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United States Department of Agriculture

Agricultural Research Service

Research Project: GENETIC IMPROVEMENT OF MAIZE AND PEARL MILLET FOR RESISTANCE TO INSECTS AND AFLATOXIN Title: Evaluation of corn germplasm lines for multiple ear-colonizing insect and disease resistance

Authors
item Ni, Xinzhi
item Xu, Wenwei -
item Blanco, Michael
item Wilson, Jeffrey

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 10, 2012
Publication Date: August 1, 2012
Citation: Ni, X., Xu, W., Blanco, M.H., Wilson, J.P. 2012. Evaluation of corn germplasm lines for multiple ear-colonizing insect and disease resistance. Journal of Economic Entomology. 105:1457-1464.

Interpretive Summary: Insect and disease damage on corn ears reduces yield and imposes health threats to human and livestock by mycotoxin contaminations in the grain. Twenty germplasm lines from the Germplasm Enhancement of Maize (GEM) Program in Ames, IA, Raleigh, NC, and Lubbock, TX, were examined for insect and disease resistance in 2007 and 2008 with local resistant and susceptible controls. All of these lines are derived from exotic maize germplasm. Four types of insect damage and smut gall infection was assessed on corn ears. Corn husk tightness and extension were also examined in relation to insect damage and smut infection reduction. Significant differences in insect damage, smut infection, and husk protection traits were detected among the germplasm lines. Three of the 20 germplasm lines were identified as being multiple insect and smut resistant. Of the three best lines identified, two were derived from maize germplasm from Brazil, while the third one was derived from maize germplasm from Cuba. This study has established the baseline information to develop multiple insect and disease resistance in maize lines with good yield potential and other agronomic traits from the GEM program.

Technical Abstract: Ear-colonizing insects and diseases, which reduces yield and imposes health threats by mycotoxin contaminations in the grain, are critical impediments for corn production in the southern US states. Ten germplasm lines from the Germplasm Enhancement of Maize (GEM) Program in Ames, IA, and Raleigh, NC, and ten lines (derived from GEM germplasm) from the Texas Agricultural Experiment Station in Lubbock, TX, were examined in 2007 and 2008 with local resistant and susceptible controls. Four types of insect damage and smut disease (Ustilago maydis) infection was assessed on corn ears. Insect damage on corn ears was further separated as cob and kernel damage. Cob penetration rating was used to assess corn earworm (Helicoverpa zea) and fall armyworm (Spodoptera frugiperda) feeding on corn cobs, while kernel damage was assessed using three parameters. They were: 1) percentage of kernels discolored by stink bugs [i.e., brown stink bug (Euschistus servus), southern green stink bug (Nezara viridula), and green stink bug [Chinavia (Acrosternum) hilare]; 2) percentage of maize weevil (Sitophilus zeamais)-damaged kernels, and 3) percentage of kernels damaged by sap beetle (Carpophilus spp.), chocolate milkworm (Moodna spp.), and pink scavenger caterpillar [Pyroderces (Anatrachyntis) rileyi]. The smut infection rates on ears, tassels, and nodes were also assessed. Ear protection traits (i.e., husk tightness and extension) in relation to insect damage and smut infection were also examined. Significant differences in insect damage, smut infection, and husk protection traits were detected among the germplasm lines. Three of the 20 germplasm lines were identified as being multiple insect and smut resistant. Of the three lines, entries 5 and 7 were derived from DKXL370 developed using corn germplasm from Brazil, while entry 14 was derived from CUBA117.

Last Modified: 11/22/2014
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