Aflatoxin in Corn before Harvest: Interaction of Hybrids and Locations¹

Abstract

Twelve corn (Zea mays L.) hybrids, including one reciprocal, with differences in trypsin inhibitor levels and insect resistance were grown during 1978 at 12 locations in the United States. The study examined the effect of planting date, inoculation with Aspergillus flavus Link ex Fr., and mechanical damage of developing kernels on aflatoxin accumulation in kernels before harvest. Although a broad occurrence of toxin was found in kernels of untreated ears from locations outside the Corn Belt, addition of A. flavus spores to silks markedly increased toxin accumulation. To a lesser extent, mechanical damage was also associated with elevated aflatoxin concert. trations. At specific locations, toxin levels varied among hybrids, but no consistent interlocation pattern of absolute toxin resistance was detected. Visual insect damage on mature ears was not linked quantitatively to toxin levels. More than 90% of the Georgia, Mississippi, Missouri, North Carolina, South Carolina, and Tennessee samples had detectable aflatoxin, but less than 30% of the samples from Illinois, Iowa, and Ohio were toxin positive. In general, bright greenish‐yellow (BGY) fluores. cence in kernels and high levels of toxin were observed, but a number of samples with low levels of toxin did not exhibit the fluorescence.

Aflatoxin Accumulation in Maize Hybrids of Different Maturities

“…The association between maturity and aflatoxin found in this study was more pronounced than other studies where a consistent relationship between aflatoxin and maturity was not observed (LaPrade and Manwiller, 1977; Lillehoj et al, 1978, 1980; Widstrom et al, 1978). The timing of the stress in these trials could be a determining factor in aflatoxin production.…”

Crop Stress and Aflatoxin Contamination: Perspectives and Prevention Strategies

“…Research supporting this concept were reported shortly thereafter Lillehoj et al 1980 ) . The data were confl icting, however, Lillehoj et al ( 1980 ) reported that an early planting had the highest amount of afl atoxin while suggested that early plantings had reduced amounts of afl atoxin in North Carolina. Comprehensive research was conducted by Widstrom et al ( 1990 ) on planting dates with data accumulated over a 5-year period.…”

“…These include: (1) planting date selection (Widstrom 1996 ) ; (2)fertilization (Wilson 1989 ) ; (3) tillage (Jones 1987 ) ; (4) irrigation (Payne et al 1986 ;Smith and Riley 1992 ) , and (5) land and hybrid selection (LaPrade and Manwiller 1976 ;Zuber 1977 ;Lillehoj et al 1982 ) , along with disease, insect, and weed management (Widstrom et al 1975 ;McMillian et al 1980 ;Lillehoj et al 1980 ;Wilson et al 1981 ;Doupnik 1972 ;Campbell et al 1993 ;Glover and Krenzer 1980 ) . Each of those factors, whether controlled or not, is inextricably linked to plant stress.…”

Identifying and developing maize germplasm with resistance to accumulation of aflatoxins

“…Plant resistance is generally considered a highly desirable strategy for reducing aflatoxin contamination in maize. Efforts to identify maize germplasm with resistance to A. flavus infection and aflatoxin contamination were initiated at several locations in the late 1970s and early 1980s (LaPrade and Manwiller, 1976;Lillehoj et al, 1976Lillehoj et al, , 1980Lillehoj et al, , 1983McMillian et al, 1982;Zuber et al, 1983). The lack of reliable field inoculation techniques, however, was a major impediment to success (Payne, 1983).…”