AGRICULTURAL RESEARCH INSTITUTE OF THE HUNGARIAN ACADEMY OF SCIENCES
Martonvásár, H-2462, Brunsvik str. 2, Hungary.
Wheat breeding.
Z. Bedö, L. Szunics, L. Láng, Lu. Szunics, O. Veisz,
I. Karsai, Gy. Vida, P. Szücs, A. Juhasz, M. Gal,
T. Szederkenyi, and Sz. Bencze.
Wheat season. An unusually mild winter was followed by a dry and windy spring. The wheat recovered after good rains from late April and produced a medium stand of lower than average density. A rainy summer delayed harvest but caused fewer quality problems than in previous years. The moderate epidemics of powdery mildew and leaf rust did not reduce the yield significantly; however, sporadic FHB infection, Septoria, and Helminthosporium was observed. The national yield level of 4.2 t/ha was lower than the potential of the country. The extremely wet autumn delayed planting and reduced the wheat acreage by 20-25 %.
Breeding. Three early maturing Martonvásár-bred winter wheat varieties were registered in 1998.
Mv Tamara was selected from the 'Fatima 2/Martonvásári 8' population. Mv Tamara has good winter hardiness and lodging resistance. The cultivar is resistant to stem rust and moderately susceptible to leaf rust and powdery mildew. The hard kernels have a B1-A2 Farinograph value and a 30-32 % wet-gluten content.
The variety Mv Kucsma (Mv 32-86/Fatima 2) is a good quality bread wheat with similar disease resistance parameters. The stand is 85-90 cm tall with reliable lodging resistance. The heads are awned like those of the other two new varieties. Typical wet-gluten content is over 30 %. The grains are hard and of A2-B1 Farinograph quality.
Mv Martina has outstanding yield potential, nearly 5 % higher than that of Mv Tamata or Mv Kucsma. The pedigree of Mv Martina is 'Fatima 2 / Martonvásári 17'. The cultivar is resistant to stem rust and lef rust and moderately resistant to powdery mildew. Frost resistance is medium. Very good agronomical adaptability and a soft kernel were inherited from the Martonvásári 17 parent. Bread-making quality is medium, but the typical B1 quality can be shifted to A2 or B2 according to the growing conditions.
In parallel with the new registrations, Martonvásári
15, Martonvásári 20, Martonvásári
22, and Martonvásári 24 have been withdrawn from
the National List. At present, 24 Martonvásár winter
bread wheat varieties are marketed within the country and have
a market share of over 50 %.
Quality markers. Biochemical and molecular markers have been used in the selection for bread-making quality. Populations of old Hungarian varieties were used to study genetic variability. Of these, Bánkúti 1201 (released in 1931) and its derivatives consist of heterogeneous populations, and represent special types, because their breadmaking quality is good, although they possess 2+12 or 3+12 HMW-glutenin subunit encoding genes on chromosome 1D.
Our major aims are to compare the subunits 2 or 3 identified in these varieties to the subunits 2 and 3 existing in the well-characterized varieties and to study the role of other wheat storage proteins especially that of LMW-glutenin in the formation of gluten properties. A population of Bánkúti 1201 was analyzed for variation in the band patterns of LMW-glutenin subunits using a modified two-step, 1-D SDS-PAGE. Gliadin components at the Gli-1 loci were identified using A-PAGE. Several bands characteristic of Bánkúti 1201 and its relatives were found at the Glu-3 locus, and they have a favorable effect on technological quality. The linkage existing between the Gli-1 and Glu-3 loci also was established. Based on the literature, the alleles identified in Bánkúti 1201 are rare or do not occur at all in modern varieties.
Old Hungarian varieties were tested with primer pairs that are specific for the upstream, downstream, and repetitive regions of the 1Dx5 and 1Dx2. Based on these results, the majority of the Bánkúti 1201 lines possessed special fragment types differing from the control varieties of the 1Dx2 (Chinese Spring) and 1Dx5 (Cheyenne) genes. The fragments digested with restriction enzymes also resulted in band patterns specific to the Bánkúti 1201.
Based on our results, molecular markers may provide a more detailed analysis in dissecting the exact allele composition of HMW-glutenin subunits and in marker-assisted selection, compared to biochemical markers.
Kernel hardness. Varieties and breeding lines of common and durum wheats included in the Martonvásár breeding program were examined using the Single Kernel Characterization System 4100 to determine the correlation between the kernel-hardness index and other technological quality traits. The majority of common wheat varieties and lines are of the hard-grained type, and only a few have soft grains. The kernel-hardness index of the durum wheat genotypes examined showed a normal distribution. In the case of the T. aestivum samples, the kernel-hardness index was closely correlated with grinding time and moderately correlated with flour yield, farinograph index, and farinograph water absorption. The kernel-hardness index of the durum wheat samples tested showed the closest correlation with vitreousness and grinding time. The results of principal component analysis indicated that kernel hardness index could be grouped primarily with the milling properties of grinding time, flour yield, and vitreousness. Varieties of the hard-grain type are Mv Magvas, Mv Vilma, Mv Palma, Mv 16, Mv 19, Mv Optima, Fatima 2, Mv 21, Mv Szigma, Mv Magdalena, Mv Madrigal, Mv Tamara, Mv Kucsma, Mv Mezöföld, Mv Matador, and Mv Emma. The soft-grain type is characteristic of Mv Irma, Mv 17, Mv Koma, Mv Summa, Mv 23, Mv 25, and Mv Magma.
Disease studies. In 1998, Fusarium infection was recorded throughout Hungary and caused marketing problems for wheat-growing farms, despite the fact that the infection was not as severe as in 1997.
The weather was not favorable for the development of a leaf rust epidemic, and even in an artificially inoculated nursery, the primary infection was delayed. Leaf rust resistance genes Lr9, Lr19, Lr23, Lr24, Lr25, Lr27, Lr28, Lr34, Lr37, Lr38, and LrW gave satisfactory resistance to the Hungarian rust population in 1998. We have joined the Winter Wheat Nursery for Adult Plant Resistance to Leaf Rust, organized as part of the COST 817 Action. The first results for our varieties should be available in 1999.
In some parts of the country, a mild powdery mildew epidemic was recorded. In virulence surveys, 210 isolates were examined on seedlings in the greenhouse, and 27 races were identified using the differential set recommended by Nover. The dominant races and their frequencies are 51 (23.81 %), 90 (15.24 %), 70 (11.43 %), 72 (9.05 %), and 59 (7.14 %). With the exception of resistance gene Pm4a (Khapli), the known major resistance genes did not provide full protection against the pathogen. Below-average virulence was recorded for differentials bearing the resistance genes Pm1+2+9 (20.47 %), Pm4b (25.71 %), and Pm2+Mld (39.04 %).
Stem rust has not caused an epidemic in Hungary for several decades because of the excellent resistance of the cultivated varieties. Because we cannot ignore the possible breakdown of resistance, new sources are constantly being tested and identified in artificial inoculation nurseries. Stem rust resistance genes Sr31 and Sr36, which are found in the majority of Hungarian winter wheat varieties, provide excellent resistance against the present race population, although Sr7a, Sr9b, Sr11, Sr24, Sr27, and SrGT also provide a satisfactory level of resistance.
The majority of recently developed Martonvásár wheat varieties have good powdery mildew resistance (Mv Summa, Mv Magdaléna, Mv Mezföld, and Mv Martina) and leaf rust resistance (Mv Magdaléna, Mv Magvas, Mv Tamara, Mv Martina, and Mv Kucsma), and practically all of them have excellent stem rust resistance. All the cultivated varieties are moderately susceptible to FHB and bunt. Thus, the complex resistance or slight susceptibility of the varieties provides adequate protection against a number of pathogens simultaneously. When these varieties are grown, the production costs are increased only slightly, if at all, by the need for chemical plant protection, and the biological environment also suffers less pollution.
Abiotic stress-resistance studies. Phytotron facilities provide an excellent opportunity for research on abiotic stress resistance. The dynamics of frost resistance in winter cereals were studied in a phytotron. The hardening process of durum wheat genotypes also was traced. Winter durum wheat varieties acquire a maximum state of hardiness after 3050 days of hardening. Frost resistance in plants kept at 2°C for 60 days or more drops considerably. At their maximum hardiness, the most frost-resistant T. durum varieties have frost resistance equal to or exceeding that of moderately frost-resistant T. aestivum varieties. The hardening of durum wheat varieties takes place within a shorter period than that of T. aestivum varieties and also is lost more rapidly and to a greater extent at lower temperatures.
One reason for the poorer frost resistance of T. durum wheat varieties is the dynamics of hardening, which differs from that of T. aestivum. Consequently, repeated freezing (late winter frosts without snow cover) leads to a high rate of frost-kill. Another reason is that tetraploid durum wheats lack the D genome. In experiments on substitution lines, the chromosomes 5D and 6D were found to have frost-resistance genes that significantly improved the frost resistance in hexaploid wheats with poor frost resistance.
The frost resistance of lines 5A, 7A, 4B, 5B, 1D, and 5D of a Chinese SpringCheyenne substitution series raised and hardened under long-day (16 h) illumination was significantly better than that of plants grown under short day illumination. The effect of daylength in increasing frost resistance could be demonstrated for chromosomes 5A and 5D when frozen at either 10°C or 12°C. An increase in the length of illumination during early growth and hardening promotes the development of better levels of frost resistance. The greatest positive effect was manifested for the above-mentioned chromosomes, which had significantly better frost resistance than the disomics even under normal daylength.
In cooperation with U.S. researchers, we were the first to use magnetic nuclear resonance spectroscopy to determine the quantity of water present in the tillering node of wheat and to study changes in its physical state. An examination of control and hardened plants indicates that in the course of hardening, the water content of the tillering node in winter wheat decreases in absolute terms, while the quantity of water-soluble carbohydrates increases.
The images obtained with magnetic nuclear resonance spectroscopy
can be used to determine the magnitude and location of frozen
tissues within the tillering nodes of hardened and control plants.
On the basis of changes in these images, we could pinpoint the
site of frost damage and the course of the process over time.
Necrosis first appeared in the outer parts of the tillering node,
spread towards the middle of the tissues, and affected larger
areas as the temperature declined.
J. Sutka, G. Galiba, M. Molnár-Láng, G. Kocsy, B. Köszegi, G. Linc, A. Vágujfalvi, and E. D. Nagy.
Cytogenetics of Ae. cylindrica. The genomic constitution of Ae. cylindrica was analyzed by C-banding, GISH, and FISH using the DNA clones pSc119, pAs1, pTa71, and pTA 794. The C-banding patterns of the Dc- and Cc-genome chromosomes of Ae. cylindrica are similar to those of D- and C-genome chromosomes of the diploid progenitor species Ae. tauschii and Ae. caudata, respectively. These similarities permitted the genome allocation and identification of the homoeologous relationships of the Ae. cylindrica chromosomes. FISH analysis detected one major 18S-5·8S-25S rDNA locus in the short arm of chromosome 1Cc. Minor 18S-5·8S-25S rDNA loci were mapped in the short arms of 5Dc and 5Cc. 5S rDNA loci were identified in the short arm of chromosomes 1Cc, 5Dc, 5Cc, and 1Dc. GISH analysis detected intergenomic translocation in three of the five Ae. cylindrica accesions. The breakpoints in all translocations were noncentromeric with similar-sized segment exchanges. This work has been done with the coöperation of Dr. B. Friebe (Kansas State University, Manhattan, USA).
Wheatbarley translocations. Wheatbarley translocations
were identified by GISH in backcross progenies originating from
in vitro-regenerated 'wheat (Chinese Spring) / barley (Betzes)'
hybrids. The regenerated hybrids were pollinated with the wheat
line Martonvásári 9 (kr1), and the BC2F1
and the BC2F2 seeds were analyZed by GISH. Fifty-one BC2F1 seeds
from 17 BC2 plants were examined. Wheatbarley translocations
were found in 12 of the BC2F1 seeds, originating from five of
the 17 BC2 plants. Five different translocations were identified.
GISH analysis mapped the translocation breakpoints at fraction
lengths of 0.5 and 0.8 with the distal segment being derived from
barley in three terminal translocations. In one terminal translocation
with the translocation breakpoint at a fraction length of 0.5,
the barley chromosome segment was derived from a SAT chromosome,
either 5H or 6H. In one submetacentric chromosome, the translocation
breakpoint was in the short arm at a fraction length of about
0.2, the distal segment being derived from wheat and the rest
of the chromosome from barley. The other arm of this chromosome
was derived from a barley SAT chromosome. Sequential N-banding
and GISH analyses further identified the translocation chromosomes.
Three of the translocation chromosomes lacked diagnostic N-bands
and could not be identified. The N-banding pattern of the Robertsonian
translocation suggests that this chromosome consists of the short
arm of barley chromosome 4H translocated to the long arm of 2B
of wheat. Plants with four different homozygous wheat-barley translocations
were selected from the self seed of the BC2F2 generation.
Wheatrye hybrids. The hexaploid winter wheat Martonvásári
9 kr1 (Mv9kr1) possessing recessive crossability alleles (kr1kr1kr2kr2)
was pollinated with the rye cultivar Lovászpatonai. The
mean crossability percentage was fairly high (68.4 %). The chromosome
number distribution was examined in mitotic chromosome spreads
of octoploid triticale obtained via colchicine treatment of the
initial hybrid, and it was found to range from 51 to 56. Eighteen
amphiploid (C1) plants were backrcrossed with Mv9kr1 for
the purpose of producing addition lines and subsequent alien gene
transfer into wheat. All the rye chromosomes were identified in
mitotic chromosome spreads of octoploid triticale with the help
of C-banding and FISH.
Alterations in carbohydrate content. Water-soluble carbohydrates
contributing to genotypic differences in response to consecutive
drought and salinity stresses in wheat seedlings were investigated.
Total water-soluble carbohydrate; glucose, fructose, sucrose,
and fructan contents; and the distribution of the degree of polymerization
in the fructans were measured in wheat seedlings exposed to 18
% PEG-induced drought stress followed by an equiosmolar salinity.
Tolerant genotypes accumulated higher soluble carbohydrate levels
than the sensitive ones. Both ionic and nonionic stresses increased
the distribution of reducing sugars. The concentration of the
principal component of soluble carbohydrate content increased
in response to drought stress and, conversely, decreased from
salt stress. PEG-induced fructan accumulation was highest in leaves
and showed a positive correlation with the drought tolerance of
the varieties. The fructan content in stems increased in tolerant
genotypes but decreased in sensitive ones under salt treatment.
Polyfructan distribution was greater in tolerant varieties than
in sensitive ones.
A physical map for the Vrn-A1 and Fr1 loci. Homozygous
deletion lines of chromosome 5AL generated in Chinese Spring were
tested for flowering time without vernalization and for frost
resistance after cold hardening. The Vrn-A1 gene for vernalization
requirement mapped between breakpoints 0.68 and 0.78, whereas
the frost resistance gene Fr1 was flanked by deletion breakpoints
0.67 and 0.68. This confirms previous evidence that these genes
are linked, and the two characteristics are not the pleiotropic
effects of a single gene. A comparison between the physical and
genetic maps for Vrn-A1 and Fr1 loci, together with
genetic maps, could be useful in the further study of genome synteny
and in elaborating a gene-cloning strategy.
B. Barnabás, E. Páldi, G. Kovács, T. Janda, I. Takács, G. Szalai, Z. Pónya, I. Timár, P. Finy, and M. Solymoss.
Morphological characterization of wheat egg-cell protoplasts isolated from immature and overaged caryopses. The morphological features and fine structure of wheat egg-cell protoplasts isolated from premature and overaged caryopses were compared. Except for shape, the young egg-cell protoplast showed the same morphological characteristics as that of egg cells in plants at the time of anthesis. Young and adult egg-cell protoplasts were spherical in shape. Polarity could not be identified exactly with the method used. During aging, the egg cell increases considerably in volume. The adult egg showed the typical features of programmed cell death. After a long life-span (about 18 days), cells of the female gametophyte appear to undergo apoptosis.
Optimization of transforming egg cells/zygotes of wheat via microinjection. An expeditious and highly efficient technique of microinjecting egg cells/zygotes of wheat was developed to address questions related to unravelling the first steps of zygotic embryogenesis in wheat. Using a mechanical dissection method and a novel immobilization approach enabled us to microinject approximately 15 egg cells of wheat per hour. After exposure of the protoplasts to a high-frequency AC field for immobilization, a significantly higher transformation rate (46 % and 52 % for egg cells and zygotes, respectively) could be achieved than has been reported for plant protoplasts (Schnorf et al. (1991). Whether this high transformation efficiency was due to the high frequency electrical field applied is unknown. The transformation rate appeared to be dependant upon the time of egg-cell isolation. According to ultrastructural observations, this may reflect a variation in competence of the egg cells during in situ development. In studies directed towards establishing the optimal time-window for DNA delivery into the fertilized egg cell, we quantified the time course of DNA dynamics during the zygotic cycle via quantitative microspectrofluorometry.
Regeneration of fertile, doubled haploid plants from a colchicine-supplemented
medium in wheat anther culture. Genome doubling is critical
for obtaining fertile, doubled haploid plants from wheat anther
culture. The most common doubling method applies colchicine to
the plant. However, the conventional treatment has several disadvantages.
Anther cultures of one winter and two spring wheat genotypes were
treated with 0.03 % of colchicine for 3 days at the beginning
of microspore induction. Colchicine added to the induction medium
had no negative influence on the androgenic responses of the genotypes
examined. The spontaneous doubling rate of the varieties studied
in this experiment was quite low, underlying the need for an efficient
genome doubling system. Significantly higher fertility was observed
in the plants originating from the colchicine-supplemented induction
medium in all genotypes, but significant differences occurred
in the level of fertility. In winter wheat, the colchicine treatment
resulted in 100 % completely fertile plants with a high seed-setting
ability. In the spring varieties, even after the colchicine treatment,
several plants showed incomplete fertility, suggesting that further
improvement of the method is needed. We found that application
of colchicine prior to the first microspore mitosis was superior
to the conventionally used chromosome doubling methods and could
be introduced to wheat breeding program.
Publications.
Bedö Z, Vida Gy, Láng L, and Karsai I. 1998. Breeding for breadmaking quality using old Hungarian wheat varieties. Euphytica 100:179-182.
Karsai I and Bedö Z. 1998. Relationship between the anther culture response and aluminium tolerance in wheat (Triticum aestivum L.) Euphytica 100:249-252.
Kerepesi I, Galiba G, and Bányai E. 1998. Osmotic and salt stresses induced differential alternation in water-soluble carbohydrate content in wheat seedling. J Agric Food Chem 46:5355-5361.
Köszegi B, Friebe B, and Sutka J. 1998. Cytogenetic studies on Triticum aestivum-Aegilops cylindrica hybrids and derivatives. Acta Agric Hung 46:1-7.
Molnár-Láng M, Linc G, and Sutka J. 1998. Detection of barley chromosomes in wheat-barley hybrids and their derivatives by genomic in situ hybridization. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 3:28-30.
Nagy D E, Linc G, and Lángné-Molnár M. 1998. Molecular cytogenetic analysis of a new wheat-rye hybrid with C-banding and genomic in situ hybridization (GISH). Növénytermelés 47:253-260.
Pónya Z, Tímár I, Szabó L, Kristóf Z, and Barnabás B. 1999. Morphological characterization of wheat (T. aestivum L.) egg cell protoplasts isolated from immature and overaged caryopses. Sex Plant Reprod 11:357-359.
Sarma RN, Gill BS, Sasaki T, Galiba G, Sutka J, Laurie DA, and Snape JW. 1998. Comparative mapping of the wheat chromosome 5A Vrn1-A1 region with rice and its relationship to QTL for flowering. Theor Appl Genet 97:103-109.
Snape JW, Semikhodskii A, Sarma R, Korzun V, Fish L, Quarrie SA, Gill BS, Galiba G, and Sutka J. 1998. Mapping vernalization loci in wheat and comparative mapping with other cereals. In: Proc 9th Inter Wheat Genet Symp (Slinkard AE ed). University Extension Press, Saskatoon, Saskatchewan, Canada. 3:156-158.
Szunics L, Bedö Z, Szunics Lu, Láng L, and Veisz O. 1998. Results of durum wheat breeding in Martonvásár. Acta Agr Hung 46:135-148.
Tischner T, Köszegi B, Veisz O, and Sutka J. 1998. Environmental control