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United States Department of Agriculture

Agricultural Research Service

Research Project: CONSERVATION, MANAGEMENT AND GENETIC ENHANCEMENT OF SORGHUM GENETIC RESOURCES AND ASSOCIATED INFORMATION

Location: Tropical Crops and Germplasm Research

Title: Assessment of genetic diversity and anthracnose disease response among Zimbabwe sorghum germplasm.

Authors
item CUEVAS, HUGO
item PROM, LOUIS
item ERPELDING, JOHN
item Brotons, Veronica -

Submitted to: Plant Breeding
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 15, 2013
Publication Date: January 14, 2014
Citation: Cuevas, H.E., Prom, L.K., Erpelding, J.E., Brotons, V. 2014. Assessment of genetic diversity and anthracnose disease response among Zimbabwe sorghum germplasm. Plant Breeding. DOI:10.1111/pbr.12133.

Interpretive Summary: The USDA-ARS National Plant Germplasm System maintains a Zimbabwe sorghum collection of 1,235 accessions from different provinces which has not been extensively employed in U.S. breeding programs due to the lack of phenotypic and genetic characterization. Therefore, 68 accessions from the Midland province of Zimbabwe were phenotyped, and evaluated for their anthracnose response for two consecutive years, and genetically characterized with 21 strategically selected simple sequence repeats markers. Results indentified new sources of anthracnose resistance that could be used in sorghum improvement breeding programs. The genetic analysis reflects that many of the resistant accessions are highly related, and were distributed into six groups, which may represent one to six different new sources of resistance. The information presented herein is valuable to conservation programs and promotes the adequate use of Zimbabwe germplasm for sorghum breeding programs.

Technical Abstract: The USDA-ARS National Plant Germplasm System maintains a Zimbabwe sorghum collection of 1,235 accessions from different provinces. This germplasm has not been extensively employed in U.S. breeding programs due to the lack of phenotypic and genetic characterization. Therefore, 68 accessions from the Midland province of Zimbabwe were phenotyped, and evaluated for their anthracnose response for two consecutive years, and genetically characterized with 21 strategically selected simple sequence repeats markers. Phenotypic analysis showed significant differences among accessions with plant height and panicle length being the most variable traits. Likewise, 25 accessions were anthracnose resistant, 9 showed variable responses, and 34 were susceptible. Genetic analysis identified 174 alleles with an average of 8.3 alleles and 11.8 genotypes per locus and a polymorphic information content of 0.60. These results reflect a moderate, genetically diverse germplasm distinctive from other reference accessions by principal coordinate analysis. Neighbor-joining clustering analysis revealed that the majority of anthracnose resistant accessions showed high genetic relatedness, therefore, this germplasm might represent one to six new sources of resistances. Results presented herein show that the Zimbabwe collection contains valuable germplasm for breeding programs and is an important source of anthracnose resistance. However, the genetic redundancy in this germplasm encourages the employment of molecular markers to reduce the size of the collection, while promoting its adequate use in sorghum breeding programs.

Last Modified: 9/10/2014
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