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The aim of the present study was to examine whether the induction of maize microspore embryogenesis could be triggered by the application of biogenic alcohols, as was reported earlier in wheat. A single cross hybrid (A 18) raised in the phytotron was used as anther donor for shed microspore cultures after cold pretreatment. At the onset of culturing, anthers in liquid YP medium were treated with 0.2 or 0.4% n-butanol or with 2 mM aminoethanol (2-AE) for 6 or 18 hours.The treatments caused a drastic (approx. 50%) decrease in the viability of the microspores. After a few days of culture in medium containing neither n-butanol nor 2-AE, 9-13% of the microspores remained alive and capable of switching to the sporophytic pathway of development.Treatment with 0.2% n-butanol for 6 h considerably increased the frequency of symmetric nuclear divisions (more than 3×) and of induced microspores (2×). The embryo yield was also elevated by 10%. The results showed that n-butanol could be used to improve the androgenic response and microspore embryogenesis in maize, but not as efficiently as in wheat. Further examination will be required to find the reasons for the different behaviour of microspores of the two species.

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The chilling tolerance of doubled haploid (DH) maize plants selected and regenerated from microspores exposed to prooxidants, paraquat or tert-butyl hydroperoxide was determined by monitoring cold-induced changes in the photosynthetic electron transport, CO2 assimilation processes and chlorophyll breakdown in young leaves after cold treatment (8°C for 5 days). The results were compared to those of the non-selected DH line and the original hybrid plants. Chilling stress caused a great reduction in the Fv/Fm, qP and ΔF/Fm’ fluorescence parameters, related to the photosynthetic electron transport processes, and in carbon assimilation, and resulted in chlorophyll breakdown. These changes were less extensive in the selected DH plants, which showed elevated antioxidant capacity both at ambient and at low temperature. Among the antioxidant enzymes tested, the activity of GR and GST was induced by chilling stress to the greatest extent. Correlations between cold-induced changes in the photosynthetic apparatus and the antioxidant capacity of the plants suggested that the better protection against oxidative stress induced by the elevated antioxidant capacity of the plants contributed to protecting the photosynthetic apparatus from cold.

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Acta Agronomica Hungarica
Authors: L. Sági, M. Rakszegi, T. Spitkó, K. Mészáros, B. Németh-Kisgyörgy, A. Soltész, F. Szira, H. Ambrus, A. Mészáros, G. Galiba, A. Vágújfalvi, B. Barnabás, and L. Marton

Research with transgenic plants in the Agricultural Research Institute of the Hungarian Academy of Sciences is primarily related to applications that are essential for the genetic improvement of cereals. The two main directions are connected to wheat and maize breeding and are focused on improving agronomic and nutritional traits. This paper highlights experiments in these areas, which are conducted in national as well as international collaborations. The transparency of this work is ensured by the dissemination of information about approved confined field tests to the public via the internet.

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