E.C. Nnodu and A.G.O. Dixon
Eight newly developed low cyanide cassava varieties – NR Series— 84292, 84151, 8420, 84104 (from NRCRI, Umudike), TMS Series-71762, 30474, 82/00033 and 82/00447 (from IITA, Ibadan) were evaluated for yield and resistance to major cassava pests and diseases in different agroecologies in Nigeria during the 1995/1996 and 1996/1997 cropping seasons. They were evaluated with and without fertilizer applied. Variety TMS 4(2)1425 which is a low cyanide variety already released to farmers in Nigeria was used as the control. Also Vars. NR 8082 and TMS 30572 which are high cyanide varieties were included to compare their performances against the low cyanide varieties. Pest damage and disease seventy scores were also taken. The results showed that the varieties responded differently to different environments but varieties TMS 82/00447, TMS 82/00033 and TMS 71762 were the top three yielders across most locations during the first year with or without fertilizer applied. The same is true for the second year. When the yields for the two years were combined, TMS 82/00447 was the best yielder followed by TMS 82/00033 and then TMS 71762. They had same or better yield than the control at many locations and in some. The same is true when compared with the high cyanide varieties. All varieties evaluated were tolerant to bacterial blight, anthracnose and mealybug attack. African cassava mosaic virus disease and cassava green mites damage was respectively the most important pests and diseases observed. Based on the two year data varieties TMS 82/00447, TMS 82/00033 and TMS 71762 are recommended for release to farmers to increase their stock of low cyanide cassava varieties.