Submitted to: Euphytica
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/18/2005
Publication Date: 6/30/2006
Citation: Wang, M.L., Dean, R., Erpelding, J.E., Pederson, G.A. 2006. Molecular genetic evaluation of sorghum germplasm differing in response to fungal diseases: rust (puccinia purpurea) and anthracnose (collectotrichum graminicola). Euphytica. 148:319-330 Interpretive Summary: Sorghum is the third and fifth important crop in the United States and in the world, respectively. Sorghum is well adapted to environmental extremes, such as drought. However, the value and production of sorghum crop can be reduced by major sorghum diseases. This paper focuses on two fungal diseases: rust and anthracnose. Sorghum resistant cultivars can be developed by introgression of resistance genes from sorghum germplasm, however, the resistance sources are not very clear. This hinders breeders to use genetic resources for developing cultivars which will be resistant to rust and anthracnose. To classify genetic resources for rust and anthracnose resistance, a set of DNA markers has been used. A subset of selected sorghum germplasm has been characterized and evaluated. They have been classified three clades. Each clade probably contains diffeent resistance genes. This information would be very useful for breeders to use different resistance sources to develop new cultivars which are resistant to both rust and anthracnose. This study can also help sorghum curators to establish core collections for sorghum.
Technical Abstract: To evaluate genetic diversity in relation to rust and anthracnose disease response, ninety-six accessions were randomly selected from the database of the Germplasm Research Information Network (GRIN) and characterized by a set of 40 SSR markers. The mean value of polymorphism information content (PIC) was 0.8228. Two dendrograms were generated from the molecular genetic data and field morphological data, respectively. The genetic dendrogram demonstrates that the accessions can be classified into three main clades and nine subgroups. The branched subgroups were correlated very well with the locations where the accessions were collected. Geography had significant influences on genetic similarity of sorghum germplasm. The resistance source (alleles of resistance genes and/or the resistance genes) from each clade could be different. Out of 96 accessions, only eight accessions were highly resistant to both rust and anthracnose. All the accessions from South Africa and Mali were highly resistant to anthracnose. The information from genetic classification would be useful for sorghum breeding and germplasm management.