ARS | Publication request: CHARACTERIZATION OF GEM CORN GERMPLASM FOR CORN EARWORM RESISTANCE

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: October 28, 2000
Publication Date: N/A

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 germplasm breeding crosses plus four check hybrids (Pioneer hybrids 3223 and 34K77, B73 x Mo17, CK4) 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 ears per plot were harvested and data were collected on ear feeding rating, ear length, and grain mold. Significant differences in CEW ear feeding, ear length, ratio of ear feeding over ear length and grain mold were found among the entries. On the average over two years, BVIR103:S04, DKXL380:S08a, DKB830:S19, GUAT209:N19, CUBA117:S15, and CUBA164:S20 had the lowest CEW damages and may potentially contribute new sources of CEW resistance. On the contrary, 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. The CEW damage was positively related to grain mold. The breeding crosses with 50% tropical backgroud had significantly lower CEW damages, less grain mold, and longer ears than those with 25% tropical background and the check hybrids.