Submitted to: Cereal Research Communications
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2004
Publication Date: 12/31/2004
Citation: Li, R., Kang, M., Moreno, O., Pollak, L.M. 2004. Relationship among aspergillus flavus infection, maize weevil damage, and ear moisture loss in exotic x adapted maize. Cereal Research Communications. 32:371-378. Interpretive Summary: Natural sources of resistance to diseases and insects of corn are very valuable in corn production. Two serious disease and insect problems are kernel infection by Aspergillus flavus, which can lead to toxic Aflatoxin in food and feed, and maize weevil, which can be damaging to stored corn. A study was conducted to accumulate information on possible resistance to these pests, along with ear moisture loss, in exotic by adapted breeding crosses of corn. The objective was to determine if all traits could be handled simultaneously in a breeding program. Results suggested that all three traits were highly correlated, and that kernel infection by A. flavus would decrease when selection for maize weevil was practiced, and vice versa. Selection for decreased kernel infection and moisture loss would likely be unsuccessful when practiced simultaneously. Therefore, selection for decreased kernel infection and resistance to maize weevil could be handled in a single breeding program, but it would be more efficient to select for increased ear moisture loss separately. This research will benefit corn breeders developing genetic materials with resistance to insects and improved grain quality, and processors and consumers to have access to better quality grain because it has decreased damage from insect pests and kernel infection.
Technical Abstract: Maize (Zea mays L.) kernel infection by Aspergillus flavus and infestation by maize weevil (Sitophilus zeamais Motschulsky) remain problems in maize production and storage. This study was undertaken to evaluate 61 exotic × adapted breeding crosses obtained from the Germplasm Enhancement of Maize (GEM) project for A. flavus kernel infection rates (KIR), resistance to maize weevil damage (MWR), and ear moisture loss rate (EMLR) in 1995 and 1996, and to investigate interrelationship among them via correlation and path analyses. Highly significant correlations among the three traits were detected. A direct path effect of MWR on KIR was '0.261 (P=phenotypic) and '0.42 (G=genotypic). The direct effect of KIR on MWR was '0.276 (P) and '0.623 (G). This suggested KIR would decrease when selection is practiced for higher levels of resistance to maize weevil feeding, and vice versa. Direct path coefficient for the EMLR effect on KIR was positive at both P (0.233) and G (0.50) levels. The direct effects of KIR on EMLR were 0.25 (P) and 0.67 (G). The positive association between KIR and EMLR would be unfavorable for simultaneous selection of both traits in the desired direction. The correlation and path analyses for KIR, MWR, and EMLR provided useful information about the traits, which could be used in simultaneous selection to maximize selection gains. The KIR and MWR appeared to be the traits that could be handled in a single breeding program. From an efficiency standpoint, improvement of EMLR should be handled in a separate breeding program.