Location: Tropical Crops and Germplasm Research
Title: Anthracnose disease response for photoperiod-insensitive Ethiopian germplasm from the U.S. sorghum collection Author
Submitted to: World Journal of Agricultural Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 31, 2009
Publication Date: November 15, 2009
Citation: Erpelding, J.E. 2009. Anthracnose disease response for photoperiod-insensitive Ethiopian germplasm from the U.S. sorghum collection. World Journal of Agricultural Sciences. 5(6):707-713. Interpretive Summary: Ethiopia is an important center of genetic diversity for sorghum and 7,232 germplasm accessions from Ethiopia are maintained by USDA-ARS, National Plant Germplasm System. The majority of the sorghum germplasm from Ethiopia is sensitive to day length and will not flower when planted during the summer in the United States. However, 180 of these accessions are less sensitive to day length and will flower during the summer months. These accessions are a useful source of genetic variation for sorghum improvement and may also be a source of genetic diversity for disease resistance. Anthracnose is one of the most important fungal diseases of sorghum and the 180 accessions were evaluated for anthracnose resistance at the USDA-ARS, Tropical Agriculture Research Station research farm in Isabela, Puerto Rico during the 2008 and 2009 growing seasons. The frequency of accessions showing resistance was low with only 19% of the accessions rated as resistant across the two growing seasons. However, the 35 anthracnose resistant accessions showed variation for other traits and could also provide genetic variation for host-plant resistance.
Technical Abstract: Ethiopia is an important center of genetic diversity for sorghum germplasm; however, photoperiod-sensitivity limits the utilization of this genetic resource. The United States National Plant Germplasm System maintains 180 Ethiopian sorghum accessions that are less sensitive to photoperiod and these accessions were inoculated with Colletotrichum sublineolum and evaluated for disease resistance at the Tropical Agriculture Research Station in Isabela, Puerto Rico during the 2008 and 2009 growing seasons. Disease response was similar across growing seasons, with 35 accessions rated as resistant and 98 accessions showing a susceptible response to anthracnose. Variation for disease resistance across growing seasons and replications was observed for 47 accessions and these accessions also showed low mean infection severity. Eighteen accessions showed a highly susceptible response across growing seasons with plant death before maturity observed for nine accessions. Disease severity was also similar for the two growing seasons with a mean infection severity of 23.4% for the 136 accessions rated as susceptible in 2008 and 22.6% for the 140 accessions rated as susceptible in 2009. Although the frequency of anthracnose resistant accessions was low for this germplasm subset, the collection showed phenotypic diversity suggesting possible genetic variation for anthracnose resistance that would be beneficial for sorghum improvement.