Fusarium moniliforme, F. tabacinum, F. solani, F. semitectum, F. tricinectum,
and F. nivale, were isolated from un-sterilized and sterilized grains of the single cross
(SC-3062), double cross (DC-Dahab) and the female inbred line (FIL-X) of yellow corns.
Fusarium moniliforme was located in the most different seed parts. E ndosperm infection
with F. moniliforme was high in FIL-X comparing with SC-3062, meanwhile, the embryo
of DC-Dahab was free from the fungus. Fusarium nivale and F. solani caused highly
significant infection percentage at 17% moisture content after 45 days post infestation of
corn grains. The infections were increased significantly at 20 and 23% moisture content
and reached 100% for all tested Fusarium spp. after 45 days post infestation. Corn grains
of SC-3062 is more sensitive than DC-Dahab for infection with tested Fusarium species.
Increasing moisture content levels comparing to control increased total protein, total
carbohydrates and oil percent gradually in all infested yellow corn grains with Fusarium
spp. The highest amount of fumonisins was recorded in infested yellow corn grains
(17.1mg/g) with F. moniliforme at 23% moisture content. All fungicide treatments
significantly reduced infection % on corn grains of DC-Dahab, SC-3062 and FIL-X and
had no effect on germination % except vitavax in water reduced germination percent of
DC-Dahab and SC-3062 corn grains. As well as, exposing corn grains of hybrid DCDahab
and SC-3062 to different hot water treatments (45-70°C/5min.) had no effect on
germination % but had a great effect on infection % at the same conditions. Treating
corn grains with fungicides before storing at room temperature increased germination %
and decreased infection percentage with kernel rot pathogens. The best effective
fungicide was benlate on corn grains of SC-3062 and DC-Dahab. Treating corn grains
with fungicides before storing at 8ºC revealed a great decrease in infection percentage
with kernel rot pathogens at zero time. These decreases were clear after storage where
increasing storage periods till 90 days decreased infection % of the two hybrids (SC-3062
& DC-Dahab) and FIL-X. |
