AGRICULTURAL RESEARCH INSTITUTE OF THE HUNGARIAN ACADEMY OF SCIENCES
Brunszvik u. 2, H-2462, Martonvásár, Hungary.
In autumn 1999, wheat was again sown on more than a million hectares. Sowing conditions were optimum, emergence rapid, and the wheat stands were in fine condition. The plants overwintered well and repeated flooding in a number of places caused considerable damage. The rainy weather was followed from mid-April until harvest by drought and heat. In May, the daily maximum temperature was often over 30°C and rose to 35-36°C in early June. The varieties headed 12-14 days earlier than usual. Because of the drought, no serious epidemics occurred, there was no grain shrivelling, and a moderate yield was achieved (3.62 t/ha).
Z. Bedö, L. Szunics, L. Láng, Lu. Szunics, O. Veisz, I. Karsai, A. Juhász, M. Rakszegi, Gy. Vida, and P. Szücs.
Six, early maturing, Martonvásár-bred winter wheat varieties were registered in 2000.
Mv Emese (Mv 106-97) is an extra-early maturing, hard red, awned wheat (pedigree: MvMA/Mv12//F2098). Mv Emese is characterized by very good baking quality, excellent frost and lodging resistance, good resistance to powdery mildew, and moderate resistance to leaf rust and stem rust.
Mv Mariska (Mv 119-97) is an extra-early, hard red wheat variety. The variety, selected from the cross 'Delta/Spartanka//Mv19' and has good rheological characteristics. Mv Mariska is frost resistant, has good lodging resistance, is moderately resistant to powdery mildew and stem rust, and moderately susceptible to leaf rust.
Mv Dalma (Mv 108-97) is a very early, hard red variety (pedigree: GK-Szeged/Mv8//Balkan/3/F2098/4/F2076). The baking quality is outstanding. Mv Dalma is resistant to stem rust, moderately resistant to leaf rust and powdery mildew, and has excellent frost resistance. The variety carries the T1A·1R wheat-rye translocation.
Mv Palotas (Mv 107-97) is an early, hard red, quality wheat (pedigree: MvMa/Mv8//F2098) with a wet-gluten content of 32-37 % and a farinograph quality of A1. Mv Palotas is the earliest and best yielding wheat in Hungary for improving flour quality, has good field resistance to leaf rust and powdery mildew, and is resistant to stem rust.
Mv Prizma (Mv 204-97) is an early wheat of good rheological quality and average protein content selected from the cross 'Fatima/Mv8'. Mv Prizma is resistant to stem rust and moderately susceptible to leaf rust and powdery mildew. The variety has the T1B·1R wheat-rye translocation.
Mv Matild (Mv 235-97) is an early, winter-hardy wheat with medium quality. Mv Matild is moderately susceptible to leaf rust and powdery mildew. The pedigree of Mv Matild is 'GK-Zombor/F130L11//F2076'.
Despite its good functional properties, the variety Bánkúti 1201 has been found to have a 2+12 or 3+12 allele composition on chromosome 1D. In order to determine the reason for its quality traits, a gene-specific PCR technique was applied in preliminary experiments to examine the HMW-glutenin allele composition of Bánkúti. In the course of the analysis, a fragment characteristic of Bánkúti 1201 was identified and the nucleotide order determined by sequencing. A 1Ax2* gene variant, which despite near homology differed from the original 1Ax2* gene at one important point was found. At 1,181 bp of the 1Ax2* sequence, nucleotide exchange was observed in the middle nucleotide of the TCTTGT base triplet, involving the exchange of serine for cysteine. The gene was designated 1Ax2*B. The presence of an extra sulphydryl group, like that of the extra cysteine in the 1Dx5 gene, facilitates the formation of further disulphide bonds, leading to an improvement in gluten quality characters.
The Australian bread wheat line L88-6 was transformed at IACR-Rothamsted, Harpenden, UK (Barro et al. 1997) in order to improve the functional properties of the flour. The transgenic B73-6-1 spring wheat line contains extra copies of a native HMW-glutenin gene (1Dx5). The technological and rheological properties of these two lines were studied in a field experiment. The transgenic line B73-6-1 had a higher protein content than the control line L88-6, as measured by the Kjeldahl method with a Perten Inframatic 8611 instrument. The higher protein content of the transgenic line could be related to the lower seed weight compared with the control line. B73-6-1 also had higher wet gluten content (NIR), kernel hardness, Zeleny, and SDS values and a greater RMT than the nontransformed control line L88-6. To determine the functional properties of the grain, a 10-g Mixograph was used. B73-6-1 showed higher dough-development time, but all the other parameters were lower. The flour from B73-6-1 initially hydrated but then failed to develop properly during dough mixing, whereas L88-6 behaved as a normal wheat cultivar. The Chopin Alveograph demonstrated the deficiency of dough extensibility and elasticity of B73-6-1. The field experiment gave us the possibility to test the transgenic wheat under Central European conditions and to use higher amounts of flour for testing, closer to commercial use. Our results support those of Rooke et al. (1999) that the over expression of subunit 1Dx5 results in an extra strong type of dough suitable for blending with poor grade flour or for the development of novel end uses.
The infection of genotypes carrying known leaf and stem rust resistance genes was studied in artificially inoculated nurseries. We found that the resistance genes Lr9, Lr19, Lr24, Lr25, and Lr29 provided complete protection against leaf rust in 2000. The infection of NILs with the genes Lr12, Lr17, Lr23, Lr28, Lr35, Lr37, and Lr 38 was 10 % or less. The virulence to genes Lr18, Lr21, Lr32, Lr34, and LrW, which were previously efficient, increased compared to earlier years. Varieties with genes Sr7a, Sr9b, Sr11, Sr30, Sr31, Sr36, Sr37, SrDr+1, and SrGT were infected the least with stem rust.
When considering the possibility of using MAS, varieties and breeding lines of Martonvásár origin were tested with RAPD primers for the presence of the resistance genes Lr9, Lr24, and Lr35. The genotypes examined do not have these resistance genes. New combinations were developed where one of the parents was a Martonvásár variety and the other a genotype with a known resistance gene traceable using markers.
The race composition and degree of virulence of the natural powdery mildew population found in the neighborhood of Martonvásár, and the efficiency of known resistance genes were studied under controlled conditions in the greenhouse. The dominant races of wheat powdery mildew (and their frequency) in 2000 were 90 (22.23 %), 51 (13.89%), 72 (12.97 %), 59 (10.19 %), and 70 (9.26 %). The number of virulence genes in the pathogen population averaged 5.07. Satisfactory protection from the wheat powdery mildew pathotypes identified was provided by the resistance genes Pm4a (Khapli), Pm1+2+9, Pm2+Mld, Pm4b+, and Pm4a+.
Head blight resistance of 183 T. aestivum and 34 T. durum varieties and breeding lines and of 36 foreign sources of resistance was tested in an irrigated experiment with artificial inoculation to ensure high pathogen pressure. The intensity of infection was evaluated in the field and in the laboratory (spike infection, changes in grain mass, visible grain infection and infection appearing during germination). As the result of infection, there was a reduction in both the hectoliter and thousand grain masses of the samples. In the course of visual scoring the degree of infection was found to be under 10 % for 57 genotypes, but this was only true of seven genotypes in the germination test. Among the resistance sources were Sumai 3, Frontana, Nobeokabozukomugi, and '80456/Yangmai 5'. Among the Martonvásár lines, Mv 233-98 was found to have outstanding resistance.
We studies changes in the components of the antioxidant-defence system, which provides protection against the damaging effect of oxygen-containing free radicals and of molecules in a state of excitation. Under stress conditions, including frost, the effect of cold hardening was studied by determining the activity of the enzymes glutathione reductase (GR), catalase (Cat), ascorbate peroxidase (APx), guaiacol peroxidase (GPx), and glutathione-S-transferase (GST). Higher activity was observed in the leaves of hardened plants in the case of APx, GPx, GR, and GST, whereas catalase activity was higher in the control. In the tillering node, no significant difference was found between the control and hardened plants. A correlation was demonstrated in hardened leaves between the activities of Cat, Apx, and GPx and frost resistance; varieties with better frost resistance had higher enzyme activity.
The initial development of cereals is better when the atmospheric CO2 concentration is increased. The leaf area and green mass are greater in all the varieties than in plants grown under normal conditions, but the magnitude of this difference varies for each species and variety. The plant response to changes in one component of the environment, the CO2 quantity, confirm earlier observations indicating that triticale and rye have good tolerance.
The joint effect of rises in atmospheric CO2 concentration and temperature were investigated on the grain yield and quality of wheat. In this series of experiments, the higher (750 µmol/mol) atmospheric CO2 concentration again increased the grain yield of wheat, and compared with the average this increase was significant at the 0.1 % level for two varieties (Mv Martina and Mv Emma) and at the 1 % level for Mv Mezöföld.
Protein content, which is of fundamental importance for wheat quality and is influenced to a considerable effect by environmental factors, changed to a great extent due to the rise in CO2 concentration. Doubling the level of CO2 concentration had an unfavorable effect on the protein content. For varieties with excellent quality (Mv Emma and Mv Mezöföld), the protein content was low, at the 0.1 % probability level both at normal and higher temperatures. High temperature at ripening (heat shock) increased the protein content compared with the dry matter %. This change was significant at the 0.1 % level for all three varieties.
Research in the phytotron proved numerically the yield-modifying effect of the changes expected in the major environmental factors as the result of climatic changes. Within certain limits, the positive effect of increasing atmospheric CO2 concentration counterbalances the yield-reducing effect of higher temperatures and of the drought arising due to the lower rainfall. As a consequence of changes in the frequency of extreme climatic conditions, this effect is not always manifested. Among the genotypes examined, considerable differences were observed for drought and heat tolerance and for CO2 utilization. Thus, breeding could be done for these traits in order to develop varieties with excellent adaptability.
J. Sutka, G. Galiba, M. Molnár-Láng, G. Kocsy, J. Jakab, G. Kovács, G. Linc, A. Vágújfalvi, E. D. Nagy, A. Bálint, and B. Tóth.
Salt and osmotic stress. The effect of drought and salt stresses on the water-soluble carbohydrate content in wheat seedlings was examined to characterize the involvement of major sugar components in the adaptive processes. Hydroponically grown seedlings of four wheat varieties differing in drought and salt tolerance were exposed to consecutive water (polyethylene glycol, PEG) and salinity (NaCl) stresses. The total water-soluble carbohydrate (WSC), glucose, fructose, sucrose, and fructan contents of stems (nonphotosynthetic tissue) were determined. Tolerant genotypes accumulated more soluble carbohydrate than did sensitive ones. Both ionic and nonionic stresses increased the concentration of reducing sugars, sucrose and fructans. Drought-tolerant varieties accumulated sucrose to a significantly greater level than did sensitive ones under nonionic stress conditions. Changes in the fructan content of plants after transfer from PEG to NaCl solutions were genotype dependent, increasing in salt-tolerant and decreasing in salt-sensitive cultivars. These results indicate that WSC might be a useful marker for selecting genotypes that are more drought or salt tolerant. The type of sugar comprising the increase in WSC appears to be a less reliable marker, because the initial response was an increase in monosaccharides and the delayed response was an increase in fructan.
A genetic study of frost tolerance. Although cold acclimation in cereals involves the expression of many cold-regulated genes, genetic studies have shown that only very few chromosomal regions have loci that play an important role in frost tolerance. To investigate the genetic relationship between frost tolerance and the expression of cold-regulated genes, the expression and regulation of the wheat homologue of the barley cold-regulated gene cor14b was studied at various temperatures in frost-sensitive and frost-tolerant wheat genotypes. At 18/15°C (day/night) temperatures frost-tolerant plants accumulated cor14bd mRNAs and expressed COR14b proteins, whereas sensitive plants did not. This result indicates that the threshold temperature for the induction of the wheat cor14b homologue is higher in frost-resistant plants and allowed us to use this polymorphism in a mapping approach. Studies made with chromosome substitution lines showed that the polymorphism for the threshold induction temperature of the wheat cor14b homologue is controlled by a locus or loci located on chromosome 5A of wheat, whereas the cor14b gene was mapped in T. monococcum on the long arm of chromosome 2Am. The analysis of single chromosome recombinant lines derived from crosses between 'Chinese Spring/T. spelta 5A' and 'Chinese Spring/Cheyenne 5A' identified two loci with additive effects that are involved in the genetic control of cor14b mRNA accumulation. The first locus was tightly linked to the marker psr911, whereas the second was located between the marker Xpsr2021 and Frost resistance 1 (Fr1).
T. aestivumAe. biuncialis chromosome addition lines. Ae. biuncialis was crossed as male parent with the winter wheat line Martonvásári 9 kr1 and F1 hybrids were produced, treated with colchicine, and the amphiploid plants were backcrossed with wheat. Ten monosomic chromosome additions (2n = 43) and three double monosomic chromosome additions (2n = 44) were found in the BC3F1 and BC2F2 generations. By selfing these plants, disomic chromosome addition plants could be recovered in the next generation. The differences in the hybridization patterns of the two parents observed after FISH with the repetitive probe pSc119 will enable us to further identify the alien chromosomes added to wheat.
Zs. Pónya, É. Darkó, É. Szakács, I. Tímár, and B. Barnabás.
Our scientific endeavours encompass developmental plant biology focused on the early steps of zygotic development and gamete-gamete interactions. Although in animal biotechnology, gametes have been successfully used for a considerable time as target cells for micromanipulation, in angiosperms these techniques did not emerge until as late as the 1990s. In our laboratory, techniques utilizing the processes of sexual reproduction in higher plants as a promising way of introducing genes of foreign origin into zygotes of cereals produced in vitro by electrofusion open up new vistas in the realm of transgenic research.
Our system enables us to deliver genes, proteins, and other biologically active materials in minute amounts directly into the nuclei of female gametes/zygotes of cereals by exploiting a novel immobilization procedure elaborated at our laboratory. The coupling of this method with sophisticated culture techniques may produce fair prospects in establishing an innovative approach in transforming cereals and in analyzing the molecular and cellular biology of fertilization and in vitro zygotic embryogenesis such as signal transduction triggered by sperm-egg cell binding and fusion with particular regard to calcium signalling and cytoskeleton dynamics. Furthermore, techniques for nuclear transfer of the female gametes and karyoplast-subprotoplast fusions also are being worked out and exploited in parthenogenesis research. Under the auspices of a domestic cooperation cell-cycle, studies based on microinjection and transient expression of GFP also are carried out at the Sexual Plant Reproduction Group of the Department of Cell biology and Plant Physiology of the Agricultural Research Institute of the Hungarian Academy of Sciences.
The other major area of our research activities are to investigate the possibility of selection for aluminium-tolerant DH lines from wheat anther culture. For this purpose, anthers from the cultivar Mv16 are cultured on a solidified W 14 induction medium supplemented with 50 and 100 µmol/l aluminium sulfate, at low pH (pH4.5). After 5 weeks of induction, the obtained embryoids are regenerated on 190-2 regeneration medium supplemented with Al in the concentrations as mentioned above. The offspring generation is tested in hematoxylin staining test to define the Al tolerance of the obtained DH lines. According to the results obtained, Al added to the induction media seems to have no negative effect on the androgenic responses (anther response, induction frequency of embryo-like structures and their regeneration ability) of the genotype examined. According to our observations the application of in vitro Al selection significantly increases the probability of obtaining DH lines with significantly higher tolerance, compared to the original genotype. Seeds of 10 selected DH lines are multiplied under field conditions for physiological studies. Seeds of the R4 generation are germinated in Al-containing media, and the root and shoot growth characteristics are measured after 10 days of germination. The chlorophyll and Al contents also are determined. In physiological tests, root and shoot elongation is measured. The toxic effect of Al also is tested in the chlorophyll content of the leaves.