysed for
physicochemical and functional properties. Significant differences were observed between varieties,
progenies and within the F1 progenies. The amylose content ranging between 19.0 - 25.0% was
negatively correlated to swelling power and solubility but positively correlated to starch content.
Average starch granule sizes ranged between 7.0 - 12.0 mm, though smaller granules ranged between 2
- 6.9 mm and large granules between 13 – 20 mm. Granules were mainly truncated in shape and similar
across varieties and their progenies. Individual parents had peak viscosity, set back viscosity and
viscosity at breakdown higher than the progenies suggesting inherent genetic and biochemical
differences among parents used in the study. Variations were also observed in the parents and
progenies for starch swelling power, solubility and starch content on dry basis. Starch associated
molecules such as proteins and lipids did not vary significantly but dietary fibre significantly (P< 0.05)
varied both in parents and F1 families. Significant correlations (r > 0.45) were observed among starch
properties including swelling power and breakdown viscosity. Based on these results, selections for
lines with different starch quality and quantity properties can be made among the F1 families for future
dietary and industrial uses.
