The objective of this work was to determine reaction of selected cassava cultivars to anthracnose disease (CAD). Eighteen cultivars were evaluated over 3 years (2003-2006) and assessed for natural CAD infection between 2 - 6 months after planting.  The assessment of CAD incidence was based on observations of symptoms on naturally infected plants fortnightly for 12 months. The height of the first canker from the ground level (mm) was measured and the number of cankers per plant counted. The length and the diameters of the cankers on each infected stem were measured and the area was calculated using the formula for area of a circle (πr2) fortnightly for 6 months. Disease incidence in all trials was recorded as the percentage of infected plants in each host plant line. Cultivar TMS 30211, TMS 4(2)1425 and TMS 30001 had cankers high up on the stem (400 -1,530 mm) which showed that they were not attacked in the early stages of growth.  Cultivars Akwakwuru, 91/02324, Nwageri, 97/3200, 96/1642, TMS 30572 and TMS 91934 had cankers closer to the ground (50.7 – 225 mm), indicating that they were infected in the early stages of growth. Cultivars TMS 30555, 96/1642, 91/02324, Nwaocha, Akwakwuru and Nwageri had high disease severity score ranging from 3.35 - 4.0 and large cankers of size 8.5 – 32.5 mm2. These susceptible cultivars are not recommended to farmers or breeding programmes because their use would lead to build up and spread of CAD. Cultivars TMS 91934, TMS 4(2)1425, TMS 30211, TMS 30001 and 98/0510 had small cankers of size 1.8 -13.5 mm2  in the first trial year (2003-04) and low severity score ranging from 1.0 – 2.26 in the third trial year (2005/06), and did not develop any cankers in the third trial (2005/06).With these desirable characteristics, these cultivars are regarded as resistant and can be recommended for cultivation by farmers and further use in research. .

Key words 
Anthracnose disease, cassava, resistance, severity, Nigeria

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