Increasing farmers and breeders access to yam (Dioscorea spp) diversity: The case of Forest- Savannah Transition Agroecology

A study was conducted in five yam-growing communities in the Forest Transition Agroecological Zone of Ghana to identify cultivated yam varieties, their distribution and intensity of cultivation and to document the rate and causes of landrace germplasm loss. Generally, the cultivated varieties ranged from 9 to 16 with a mean of 12. The most diversity was found in Sankore (Asunafo South District), followed by Sampa in the Jaman North District, Asantekwa in the Kintampo District, Ejura in the Ejura-Sekyedumase and Mim in the Atebubu/Amantin Districts with 16, 15, 12, 11 and 9 cultivated varieties respectively. Dioscorea rotundata is most widely cultivated species of yam followed by Dioscorea alata, Dioscorea cayenensis, Dioscorea praehensilis and Dioscorea bulbifera respectively. Factors such  as good culinary characteristics, high yield, seed generation capacity, good storage characteristics and resistance to biotic and abiotic stresses were important criteria for selection of variety. The market and utilization were major determinants of continual cultivation of a variety or its neglect.   Key words: Agro-morphological, cultural, environmental, Ghana, technological.