GrainGenes

Cereal Research Institute

POB 391, 6701, Szeged, Hungary.

New cultivars from west Hungary.

J. Falusi, L. Bona, M. Csosz, B. Beke, and J. Pauk.

One of the four Research Stations of the Cereal Research Institute (CRI) is located in Taplanszentkereszt, next to the Austrian border. Climatic conditions of this geographical region (the foothills of the Alps) are different from those in Szeged. This area represents a typical dry, plain. The various climatic conditions offer a good shuttle-selection possibility for breeders at CRI. Three new winter wheat cultivars with improved adaptability were released in 1995 as a result of the shuttle-selection program between the Taplanszentkereszt and Szeged locations.

GK Csornoc is an early ripening, awned, semidwarf (75-90 cm) variety. It was developed by pedigree selection from a segregating population of GK 6077. The stem and the leaves are very waxy. Its winter hardiness and resistance to lodging and tillering are excellent. GK Csornoc was field resistant to powdery mildew and stem and leaf rusts in 1993 and 1994. The flour quality is very good. Loaves made from Csornoc are desirable, and FONT SIZE=2 FACE="WP Greek Century""-amylase activity is optimum. Thousand kernel mass is 48-52 g.

GK Repce. Pedigree: GK 6744/Mini Mano//GK Tiszataj. It is a middle ripening, high-yielding cultivar. Its ear has intermediate length awns distributed on the upper quarter of ear, not along the whole length. It has excellent winter hardiness, good tillering, and field resistance to powdery mildew and stem and leaf rusts. GK Repce has an excellent adaptability to different soil conditions. The yield of GK Repce was 6.64 t/ha (on the average of 35 experiments in the last 3 years). The baking quality and loaf volume are good, thousand kernel mass is 39-42 g, and TW is 79-81 kg/hl.

GK Marcal. Pedigree: 8001/Karcag dwarf//Sava/BleTom/3/Mini Mano. This variety is a middle ripening, awned, high-yielding cultivar with good grain and flour quality parameters. Lodging and frost resistance are excellent. Thousand kernel mass is 43-47 g; TW is 80 kg/hl. The good adaptability to a range of environments will allow for wide spread of this cultivar.

Comparison of variety maintenance methods in wheat.

Cs. Kertesz, J. Matuz, J. Proksza, and Z. Kertesz.

Three maintenance systems were evaluated in a study on two different cultivars for Pedigree 1, single plant progenies were grown in a spaced planting system (50 x 10 cm spacing), and their progenies were tested in yield trials under normal density. For Pedigree 2, single heads were selected, head rows were evaluated, and the progenies of the head rows were tested in yield trials. In the third system (Jensen's bulk method), a thousand heads were selected and blends of the head rows were harvested as breeders' seed.

It was found that all three methods are suitable to achieve adequate homogeneity during the maintenance process, but Pedigree 1 is the most expensive and space- and time-consuming. In the two pedigree methods, the most improved breeders' seed was achieved when the variety component strains were selected for seedling vigour/yield or farinograph value. The number of strains involved did not have an effect on the yield of the breeders' seed. The yield reactions of the two model varieties were different, so breeders should choose the appropriate method.

The most economic system was the mass selection-based "Jensen method", although the Pedigree 2 system generally seems most promising.

Gene bank.

L. Cseuz.

Gene bank activity has begun in the Wheat Department with the support of the Hungarian Ministry of Agriculture. The main goal of the gene bank program is the preservation of the local old varieties, variety candidates, or lines selected by the Institute carrying important characteristics that could be useful for breeding. We also conserve important genetic resources for disease and pest resistance and for quality from all over the world.

Five hundred genotypes, in 3,000 stored entries, were evaluated according to the suggestions of the International Board of Plant Genetic Resources. The system focuses on morphological and highly heritable agronomic characters. In 500 samples, gliadin curves of 200 lines were evaluated by HPLC. Resistance to leaf rust (Puccinia recondita f.sp. tritici), stem rust, (Puccinia graminis f. sp tritici), and powdery mildew (Erysiphe graminis f. sp. tritici) was scored by the modified Cobb's scale at the adult stage and by Stakman's scale at the seedling stage. The evaluation will be repeated in the next season, and the multiplied seeds will be preserved as a base collection; another 500 entries will be included in the active collection. On the basis of these results, we select genotypes from the active collections and include them in our crossing program. Seed samples of the entries are stored in glass containers in a cold chamber (at 5 C).

Amino acid analysis.

T. Bartok, G. Borcsok, and F. Sagi.

A new, automated, high-speed, RP-HPLC/FL method was developed for analysis of amino acids. This method involves a two-step precolumn derivatization with o-phthaldialdehyde/3-mercaptopropionic acid (OPA/3-MPA) for primary amino acids and with 9-fluorenylmethyl chloroformate (FMOC-Cl) for secondary amino acids. The OPA/3-MPA derivatives eluted within 6.5 min, whereas the retention time of the last eluted amino acid derivative (FMOC-Pro) was 8.0 min. The total analysis time, including precolumn derivatization, separation, column washing, and reequilibration cycles, was only 18 min. Therefore, 75-80 samples per day can be analysed during unattended operation. The efficiency of the method was demonstrated by the separation of amino acids extracted from potato tubers. This method could be applied efficiently for analysis of amino acids in wheat grain samples.

Resistance of Hungarian wheat varieties to powdery mildew and rusts.

M. Csosz.

The weather was favourable for fungal diseases in 1994. At our station, the rainfall varied from 20-65 mm for the months from September, 1993, to July, 1994. Rainfall was 465 mm during the growing season. The winter was mild, so pathogens increased very quickly and early.

Powdery mildew. About 20-30 % of the leaf surface of the most susceptible varieties were covered by powdery mildew by the middle of April. Severity of infection of the registered varieties varied from 9 to 55 %. Cultivars GK Zugoly, GK Gobe, GK Kincso, and GK Csornoc were resistant to powdery mildew.

The most frequently used genes against powdery mildew did not give appropriate protection; however, several of them provided acceptable protection (such as Pm5/Pm6 from Coker 983, Pm6 from Coker 747, and Pm17 from Amigo).

Leaf rust. In this year, the natural leaf rust infection appeared much earlier than in previous years. Because of the early epidemic, the yield loss was significant in many parts of the country. Severity of infection of registered varieties varied from 1-55 %. The cultivars GK Gobe, GK Bokros, GK Kincso, GK Csornoc, and GK Olt were resistant to leaf rust. GK Zugoly is a late-rusting variety; thus, its yield was not reduced significantly.

Stem rust. Artificial infection was used to study stem rust resistance of winter wheat varieties. The most effective genes were derived from Arthur 71 (Sr36) and Sava (Pm2/Pm6, and an unknown stem rust gene(s)). Variety GK Kincso, derived from an `Arthur 71/Sava' cross, was highly resistant to stem rust infection from 1978 to 1994. In addition, GK Kincso was highly resistant against powdery mildew for the 10-year period 1978-1988. Although its resistance has decreased in the past 7 years, GK Kincso is still one of the best powdery mildew resistant varieties in Hungary. In recent years, its progeny (from the cross of GK Kincso/GK Istvan) gave the most resistant variety, GK Zugoly.

The severity of artificial infection of registered varieties varied from 0-95 %. GK Kincso, GK Gobe, GK Zugoly, and GK Csornoc were very resistant against stem rust.

Yellow rust. Rainfall and low temperature were favourable for an increase of yellow rust infection in May 1994. Epidemics occurred in several parts of the country. Infection of the registered varieties ranged from 0-95 %. Cultivars GK Othalom, GK Kata, GK Zombor, GK Csuros, and GK Orseg were resistant.

Insect resistance.

M. Papp.

In Hungary, the cereal leaf beetle (Oulema melanopus L.) and the bird cherry-oat aphid (Rhopalosiphum padi L.) are the most harmful pests of winter wheat. Resistance tests, based on estimation of leaf-feeding damage by cereal leaf beetle and infestation by bird cherry-oat aphid, were carried out on 52 winter wheat genotypes in 1994. The experiments were performed in isolated conditions in three field cages covered by insect nets. The first cage was supplied with about 5,000 adult cereal leaf beetles at the end of April. Bird cherry-oat aphids were introduced into the second cage by the end of March and April. The feeding damage by cereal leaf beetle was determined on the flag leaf as a percentage of the whole surface. Infestation severity by bird cherry-oat aphid was determined by visual detection as a percentage of surface covered by aphids related to the total surface of the plant. The third cage was used as a control (without infestation), because yield response was also interesting to us. The grain yield of 20 randomly selected heads was measured in infested and noninfested (protected) control plots and was expressed as a percentage of the noninfested control. Thousand kernel mass was measured from the samples.

Average leaf-feeding damage caused by cereal leaf beetle in 52 genotypes studied was 72 % on 30 May. The most resistant cultivars (Downy and GK Reka) had 42-54 % feeding damage, and the most susceptible ones (Mv 13, Szoke-Jbj 50) had 82-83 %. The yield response was somewhat more sensitive in reflecting genotype reaction than the thousand-kernel mass. Yield loss caused by cereal leaf beetle was 43 % on average, whereas thousand kernel mass loss was 30 %. Yield of the tolerant cultivars (Downy, Yubileinaja 50, GK Kovasz, and GK Reka) was reduced by only 23-33 %, whereas that of the most sensitive ones (GK Szoke, GK Favorit, and Mv 13) decreased 55-57 %. A medium correlation was found between leaf-feeding damage by cereal leaf beetle and yield reduction (r = 0.5593, P < 0.001).

Average infestation severity by bird cherry-oat aphid in 52 genotypes studied was 26 % on 27 May. The most resistant cultivars (Downy, GK Csuros, Mv 8, and Korona) had only 12-18 % infestation, whereas the most susceptible ones (GK Mini Mano, GK Korany, Mv 13, and GK Istvan) had 36-43 %. Yield reduction caused by bird cherry-oat aphid was 50 % on average, and thousand kernel mass loss was 34 %. Yield reduction of the most

resistant cultivars (GK Kincso, Downy, Yubileinaja 50, GK Kunsag, GK Zombor, and GK Kovasz) was 23-34 %,

whereas that of the most sensitive ones (GK Orzse, GK Mini Mano, Mv 13, and GK Korany) was 65-84 %. Yield loss correlated closely with the infestation severity of bird cherry-oat aphid (r = 0.6000, P < 0.001).

Induction dwarf mutants and selection for antibiotic-resistant mutants.

L. Purnhauser.

Four dwarf mutants were induced from cv. Siete Cerros after irradiation (15 Krad by Co⁶⁰) of seeds through several generations. In the M₅ generation, the dwarf lines were shorter by 20 cm than the control, Siete Cerros. Although lacking other visible phenotypic deficiencies, the yield ability of the dwarf lines was lower by 10-33 % in field experiments than that of the control. Genetic characterisation of the mutants is in progress using test crosses and the PCR technique.

For protoplast fusion and gene transfer, the use of selectable markers is very important. To transfer cytoplasmic traits (e.g., cytoplasmic male sterility) by protoplast fusion, cytoplasmically selectable markers, such as streptomycin resistance, were very useful in dicots. The base of the in vitro selection is the bleaching effect of streptomycin on the regenerating shoots. The resistant mutants can develop green shoots in the presence of streptomycin.

To induce cytoplasmic mutants in wheat, immature seed of the high- regenerating CIMMYT No. 45 spring wheat line were treated with nitroso-methylurea. Callus cultures than were initiated from the immature embryos of the treated seeds on MS medium supplemented with 1 mg/l 2,4-dichlorophenoxiacetic acid (2,4-D). Calli produced were transferred to a maintaining medium (MS+0.5 mg/l 2,4-D) and then to a regenerating medium (2,4-D-free MS) supplemented with the selective agent, streptomycin (100 mg/l). Up to this time, about 24,000 calli was used for selection. Some green shoots were selected, but during further testing, these also bleached out. In vitro selection for cytoplasmic markers is continuing. This work is supported by OTKA grant No. 5221.

Publications.

Bartok T, Szalay G, Lorincz Zs, Borcsok G, and Sagi F. 1994. High speed RP-HPLC/FL analysis of amino acids after automated two-step derivatization with o-phthaldialdehyde/3-mercaptopropionic acid and 9-fluorenylmethyl chloroformate. J Liquid Chromat 17:4391-4403.

Csosz M. 1994. Possible genetic background of stem rust resistance in winter wheats from Szeged. Cereals-pathogens and stress factors interaction, First International Seminar, September 13-15, 1994. Poznan p. 76 (Abstract).

Csosz M, Cseuz L, Kertesz Z, and Pauk J. 1994. The effects of biotic environmental factors on the yield of different winter wheat (T. aestivum L.) genotypes. In: Plant Production on the Threshold of a New Century (Struik PC, Vredenberg WJ, Renkema JA, and Parlevliet JE eds). Pp. 481-483.

Mesterhazy J, and Csosz M. 1994. Breeding wheat for resistance against powdery mildew in Szeged. 3rd Cereal Mildew Workshop, Cost 817, Zurich/Kappel am Albis, Nov. 5-10, 1994. p. 24 (Abstract).

Papp M and Mesterhazy A. 1994. Resistance of wheat to viruses in field tests. Ann Wheat Newslet 40:128-129.

Papp M. 1994. Resistance of winter wheat to cereal leaf beetle. Ann Wheat Newslet 40:128.

Papp M. 1994. Resistance of winter wheat to cereal leaf beetle and bird cherry-oat aphid. Ann Plant Resistance Insect Newslet 20:36-37.