The origin of U.S. Corn Belt corn (Zea mays L.), heterotic groups, and heterotic patterns becomes less obvious with more cycles of breeding. Heterosis is poorly understood; simple curiosity cries out for more information. I endeavor to shed light on the effect of adaptedness and heterosis on U.S. Corn Belt corn. I relate pertinent happenings in the phenomenal increase in U.S. corn production. I...

Two temperate corn (Zea mays) hybrids (Pioneer 3320 and Northrup King 508), two tropical corn cultivars (Pioneer X304C hybrid and Florida SYN-1 experimental open pollinated cultivar), the sorghum (Sorghum bicolor) x sudangrass (Sorghum sudanense) hybrid DeKalb SX-17, and the sorghum hybrid DeKalb FS25E were compared for effect on nematode densities and forage yield in three plantings (one singl...

Development of corn (Zea mays L.) germplasm tolerant to water stress will be vital to sustaining corn-based farming in the U.S. Great Plains. In a companion 4-yr field study near Shelton, NE, we found that 12 hybrids displayed differential agronomic responses to varying water levels, with tolerant hybrids yielding from 27 to 42% more than susceptible hybrids under stress while yielding similarl...

Two studies were conducted at two locations to evaluate growth performance and carcass characteristics of growing-finishing pigs fed diets containing either YieldGard Rootworm corn (MON 863), a non-transgenic genetically similar corn (RX670), or two conventional nontransgenic corn hybrids (DK647 and RX740). A randomized complete block design with a 2 x 4 factorial arrangement of treatments (two...

Starch gelatinization and retrogradation properties of corn were studied to determine the effect of controlled (self) pollination versus noncontrolled pollination on analytical determinations, and the potential to eliminate the expensive and time-consuming step of self-pollinating before research screening of corn genotypes. Twenty-four hybrids were grown in two Iowa locations, Story City and A...

Spodoptera frugiperda (Smith) is a polifagous insect of major economic impact in the western hemisphere and exhibits two strains (i.e., corn and rice) that are morphologically identical but differ in ecology, genetics and physiology. In this work we identified these strains and their respective hybrids by using a PCR-RFLP of the COI gene and PCR of the tandem region FR. Moreover, we performed a...

Transgenic corn, Zea mays L., that expresses the Bacillus thuringiensis (Bt) toxin Cry1Ab is only moderately toxic to Helicoverpa zea (Boddie) and has been planted commercially since 1996. Growth and development of H. zea was monitored to determine potential changes in susceptibility to this toxin over time. Small plots of corn hybrids expressing Cry1F, Cry1F × Cry1Ab, Cry1Ab × Cry3Bb1, Cry1A.1...

Yield and ear quality of sweet corn (Zea mays L.) can be reduced by maize dwarf mosaic (MDM). When Janson and Ellett (6) first reported the disease from southern Ohio, they observed nearly total losses in fields of late-planted sweet corn. Yield reduction due to MDM and symptom expression are affected by the growth stage at which sweet corn is infected (5,12, 18,25). When late plantings of swee...