Efficient production of transgenic plants by Agrobacterium-mediated transformation of cassava (Manihot esculenta Crantz)

An efficient and reproducible method was developed for Agrobacterium-mediat ed transformation of embryogenic suspension cultures of cassava. LBA4404(pT OK233), containing the nptII, hph and gus marker genes, was used in the exp eriments. Chemical selection by means of kanamycin was used to establish 10 37 antibiotic resistant callus lines, of which 526 showed GUS expression. O f the 241 callus lines that were transferred to maturation medium 219 forme d somatic embryos. Thirty-seven of the 38 lines that were transferred to ge rmination medium produced plants. GUS-positive plants could be obtained fro m 31 lines; in 14 of those lines 100% of the produced plants were GUS-posit ive, the remaining 17 lines yielded GUS-positive plants at an average of 72 %. The transgenic nature of these plants was confirmed by Southern blot ana lysis.