|Armstrong, John - Scott|
Submitted to: Journal of Entomological Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/12/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: The sugarcane aphid is a new invasive aphid that attacks grain and forage sorghum. We evaluated several sorghum germplasm used in breeding from the USDA-ARS Laboratory in Lubbock, TX, and found two lines that express both antibiosis and tolerance as mechanisms of resistance against the sugracane aphid. Sorghum germplasm R.11143 and R.11259 are as resistant as known sources of resistance that we previously discovered. These two sorghum lines are pollinator parents and can be used for the breeding of new sources of resistance to the sugarcane aphid.
Technical Abstract: The sugarcane aphid, Melanaphis sacchari, was discovered infesting grain sorghum near Beaumont, TX, close to the Texas and Louisiana state line a few miles inland from the Gulf coast in the late summer of 2013, and has been a perennial pest of sorghum through 2016. Our research was aimed at identifying sorghum germplasm that expresses host-plant resistance to the sugarcane aphid. We originally screened 36 lines including two known resistant sorghums (Tx2783 and DKS-37-07) and two known susceptible sources (WSH 117 and MORCH 858). From this screen, two pollinator lines (R.11143 and R.11259) developed by the USDA-ARS in Lubbock, TX, exhibited significant tolerance as indicated by damage ratings and growth characteristics such as plant height, number of leaves and chlorophyll content. R.11143 had a slight net gain in chlorophyll content for the infested compared to the non-infested plants, indicating a highly tolerant sorghum. The R.11143 and R.11259 also expressed significant levels of antibiosis where net reproduction, number of nymphs produced in a d, intrinsic rate of increase, and the reproductive period in d were all significantly lower than all entries with the exception of the known resistant controls DKS 37-07 and RTx2783. Pollinators R.11143 and R.11259 are recommended to be used in breeding programs for developing resistant sorghums threatened by the sugarcane aphid.