Effect of Host Genotypes and Weather Variables on the Severity and Temporal Dynamics of Sorghum Anthracnose in Ethiopia
2010
Chala, A. | Alemu, T. | Prom, L.K. | Tronsmo, A.M.
The severity and temporal dynamics of anthracnose on susceptible (BTx623 and AL70) and resistant lines (2001 PWColl No. 022 and 2001 HararghieColl No. 12) were studied in field plots during the 2007 and 2008 growing seasons in southern Ethiopia. The initial, final and mean anthracnose severities and area under disease progress curves were used as criteria to evaluate the response of the genotypes. Over the two years, the initial, final and mean anthracnose severities ranged from 0.88 to 16.13%, 7.56 to 78.38% and 3.57 to 46%, respectively, while area under disease progress curve averaged for the two years ranged from 221.31 to 2951.88. All the evaluation criteria showed highly significant variations (p<0.0001) among the genotypes and the Ethiopian genotype 2001 PWColl No. 022 consistently had the lowest disease levels regardless of the evaluation criteria and growing season. The disease appeared rather late and progressed slowly on this genotype. On the other hand, the exotic cultivar, BTx623, showed the most sever anthracnose infection. Initial anthracnose severity was significantly higher and the disease developed rapidly on BTx623 than on the other three genotypes. The other two genotypes showed intermediate response and progression of the disease. Correlation and regression analyses revealed a significantly strong association between rainfall and anthracnose severity but temperature appeared to have little/no impact on the development of anthracnose in the field. The present study confirmed the effect of both host genotypes and weather, particularly rain on anthracnose development. The Ethiopian sorghum genotype 2001 PWColl No. 022 was recommended as stable source of resistance against this important disease.
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