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In the course of gene bank research, problems frequently arise when valuable genetic materials have to be multiplied in an environment where the climatic conditions are quite different from those in its original habitat. In recently commenced experiments on the raising of emmer, the heading dates of two genotypes originating from different sources (MvGB 301 and MvGB 304) were investigated in a gradient growth chamber in the Martonvásár phytotron. This chamber allows precise information on the optimum temperature and light requirements of plants in different developmental stages to be obtained during the growth of a single generation. The data indicated that MvGB 301 headed considerably later than MvGB 304 at all temperature levels, but both varieties headed normally even at a constant very low temperature of 8°C. It was found that the light intensity had no influence on the heading dates of the two varieties.

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As a consequence of the recent spread of organic crop production, there is an increasing demand on the market for foodstuffs and food raw materials of special quality. New interest is being evinced in old cereal species that have been ignored for a long period, such as einkorn and emmer. Their production is hindered, however, by the fact that no breeding has been carried out on these species for long decades, and the landraces currently available are not suited to modern cultivation conditions. The breeding of varieties with the required habit is hindered by the lack of information on the plant structure of the various landraces and on the environmental dependence and inheritance of the characters that determine plant structure. Earlier studies suggest that inhomogeneous environmental systems can be used to identify the temperature and light conditions under which the phenotypic differences responsible for plant structure are the greatest, thus allowing the inheritance of these traits to be investigated. When two emmer landraces originating from diverse climatic regions (MvGB 301 and MvGB 304) were grown in a gradient phytotron chamber, it was found that relatively higher temperatures were more suitable for pinpointing differences in plant height, as the difference between the two varieties decreased parallel to a drop in temperature. Within the temperature range investigated it is advisable to choose the taller variety as basic breeding stock for organic variety development, as its height is closer to the ideotype for organic varieties. The length of the last internode in MvGB 301 is independent of changes in temperature, indicating that the phenotype is stable for this trait. The results clearly demonstrate that it is possible to find types of emmer which are morphologically adapted to the requirements of organic farming and have a plant structure relatively little affected by the genotype × environment interaction.

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The multiplication and characterisation of genetic stocks originating under very different ecological conditions is a problem constantly encountered in gene bank research. However, the major components of the original environment, such as temperature, light and humidity, can be reproduced under artificial conditions in the phytotron. The gradient, or inhomogeneous, chamber available in the phytotron of the Agricultural Research Institute of the Hungarian Academy of Sciences, Martonvásár, makes it possible to elaborate plant growth programmes optimised for the various developmental phases of each population in a single step. In this chamber gradients of two extremely important environmental factors, temperature and illumination, can be simultaneously programmed, thus allowing the optimum light × heat combinations to be identified. However, the use of complete inhomogeneity (light × heat) makes it extremely difficult to evaluate the experimental results, since biometric methods based on traditional statistics are unable to handle this situation. It is thus essential to find a method suitable for the comparative analysis of continual variables (Okada et al., 2000). The present paper reports on the first phase in the development of a plant growth programme for emmer, based on investigations made on two gene bank accessions of winter Triticum turgidum ssp. dicoccon (Schrank) Thell. (MvGB 301 and MvGB 304). In the gradient chamber study the accumulation of dry biomass in three-week-old plants was investigated as a function of temperature and light intensity. The results suggest that a temperature of 10-12°C combined with low or moderate light intensity is optimum for the germination and initial development (0-4 weeks) of emmer. These conditions also induced good tillering, which is extremely important, especially for gene bank accessions where the possibility of seed multiplication and field cultivation is limited.

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In order to evaluate the effect of light intensity and photoperiod on heading and to establish the reaction types of barley, a set of barley germplasm of various geographical origin and growth habit was examined in a series of controlled growth chamber experiments combining two levels of light intensity with long and short photoperiod regimes. Low light intensity contributed only a limited portion to the total variance of heading and this originated to a large extent from the genotype × light intensity interaction for both photoperiods. Under the long photoperiod regime the effect of low light intensity was only apparent in a significant delay in heading. Under a short photoperiod the type of sensitivity depended on the growth habit. Low light intensity hastened plant development in 15% of the spring barley varieties, while the flowering of 44% of the winter barley varieties was significantly delayed. Establishing the reaction types for photoperiod and low light intensity in this range of barley germplasm made it possible to identify the typical reaction types of the two growth-habit groups. In addition, it also became possible to identify genotypes with contrasting or unusual combinations of these traits.

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The early growth and tillering capacity of two barley (Hordeum vulgare L.) varieties (Dicktoo and Kompolti Korai) were investigated in a gradient growth chamber. The identification of these crop traits is important under organic agricultural conditions in the selection of new varieties for competitiveness against weeds. The results clearly demonstrate that the initial development of the two barley varieties depended considerably on the plant growth conditions. The temperature gradient was found to have the greater effect during early development, causing significant differences in all the traits at all measurement dates. The results indicate that the two varieties differ substantially for two characteristics important for organic farming. As regards tillering ability, Dicktoo appears to be the more desirable type, despite the fact that it is unable to achieve its tillering potential at higher temperatures. Under certain ecological conditions, the relative temperature insensitivity of Kompolti Korai could be an advantage. As far as early development vigour is concerned, Kompolti Korai is clearly a desirable type for organic farming, since it produced rapidly growing, robust plants in all the temperature ranges. From the point of view of organic breeding, a combination of the valuable traits of these two varieties could be the way forward.

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The effect of CO2 enrichment on the rate of photosynthesis and the water use efficiency (WUE) of young pepper and tomato plants was studied in the phytotron. A CO2 level of 1000 ppm significantly increased the net assimilation rate in the upper foliage, while the increase was even more considerable in the lower layers of the canopy, with values of up to 100%. The 1500 ppm CO2 level caused a further substantial increase in CO2 assimilation and at least doubled (in tomato) or tripled (in pepper) the water use efficiency on a leaf area basis compared to the ambient values. Although the response in terms of photosynthesis and WUE was not variety-specific, there were differences between the pepper hybrids in the biomass components, exceeding 100% for the total biomass at the 1500 ppm CO2 level. In tomato, however, there was no significant variation in the total biomass of the three hybrids investigated in this early phase of development at either CO2 level.

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Acta Biologica Hungarica
Authors: Ildikó Karsai, B. Kőszegi, G. Kovács, P. Szűcs, Klára Mészáros, Z. Bedő, and O. Veisz

In order to analyse the effects of temperature (9–22 °C) and light intensity (170–576 μmol m −2 s −1 ) on plant development two barley varieties with contrasting seasonal growth habits were included in a series of experiments consisting of controlled environment tests. The effect of constant (18 °C) and daily fluctuating (18/16 °C) temperature with a long photoperiod was also examined in a set of barley varieties including winter, facultative and spring barleys. Dicktoo with facultative growth habit was more sensitive to unfavourable conditions than Kompolti korai with winter growth habit; the flowering of Dicktoo was significantly delayed by sub-and supra-optimal temperatures and low light intensity accompanied by higher or fluctuating temperatures. The optimal temperature at flowering was also significantly lower for Dicktoo than for Kompolti korai (16.0 °C vs. 21.0 °C, respectively). Plant development was the fastest when there was no fluctuating environmental factor in the growing conditions and was significantly delayed with application of photo cycle. The addition of thermo cycle to photo cycle had an even stronger delaying effect. Facultative barleys were the most sensitive, followed by winter barleys, while spring barleys the least sensitive to the introduction of thermo cycle.

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Acta Agronomica Hungarica, 48(3), pp. 227–236 (2000) OCCURRENCE OF THE 1RS/1BL WHEAT–RYE TRANSLOCATION IN HUNGARIAN WHEAT VARIETIES B. K Ő SZEGI, G. LINC, A. JUHÁSZ, L. LÁNG and M. MOLNÁR-LÁNG AGRICULTURAL RESEARCH INSTITUTE OF THE HUNGARIAN ACADEMY OF SCIENCES, MARTONVÁSÁR, HUNGARY Received: August 15, 2000; accepted: October 15, 2000 The translocation which involves the substitution of the short arm of the 1R rye chromosome for the short arm of the 1B wheat chromosome by means of centric fusion has exercised an enormous influence on the world’s wheat breeding. Since the first mention of this translocation in 1937 the incidence of the 1RS/1BL translocation has been reported in connection with several hundred wheat varieties. Varieties carrying the translocation possess a chromosome segment which includes the resistance genes Sr31 (stem rust, Puccinia graminis), Lr26 (leaf rust, P. recondita), Yr9 (yellow rust, P. striiformis), Pm8 (powdery mildew, Erysiphe graminis) and Gb (aphid, Schizaphis graminum). The present paper investigates the occurrence of the 1RS/1BL translocation in wheat varieties bred in Hungary in recent years. It was found that 35 (53%) of the 66 Hungarian-bred wheat varieties registered in Hungary between 1978 and 1999 carried the 1RS/1BL translocation.

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