Submitted to: The Americas Journal of Plant Science and Biotechnology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/20/2008
Publication Date: 8/31/2008
Citation: Erpelding, J.E. 2008. Sorghum germplasm resistance to anthracnose. The Americas Journal of Plant Science and Biotechnology. 2(1):42-46. Interpretive Summary: Anthracnose, a fungal disease of sorghum, commonly appears as spots or elongated lesions on leaves and may result in plant death for high susceptible cultivars. Yield losses of more than 50% have been reported. The disease can be successfully controlled by growing resistant cultivars, but variation and changes in the disease population reduces the long-term durability of resistant cultivars. As a result, additional sources of resistance are needed for sorghum improvement. The sorghum collection maintained by the USDA-ARS National Plant Germplasm System (NPGS) is an important source for the identification of new sources of resistance. Evaluation of the NPGS sorghum collections from Ethiopia, Mali, Mozambique, and Sudan have resulted in the identification of anthracnose resistant germplasm. Evaluation of the Mali sorghum collection showed that resistant germplasm was associated with regions receiving higher amounts of rainfall. This association with weather patterns is being used to identify germplasm collection from other African countries for anthracnose evaluation. Little information is available of the genetics of resistance and evaluations are being conducted to determine the genetic diversity of resistance for the anthracnose resistant germplasm identify from these collections.
Technical Abstract: Anthracnose is one of the most damaging diseases for sorghum production. The disease can be successfully managed through the use of resistant cultivars, but the development of resistant cultivars is hindered by extensive variation in virulence within the pathogen population. Additional sources of resistance are needed to more effectively manage the disease and sorghum germplasm collections are important sources of genetic variation for anthracnose resistance. A disease inoculation procedure was developed to enhance the evaluation of anthracnose resistance for the sorghum collection maintained by the USDA-ARS National Plant Germplasm System. Germplasm evaluations have suggested that sources of anthracnose resistance could be associated with country of origin. For example, resistant germplasm was more frequently observed for the sorghum collections from Ethiopia, Mali, and Sudan. The anthracnose evaluation of the Mali germplasm collection indicated that resistance was also associated with weather patterns within Mali. Resistant germplasm was more frequently observed in regions associated with higher rainfall compared to drier regions. This association of resistance with rainfall patterns has been observed for collections from other African nations. For collections from wetter regions, such as Rwanda and Mozambique, the majority of the accessions were resistant. In comparison, nearly all the accessions in the collections from dry regions, such as Somalia and Algeria, were susceptible to anthracnose. The genetics of host plant resistance is presently being evaluated to determine if the greater frequency of resistance observed in these regions is associated with genetic variation for resistance.