Nigeria is the world's largest cassava producer — about 60 million tonnes a year, roughly a fifth of global output. That production rests on a breeding lineage that begins with the International Institute of Tropical Agriculture (IITA), Ibadan, and the National Root Crops Research Institute (NRCRI), Umudike — the two Nigerian institutions that hold the largest cassava germplasm collections in Africa.
The TMS (Tropical Manihot Selection) series began with TMS 30572 in the mid-1970s, the first widely adopted cassava mosaic disease (CMD)-resistant cultivar in West Africa. Successor lines — TMS 4(2)1425, TMS 82/00058, TMS 92/0326, TMS 96/1632, TMS 98/0581 — carried resistance into virtually every African cassava production system. The breeding model was: cross IITA's CMD-resistant donor lines into farmer-preferred local clones, multi-location test in Nigerian agroecologies, release through NRCRI, then licence across the continent through the CGIAR network.
The TME (Tropical Manihot Esculenta) series, derived from landraces collected in southern Nigeria and Cameroon, added CMD resistance from a different genetic background (the *CMD2* gene) — important because it gave the breeding programme a second line of defence when CMD resistance broke in successor virus strains.
In 2011 NRCRI and IITA released TMS-419 (and follow-on TMS-580 and TMS-595), the world's first vitamin-A biofortified cassava, produced in partnership with HarvestPlus. The orange-fleshed roots deliver up to 40% of a young child's daily vitamin A requirement at typical consumption levels.
The downstream Nigerian processing economy — industrial starch, ethanol, glucose syrup, high-quality cassava flour — has never matched the breeding success. The cultivars are world-class. The factory that should consume them is, in most years, idle.