Interacción entre genotipos de maíz ( Zea mays L.) y dos razas del potyvirus del mosaico enanizante del maíz (MDMV)
The corn in Venezuela, like a in the rest of the world, is frequently affected by viral diseases that cause lower yields. Of all the viruses that affect corn, Maize dwarf mosaic potyvirus (MDMV) is the most important virus in the world due to the economic losses that causes in susceptible cultivars....
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2017
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| Online Access: | http://hdl.handle.net/10872/18434 |
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| Summary: | The corn in Venezuela, like a in the rest of the world, is frequently affected by viral diseases that cause lower yields. Of all the viruses that affect corn, Maize dwarf mosaic potyvirus (MDMV) is the most important virus in the world due to the economic losses that causes in susceptible cultivars.In Venezuela, two strains of this virus have been identified: MDMV-A and MDMV-V, the strain MDMV-V being the most disseminated and most severe. Currently, very little that known about the genetic basis that controls the effects of this virus. For this reason, the objective in this study was to evaluate the interaction of maize genotypes and two strains of the MDMV. Sixty S1 families derived from the hybrids Danac 255, Seminaca 176 and Dorado 5, and 18 commercial hybrids were mechanically inoculated and the disease index (IE) was used to determine the levels of host reaction. A completely randomized design with a factorial treatment arrangement was used. The interaction Family x Virus was highly significant (P <0.01). The interaction of the S1 families derived from Danac 255 and Seminaca 176 was characterized by having a greater number of susceptible genotypes to MDMV-V and resistant to MDMV-A. The S1 families derived from Dorado 5 showed a small interaction. The interactions generated in the S1 families of contrasting reactions and commercial hybrids included: families susceptible to MDMV-V and resistant to MDMV-A and intermediate to MDMV-V and resistant to MDMV-A. The distribution of the levels of resistance to MDMV -V in families derived from Danac 255 and Seminaca 176 indicated the existence of an important number of genes of small effect and cumulative action. In families derived from Dorado 5, the resistance is possibly controlled by major genes. In the case of MDMV-A, resistance could be associated with the action of major genes in great part of the families. The S1 family of contrasting reactions is an important element to know and compare the resistance levels of hybrids marketed in the country. This leads us to the need of evaluate the behavior of national and foreign hybrids subjected to certification processes. |
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