Abstract

This study was undertaken to detail starch characteristics among cassava varieties and compare them to their improved progenies. Cassava starch was extracted from roots of both the parents and progenies of two popular Ugandan local varieties (Bamunanika and Nyaraboke) and three popular elite varieties (NASE 10, TME 14 and 95/SE/00036) and their properties compared. The pasting and rheological properties showed a unique pasting curve in the progenies compared to the parents with significantly low peak viscosities among the progenies. Percentage crystallinity as determined by X-ray crystallography was on average four points higher in parents compared to progenies. There were no significant differences in the average amylose contents (17 - 20%) and starch contents (about 81%) in both the progenies and their parents. Significant relationships were observed between crystalline and pasting properties of the starch among the clones and parents. The above differences suggest possible variations in the amylopectin chain structure and starch molecular properties attributable to differences in the starch branching enzyme among the progenies and their parents.

Key words: Starch, crystallinity, pasting property, amylopectin structure.