Induced mutation breeding as a tool for the genetic improvement of cassava landraces for high starch and delayed post harvest deterioration (PPD) in Ghana

Cassava a major staple in Ghana that contributes 22% of Agricultural Gross Domestic Product provides high and reliable cheap source of carbohydrates for over 200 million people has assumed an industrial and cash crop status in Sub- Sahara Africa. However, cassava suffers from pest and diseases, with the starchy roots rapidly deteriorating within 24 to 72 hours after harvest resulting in close to 20% loss in the fresh roots. Cassava crosses for the introgression of useful genes for delayed Post harvest Deterioration where Molecular Markers Assisted selected (MAS) inter-specific hybrids with delayed PPD properties were crossed with preferred land races. Inter-specific hybrids of walkererea evaluated showed remarkable disease resistance in all ecological zones tested, PPD score Clone CR 52A-25 additionally showed no signs of post harvest physiological deterioration after the seventh day of harvest and AR 14-10 had unique starch properties for potential industrial use. Induced mutation of tissue culture plantlets of four preferred cassava landraces 'Cedi bankye', 'Sisipe 166', 'Debor' (ancient variety) and 'Dabodabo' (zigzag plant architecture with stay green properties) at two levels of doses 15Gy and 12 Gy were at V5 stage hardened and established in a replicated field trial in three locations. Initial results showed high root yields for doses of 12Gy and remarkable resistance for ACMD (1.5 score) for all mutants at 3MAP, Debor at both doses showed the best vigour for all locations. Induced mutation of botanical seeds from landraces and inter-specific hybrids of walkererea at 200 and 300Gy showed moderate disease reaction and plant vigor. The mutants would be tested alongside the control for starch and PPD at 9MAP and 12MAP. (author)