Yam is Nigeria's third-most-valuable food crop after cassava and maize, with about 50 million tonnes a year — 70% of global production. The crop is genetically difficult: dioecious, vegetatively propagated, with low and erratic flowering, which made conventional crossing slow.
The National Root Crops Research Institute, Umudike — under successive breeders including R. Asiedu (in IITA partnership), N. Maroya, A. Adelekan and the IITA Yam Breeding Unit — produced the TDr series of improved white-yam clones, beginning with TDr 89/02565 and continuing through TDr 8902677, TDr 9519177, TDr 0900128. Each line was selected for tuber yield, dry-matter content, anthracnose resistance, and pounding quality (*iyan*).
In 2017, an international consortium with substantial NRCRI and IITA participation published the first reference genome assembly of *Dioscorea rotundata* — opening the crop to marker-assisted breeding for the first time. The sequencing was done at the Iwate Biotechnology Research Center in Japan; the germplasm, phenotyping, and breeding population came from Umudike.
Yam is one of the very few crops the global breeding industry has largely ignored — too localised, too vegetative, too hard. Almost everything that exists in modern yam science was done in Nigeria.