Application of embryo culture in germinating African cassava mosaic disease resistant gene mapping population 217

In a study to map out the genes conferring resistance to African cassava mosaic disease (ACMD), a cost-effective protocol for zygotic embryo culture developed at the International Institute of Tropical Agriculture (IITA) using 1/2 strength Murashige and Skoog's basal media was employed to germinate the F1 populations. The F1 crosses were generated from cross combinations between ACMD resistant and susceptible and local cassava germplasm. These crosses were TMS 30572 x TME 117, TMS 30572 x TME 4, and TMS 30555 x TME 3, giving three mapping populations. Four weeks after explanting embryo axes, progenies of the F1 cross of TMS 30555 x TME 3 performed best with 88% of the total explanted embryos producing two or more nodes, followed by those of the F1 cross of TMS 30572 x TME 4 with 79%, and TMS 30572 x TME 117 with 77%. A small percentage of each of the mapping population germlings had 4 to 5 nodes, and 3, 5, and 9% in F1 crosses of TMS 30572 X TME 117, TMS 30572 x TME 4, and TMS 30555 x TME 3, respectively.