Skip to main content
ARS Home » Midwest Area » Ames, Iowa » Corn Insects and Crop Genetics Research » Research » Publications at this Location » Publication #119969
Title: TROPICAL X TEMPERATE GERMPLASM RESISTANT TO CORN EARWORM (LEPIDOPTERA: NOCTUIDAE)

Author
item XU, WENWEI - TEXAS A&M
item POLLAK, LINDA
item BYNUM, JR., E - TEXAS A&M

Submitted to: Crop Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/4/2003
Publication Date: 7/3/2003
Citation: XU, W., ARCHER, T.L., BRADFORD, L., POLLAK, L.M. TROPICAL X TEMPERATE GERMPLASM RESISTANT TO CORN EARWORM (LEPIDOPTERA: NOCTUIDAE). CROP PROTECTION JOURNAL. 2003. v. 22. p. 859-864.

Interpretive Summary: Corn earworm is a major economic pest of corn both in the U.S. and other parts of the world. Chemical control is expensive and unreliable, so genetic resistance is very important. The objective of this study was to look at exotic materials from the Germplasm Enhancement of Maize Project (GEM) to see if any could contribute new genes for earworm resistance to U.S. hybrids. Many exotic populations showed promising resistance levels after two years of evaluation in Texas. There was also a relationship between the level of ear mold and earworm resistance. The results are important for breeders who will be utilizing GEM lines to develop hybrids with new and unique resistance to both ear molds and earworms.

Technical Abstract: Corn earworm, Helicoverpa zea (Boddie), is a major economic pest of corn both in the US and worldwide. The primary means of controlling corn earworm (CEW) on corn is to use resistant hybrids because chemical control is costly and inconsistent. The objective of this study was to identify new sources of CEW resistance genes from the GEM germplasm. Seventy-three GEM breeding crosses plus three check hybrids (Pioneer hybrids 3223 and 34K77 and B73 x Mo17) were evaluated in Lubbock, Texas in 1999 and 2000. The GEM crosses had either 25% or 50% tropical background. The experiment used a randomized complete block design with three replications. At maturity, 10 primary ears per plot were collected and CEW ear penetration, ear length, and grain mold were determined. Significant differences in ear penetration, ear length, ratio of ear penetration to ear length, and grain mold were found among the genotypes. Over the two years BVIR103:S04, DKXL380:S08a, DKB830:S19, GUAT209:N19, CUBA117:S15, and CUBA164:S20 had th lowest CEW damage and may be new sources of CEW resistance. DK212T:S0610, CUBA110:S0209, SCROGP3:N2017, SCROGP3:N2001, DREP150:N20, CUBA164:S2008a, DKXL212:S0915, DK212T:S0610, DKB830:S11a18, and B73 x Mo17 were most susceptible to CEW. CEW damage was positively related to grain mold. The breeding crosses with 50% tropical background had significantly lower CEW damage, less grain mold, and longer ears than those with 25% tropical background or the check hybrids.