Location: Crop Genetics and Breeding ResearchTitle: The sorghum epicuticular wax locus Bloomless2 reduces plant damage in P898012 caused by the sugarcane aphid
|PUNNURI, SOMASHEKHAR - Fort Valley State University|
|Knoll, Joseph - Joe|
Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2019
Publication Date: 4/3/2020
Citation: Harris-Shultz, K.R., Punnuri, S., Knoll, J.E., Ni, X., Wang, H. 2020. The sorghum epicuticular wax locus Bloomless2 reduces plant damage in P898012 caused by the sugarcane aphid. Agrosystems, Geosciences & Environment. 3:e20008. https://doi.org/10.1002/agg2.20008.
Interpretive Summary: Sugarcane aphids have become the major pest on sorghum since their first detection near Beaumont, Texas in 2013. Since 2013, sugarcane aphids have spread to all sorghum growing regions in the United States. Sugarcane aphids are currently managed by the combined use of seed treatments, use of hybrids with host resistance, and chemical control. Previous studies have shown that bloomless (lacking visible wax on the aerial part of the plant) and near bloomless sorghums have resistance to greenbug biotypes C and E (greenbugs are aphids). To determine if the bloomless phenotype can confer resistance to sugarcane aphids, five sorghum mutants in the Bloomless2 locus, and their wildtype parents (P898012, Tx7078, P954035) were obtained and tested for aphid resistance in greenhouse and field tests. Aphid-induced plant damage was consistently greater for the mutants in the P898012 background than the wildtype parent. Thus, the Bloomless2 locus reduces aphid-induced plant damage in the P898012 background but has a limited role in the Tx7078 and P954035 backgrounds. These results suggest the effect of the Bloomless2 locus on plant damage caused by sugarcane aphids may be cultivar dependent.
Technical Abstract: The sugarcane aphid [Melanaphis sacchari (Zehntner)] has been rapidly spreading in the southern United States with devastating impacts on sorghum [Sorghum bicolor (L.) Moench]. Previous studies have shown the sorghum epicuticular wax mutants, in particular a bloomless2 (bm2) mutant and a sparse bloom mutant, are resistant to greenbugs [Schizaphis graminum (Rondani)], a type of aphid. In this study we sought to determine if five different genotypes, which all have mutations in the Bm2 locus, have increased resistance or susceptibility to sugarcane aphids as compared to their respective wild-type plants (P954035, P8908012, and Tx7078). Two greenhouse studies with artificial infestation and one field study under natural infestation were conducted. Aphid numbers on the second leaf from the top and the lowest green leaf, plant damage score, and plant growth stage were assessed at weekly intervals. The Greenhouse Test 2 and the Field test were the most effective at determining plant resistance and susceptibility. Bm2 mutants of P898012 had greater plant damage than P898012. This suggests that the Bm2 locus has a role in reducing aphid induced plant damage in the P898012 background yet has a limited role in the Tx7078 and P954035 backgrounds.