The percentage of infection in freshly harvested grains was higher in Giza 163 cv. than Sakha 69 cv. in season 1994 but the opposite was noticed in season 1995. Grain infection was increased during storage. In 1994, applying 40 Kg N/feddan in Sakha 69, or 40 Kg N+16 Kg P/feddan in Giza 163, reduced infection in wheat grains stored for 6 months, however, 16 Kg P/feddan was quietly promising for both cvs., in 1995 season. All fertilization treatments lead to decrease aflatoxins production by Aspergillus flavus in grains of both tested cultivars. Applying 80 kg N+16 kg P20s/fed minimized the total amount of aflatoxins' in grains of Giza 163 and Sakha 69 cvs. Treatments including phosphorus showed fewer amounts of aflatoxins than those containing nitrogen alone. In Sakha 69 cv., grain infection was clearly decreased at zero time by using Fe+Mn+Cu in both seasons and Fe+Zn+Cu, Mn+Fe+Zn, and Fe+Mn+Zn+Cu in season 1995. In Giza 163 cv., grain infection at zero time was reduced by all tested treatment, except Fe+Mn+Zn+Cu, in season 1994 and Mn+Fe+Zn only in season 1995. Meanwhile, % grain infection in both wheat cvs., Sakha 69 and Giza 163, was also decreased, particularly in season 1995, by applying Fe+Mn+Cu, Fe+Zn+Cu, Mn+Fe+Zn and Fe+Mn+Zn+Cu. Among tested combinations of microelements, Fe+Mn+Cu, and Mn+Fe+Zn were the best for minimizing averages of % grain infection in both wheat cvs., during both season. Aflatoxins production by A. flavus inoculation in wheat grains stored for 6 months was decreased when growing wheat plants were sprayed once at tillering stage with any combination of the tested microelements compared to the control (plants not sprayed). Among microelements combination, Fe+Mn+Zn+Cu resulted in production of the lowest amount of total aflatoxins. Field-fungicide treatments had no significant effect on germination of stored grains. Applying ammonium sulphate at 1000 ppm gave the lowest mould infection in freshly harvested grains, however, after storage for 6 months 500 ppm of Sumisclex 50 gave the lowest infection percentage. Moisture content in freshly harvested grains was decreased with all fungicide treatments and was almost the same in both seasons. The lowest decrease in moisture content was obtained with 500 ppm of both Tecto and Sumisclex 50, after storage period. Spraying wheat plants at milk stage with any of the tested chemical treatments reduced the production of aflatoxins by A. flavus. The highest reduction was achieved by Rovral 50, while the lowest reduction was for Sportek 45%. |
