| Abstrakt: |
Yam anthracnose is caused by the pathogenColletotrichum gloeosporioidesPenz. and has been identified as the most important biotic constraint to yam production worldwide. Rapid assessment of the disease is vital to its effective diagnosis and management. In this study, tissue-cultured yam plantlets of five lines ofDioscorea alataand nine ofD. rotundatawere rapidly assessed for their reactions to two isolates of yam anthracnose. The plantlets, obtained from meristem of the nodal cuttings, were grown for 8 weeks on Murashige and Skoog (MS) basal medium, acclimatised for 3 weeks, hardened for an additional 3 weeks, arranged in screen house in completely randomised design and sprayed with spore inocula prepared from 7 day-old culture of the two strains ofColletotrichum gloeosporioidiesPenz. The relative resistance of the differentDioscoreaspp. was evaluated using three disease indices – severity at seventh day after inoculation, SD7; area under disease progress curve, AUDPC; and disease severity rate, Rd. A modified rank-sum classification method put TDa 1425 and TDr 2040, with rank sum of 2.0 each, as resistant. TDr 2121, TDr 2287 and TDr 2048 were susceptible with rank sum of 27.50, 25.50 and 24.50, respectively.Dioscorea alataTDa 1425 andDioscorea rotundataTDr 2040 were recommended in areas endemic with yam anthracnose, and also as parent lines while breeding for resistance to anthracnose. [ABSTRACT FROM PUBLISHER] |
