Transgenic Bt corn hybrids have been available for more than 10 years and are known to control specific insects. More recently, so-called “stacked-gene” hybrids, have been released with multiple insect resistance ge...Transgenic Bt corn hybrids have been available for more than 10 years and are known to control specific insects. More recently, so-called “stacked-gene” hybrids, have been released with multiple insect resistance genes and genes for herbicide resistance, resulting in up to 6 traits per plant. Because insect damage can lead to increased levels of mycotoxins, such as aflatoxins and fumonisin, we designed a study to compare ten commercially available corn hybrids, two non-transgenic, four with both herbicide and insect tolerance (stacked-gene) and four with glyphosate tolerance only to determine if any hybrid class had the advantage of reduced mycotoxin contamination. The experiment was carried out in the Mississippi State University Delta Research Extension fields in Stoneville, MS for two years in fine sandy loam and clay soil. Rows were either inoculated at the V10 stage of growth with toxigenic Aspergillus flavus K54 (NRRL 58987, isolated from corn kernels in Mississippi), grown on wheat, and applied at a rate of 22.42 kg/ha or allowed to become naturally infected with disease-producing fungi, including various Fusarium and other Aspergillus spp. Mycotoxin production differed according to the soil type with lower levels detected in the hybrids planted in clay soil vs. sandy soil. However, no significant differences in mycotoxin production were found amongst the hybrid classes. More research is needed to identify conditions under which transgenic hybrids might produce higher yields and lower mycotoxin levels. Presently, selection of transgenic hybrids will not replace integrated strategies of biocontrol, host plant resistance, or good crop management practices for achieving adequate mycotoxin control in corn.展开更多
The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic ...The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic breeding,physiology and pathology in this paper.Then the countermeasures to prevent the danger from disease of B. maydis in CMS hybrid pro-duction were proposed.展开更多
Mycotoxigenic fungi and mycotoxins in 3 inbred lines (hybrids resistant to corn ear rot) were identified in twenty samples. The maize (Zea mays) accessions were collected in five plots of two municipalities in High Va...Mycotoxigenic fungi and mycotoxins in 3 inbred lines (hybrids resistant to corn ear rot) were identified in twenty samples. The maize (Zea mays) accessions were collected in five plots of two municipalities in High Valley, state of Hidalgo. The fungal population was determined with a microbiological dilution method used two culture media (PDA and ELA), for the detection of mycotoxins with thin layer chromatography with visual inspection in UV light and a direct competitive enzyme-linked immunosorbent (ELISA). The results showed high moisture content in all hybrids evaluated on an average of 38.3% and a 1.8 × 10<sup>3</sup> UFC/g fungus, values within the permitted limits by the Mexican legislation;however the most prevalent fungi were Fusarium sp. (76%), Alternaria sp. (14%), Penicillium sp. (4%) and Aspergillus sp. (5%), and the species Aspergillus nidulas, Aspergillus flavus, Fusarium verticillioides, Fusarium poae, and Penicillium ochraceum. The aflatoxin concentration was observed in a range from 2 to 13 ng/g and 370 to 660 ng/g to fumonisins. It is concluded that trilinear corn hybrids have a variety of pathogenic potential fungi. The two genetic hybrids showed levels of aflatoxins and fumonisin safe for human consumption, contrary to one hybrid, with a content not suitable for human consumption. A better understanding of genetic hybrids corn will improve predictive mycotoxin contamination.展开更多
文摘Transgenic Bt corn hybrids have been available for more than 10 years and are known to control specific insects. More recently, so-called “stacked-gene” hybrids, have been released with multiple insect resistance genes and genes for herbicide resistance, resulting in up to 6 traits per plant. Because insect damage can lead to increased levels of mycotoxins, such as aflatoxins and fumonisin, we designed a study to compare ten commercially available corn hybrids, two non-transgenic, four with both herbicide and insect tolerance (stacked-gene) and four with glyphosate tolerance only to determine if any hybrid class had the advantage of reduced mycotoxin contamination. The experiment was carried out in the Mississippi State University Delta Research Extension fields in Stoneville, MS for two years in fine sandy loam and clay soil. Rows were either inoculated at the V10 stage of growth with toxigenic Aspergillus flavus K54 (NRRL 58987, isolated from corn kernels in Mississippi), grown on wheat, and applied at a rate of 22.42 kg/ha or allowed to become naturally infected with disease-producing fungi, including various Fusarium and other Aspergillus spp. Mycotoxin production differed according to the soil type with lower levels detected in the hybrids planted in clay soil vs. sandy soil. However, no significant differences in mycotoxin production were found amongst the hybrid classes. More research is needed to identify conditions under which transgenic hybrids might produce higher yields and lower mycotoxin levels. Presently, selection of transgenic hybrids will not replace integrated strategies of biocontrol, host plant resistance, or good crop management practices for achieving adequate mycotoxin control in corn.
文摘The abortive behaviour and the cytoplasm quality of cytoplasmic male-sterility(CMS)lines of homocaryon were investigated and the existence of C race of Bipolaris maydiswere discussed from the point of view of genetic breeding,physiology and pathology in this paper.Then the countermeasures to prevent the danger from disease of B. maydis in CMS hybrid pro-duction were proposed.
文摘Mycotoxigenic fungi and mycotoxins in 3 inbred lines (hybrids resistant to corn ear rot) were identified in twenty samples. The maize (Zea mays) accessions were collected in five plots of two municipalities in High Valley, state of Hidalgo. The fungal population was determined with a microbiological dilution method used two culture media (PDA and ELA), for the detection of mycotoxins with thin layer chromatography with visual inspection in UV light and a direct competitive enzyme-linked immunosorbent (ELISA). The results showed high moisture content in all hybrids evaluated on an average of 38.3% and a 1.8 × 10<sup>3</sup> UFC/g fungus, values within the permitted limits by the Mexican legislation;however the most prevalent fungi were Fusarium sp. (76%), Alternaria sp. (14%), Penicillium sp. (4%) and Aspergillus sp. (5%), and the species Aspergillus nidulas, Aspergillus flavus, Fusarium verticillioides, Fusarium poae, and Penicillium ochraceum. The aflatoxin concentration was observed in a range from 2 to 13 ng/g and 370 to 660 ng/g to fumonisins. It is concluded that trilinear corn hybrids have a variety of pathogenic potential fungi. The two genetic hybrids showed levels of aflatoxins and fumonisin safe for human consumption, contrary to one hybrid, with a content not suitable for human consumption. A better understanding of genetic hybrids corn will improve predictive mycotoxin contamination.
