GrainGenes

ITEMS FROM CROATIA

 

Bc INSTITUTE FOR BREEDING AND PRODUCTION OF FIELD CROPS

Department of Cereal Crops, Marulicev trg 5/I, 10000 Zagreb, Croatia.

 

Slobodan Tomasovic, Petar Javor, Rade Mlinar, and Branko Sesar.

Achievements in wheat breeding and seed production of the Bc Institute for Breeding and Production of Field Crops-Zagreb in Croatia.

Yield and stability of yield through breeding wheat for resistance against the main wheat diseases and quality of the recently winter wheat varieties developed by the Bc Institute.

Summary. Winter wheat breeding at the Bc Instftute-Zagreb is conducted within several programs, the main objective of which is development of modern semidwarf and moderately high winter wheat cutlivars with increased productivity, wide adaptability, and improved grain, flour and bread quality.

Since 1964 (when the cultivar Vuka was registered) until today, 70 winter wheat cultivars developed by the Bc Institute-Zagreb have been registered. Genetically, these cultivars present a supreme achievement in breeding, and are widely accepted by producers both at home and abroad. The most recent Bc winter wheats were registered in 1994 and 1995 and are Patria, Plodna, Ida, Miadenka, Vitina (registered by the Committee for Variety Registration of the Republic of Croatia in 1994), Miholca (registered by the Committee for Variety Registration of the Republic of Slovenia in 1995), and Pakra (registered by the Committee for Variety Registration of the Republic of Croatia in 1995). Of all the above, Pakra produced the highest grain yield (the mean for 1992-94 was 7,670 kg/ha), compared to Sana (7,090 kg/ha) and Zitarka (6,280 kg/ha), which is 8.18 % (580 kg) higher than Sana and 22.03 % (1,385 kg) higher than Zitarka. Patria produced an average of 6,843 kg/ha in 1992-93, compared to Sana (6,569 kg/ha) and Zitarka (5,854 kg/ha), which is 4.17 % (274 kg) more than Sana and 16.89 % (989 kg) more than Zitarka. These yields were very stable throughout wide wheat-growing regions. Ida, Mihelca, Plodna, Mladenka, and Vitina also produced high grain yields.

With respect of the quality of grain, flour, and bread, the newly registered Bc winter wheatz achieve remarkable results. The protein content of Pakra was 14.31 % and a sedimentation value of 36 ml, put it in quality class II and often class I; and to a high group B1 (63.2) and sometimes A1 (77.0 A1). Protein content in Patria was 13.87 % and the sedimentation value was 53 ml. Patria belongs to quality class I or II, and the high B1 group (65.7) or often A2 (74.6). Vitina also has a high protein content (14.61 %) and sedimentation value (44 ml). Vitina belongs to quality class I, and has a high flour quality belonging to group A2 (71.1). These cultivars are typical bread wheats. The high-yielding cultivar Ida is a typical specific-purpose wheat intended for use by the confectionery industry (cakes, cookies, and sponge-cakes). Ida has a lower protein content (12.52 %) and sedimentation value (17 ml), and belongs to a high group C1 (34.5).

In the most recent breeding winter wheat cycles in the Bc Institute-Zagreb, a large number of Bc varieties (lines) with high yielding capacity and pronounced yield stability in production have been developed. A marked improvement of grain, flour and bread quality also has been achieved in comparison with earlier-bred cultivars. This area is receiving special attention to meet severe demands of the market. The result of our many-year work on breeding wheat with the above traits are exactly developed and registered especially the recently Bc winter wheat cultivars.

Work on the breeding of durum wheats at the Bc Institute-Zagreb in Department of Cereal Crops in Botinec began prior to 1985. Because a large part of the Republic of Croatia (Istra and Dalmatia provinces) has a Mediterranean climate, we were encouraged to begin breeding durum wheats for the needs of the Republic of Croatia. More than 2,500 lines and cultivars were collected. Much of this germplasm has good properties for use in breeding (winter hardiness, good spike fertility, low stature, culm strength, size and position of leaves, good resistance to fungal diseases, and plant height). Two Bc lines of durum winter wheat with good agronomic traits were submitted for registration to the National Committee of the Republic of Croatia; Bc TD 3201/92 and Bc TD 3200/92 (Tomasovic et al. 1995). The line Bc TD 3201/92 was released under name Primadur om 1997.

Introduction. Wheat breeding in Croatia began soon after the first attempts in the world in incorporating traits of parents into their progeny by crossing. In 1911, a paper by Dr. Gustav Bohutinsky was published in 'Gospodarska smotra' entitled 'Crossing squarehead x Banatska brkulja'. The highest yielding cultivar grown between two world wars was the Croatian cultivar U1 (Osjecka sisulja) developed by Dr. Mirko Koric. As a leading cultivar, it was widely grown until the newer Italian cultivars were introduced. Breeding of winter wheat at the Bc Institute-Zagreb began in 1947 by Dr. Josip Potocanac. After much research on Italian wheats, which had been grown in Croatia after 1956, and because of the lack insufficient winter hardiness, he established new wheat cultivars by combining the good traits of Italian and American wheats. From this concept two famous cultivars were released, Ziatna dolina and Sanja. Zlatna dolina received international attention and was 15 % higher yielding under wide production than the leading Italian cultivar Libellula (Martinic-Jercic 1990). Stabilizing high yield was the target of the next phase in breeding wheat over resistance to the most important fungal diseases powdery mildew, stem rust, Septoria spp., and Fusarium spp. This model of wheat cultivar production is still followed, with some changes and improvements. Drs. Javor, Tomasovic, and Mlinar still continue this breeding work. This breeding stratedgy produced 70 cultivars (one winter durum wheat), and of these, 16 were grown in foreign countries (Hungary, Italy, Czechoslovakia, Bulgaria, and Slovenia).

Breeding program. Breeding new winter wheat cultivars and genetic investigations at the Bc Institute-Zagreb is accomplished within several programs. The basic objective is to develop semidwarf and moderately tall varieties with increased productivity, wide adaptability through resistance to the main fungal diseases, earliness, and improved kernel and flour quality. The Bc lnstitute-Zagreb possesses a large gene pool of different genetic materials with various wheat agronomic traits. To broaden the genetic variability of crosses, breeding uses a modified pedigree method with discontinual individual selection. Presently, the breeding program aims to further boost yield capacity by increasing the number of spikeletes per spike, but at the same crop density as in the well-known Bc cultivers Baranjka and Super Zlatna.

A remarkable contribution to the higher number of kernels per spike was with the discovery of genes that control branching (Ramifera), four-rowing (Tetrastichon), and normal spike form in T. aestivum (Rm, Ts, and Nr genes). These genes, discovered and determined by Dr.Svetka Koricc (Koric 1972), enable us to prolong spikes and increase the number of kernels. Branching genes are frequently used for developing highly productive, normal spikes. The highest production per spike obtained was 103 kernels. A high number of kernels in a normal wheat spike is influenced by the pleiotropic effect of these genes in relation to higher 1000-kernel weight and increased number of kernels per spike.

The new lines have nryerrm 20 and 27 fertile spikelets. Among the genotypes developed for higher production per spike are some with 33 spikelets per spike. Data on wheat with this number of spikelets is not found in the literature. The cultivar Zlatna dolina has about 16 spikelets and a 1,000-kernel weight near 35 g.

Further improvements in 1,000-kernel weight, and kernel and flour quality are presently evaluated in three programs with the common goal of achieving yields of 15 T/ha. In 1983 and following years, the top yields of some our cultivar in good years were over 10 T/ha in field production.

The winter wheat seed production program at the Bc Institute-Zagreb. According to Croatia's program for advances in wheat production, one of the basic tasks of the Bc Institute is to provide a sufficient quantity of high quality seed (superelite and elite) to satisfy the Croatia's seed requirements and also for export. The production of wheat seed is coördinated between the Institute and the producers (state farms), which are adequately equipped for the modern production of wheat seed.

Bc winter wheats represent the leading seed material in Croatia, because of their positive traits, adaptability to local growing conditions, and production technology. The production of basic seed is by maintaining the elite through multiple selection of the best progenies (single rows) of selected spikes within a cultivar's population. Chosen selected spikes are analyzed in the laboratory, and after visual selection are propagated in single rows. Off types from single rows that differ from the basic type of the cultivar are discarded before the selected progenies of spikes are harvested in bulk. In this way, seed of a super elite category is obtained. Subsequent categories of seed are propagated from the super elite.

Results of wheat breeding in the Bc Institute-Zagreb. Bc wheats have a high yielding potential and are suited for the different agro-ecological growing conditions, a significance in their use both in Croatia and the neighboring countries. Following Zlatna dolina and Sanja, cultivars from the Bc Institute-Zagreb were grown in over 70 % of the wheat acreage in Croatia in 1984 and 50 % today. Zlatna dolina, Sanja, Super Zlatna, Baranjka, Lonja, Zagrepcanka, Adriana, Korona, Marija, Mihelca, Plodna, Anita, Olga, Tina, Davorka, and Mladenka also were grown in other countries.

Between 1983 and 1986, Bc wheats dominated the harvested acreage in the Republic of Croatia. Up to 1985, Bc cultivars increased steadily in seed production where they accounted for 96 % of the harvested area in Croatia. After that period, production fell to 50 % and a new growing trend was noticed. (Table 1). The highest amount of seed was produced in 1987. Despite war conditions (1991-94), permanent growth of marekted seeds of Bc wheat cultivars can be noticed for that period, signifying a significant contribution of the Bc Institute-Zagreb to the nation's seed production.

 

 

Korona (Sana) and Marija are specially distinguished among the new Bc winter wheat cultivars. Because of their high yield capacity and results from agricultural production both at home and abroad, these wheats serve as the standards for the Committee for Registration of new wheat varieties (Korona, the standard of the Committee of the Republic of Croatia and Marija, the standard of the Committee of the Republic of Slovenia). Both Korona and Marija satisfy the strict criteria of the market, because of their high yield and improved kernel and flour quality. Following Marija and Korona, are Alona, Adriana, and the new cultivar Ida, which represents excellent material for the confectionary industry.

Bc wheats and advanced lines from the latest cycle of breeding that are entering production are Darka, Rina, Melita, Davorka, Sandra, Sutla, Olga, Rugvica, Tina, Mladenka, Patria, Pakra, Plodna, Vitina, Mihelca, ZG 4160/91, ZG 4166/91, ZG 31/91, and ZG 18/91, among others. In normal years and when planted at the optimal time (10-25 October) they produce yield well above 8 T/ha of dry grain, and about 10 T/ha in micro-trials. Line ZG 4160/91 produced 10,720 kg/ha, which is 7.15 % (716 kg) above the standard Korona.

A certain amount of progress has been made in the latest Bc cultivars and lines in terms of kernel and flour quality. Higher protein content levels and sedimentation values also were achieved, with many cultivars or lines often belonging to quality class I and II. New cultivars and lines exhibit good farinological properties, of which water absorption is emphasized. Extensograph values also are relatively good. Increases in the 1,000-kernel weight are highly pronounced, i.e. 40-45 g or more, and indicate increased seed quality. In some material, the increase is 50 g or more compared to the cultivars from earlier breeding programs. The old variety Zlotna dolina averaged a 1,000-kernel weight between 30-35 g. The new cultivars are distinguished by high levels of resistance to the most important fungal diseases affecting wheat. These modern cultivars have moderately tall stems of good strength and are very resistant to lodging, and are of mid-early maturity.

Work on breeding hard winter wheat (Triticum durum Desf.) in Croatia. The collecting of durum wheats at the Institute for Breeding and Production of Field Crops in Department of Cereal Crops in Botinec began prior to 1985, when it was realized that the country needed its own durum wheat cultivars. Until recently, work on these wheats had not received much attention compared to aestivum wheats, because of their narrower area of distribution. However, aestivum wheats are more winterhardy and adapted to the western part of the country where winters are severe. Soft wheats are primarily lower in kernal and flour quality, and unsuitable for the pasta industry as compared with durum wheats. The coastal regions (Istria and Dalmatia) have a climate similar to Italy, Greece, and other Mediterranean countries. Thus, we initiated a breeding project on durum wheats. A collection of durum winter-type wheats followed. First, materials from Hungary and then France were evaluated for their agronomic characteristics at our experimental field in Botinec. The lines also were screened for resistance to the main wheat fungal pathogens under of natural and artificial infection.

Contacts with the international centers that conduct research on durum wheat were made. By 1988, we had received materials from ICARDA (Aleppo, Syria), in 1989 from CIMMYT (Mexico), and in 1990 from the CIMMYT-ICARDA project in Turkey (Ankara and Emek). Coöperation with Romania and Russsia followed, and their materials were carefully monitored and selected, because of their high winter hardiness and good spike fertility. We looked for good spike fertility, high kernel and flour quality, and for disease resistance. Some material was obtained from Italy, Chile, and Argentina. In 1992, we received an important collection of durum wheats from the U.S. (Idaho, 1,127 entries), which includes durum lines from nearly all the durum wheat-growing countries in the world. We now are in possession of a very rich and unique collection of durum wheats, with wide genetic and geographical diversity.

Each year a considerable part of the genotype were selected for intercrossing. Progeny from crosses of lines from Turkey, Russia, and Romania were monitoredfor winter hardiness and spike fertility. The selected progenies were planted in preliminary varietal trials (7.5 m2 plots) in 1991­92, and their progenies were increased in 1993 on 30 and 60 m2 plots (limited increase from the sixth repetition). In 1994, the selected durum wheats were planted in small-scale trials using a German wheat as check). These investigations are continuing from 1995 to the present.

The following Bc lines of durum winter wheat have been chosen for their good economic traits: Bc TD 3199/92, Bc TD 3200/92, Bc TD 3201/92, Bc TD 3205/92, and Bc TD 3208/92.

The following lines of durum wheat have been submitted for registration to the National Committee of the Republic of Croatia: Bc TD 3200/92 and Bc TD 3201/92.

Conclusions. In summary, the achievements in breeding of Bc winter wheats are the result of continuous breeding work include:

Wheat cultivars and lines with yield capacities well above 10 T/ha were developed, achieved by improving the genetic basis and wide adaptability to different agro-ecological growing conditions.

The high yield stability of the new Bc cultivars and lines is maintained through genetic resistance to the most economically important fungal pathogens. Compared to some older wheats, significant progress was made in wheat breeding in terms of improved kernel and flour quality. Lines with markedly improved yield and kernel and flour quality have been developed. Higher total protein percentage and increased sedimentation values were achieved.

The new cultivars and the latest lines are distinguished by very good farinological characteristics, especially for water absorption, which produces better bread keeping quality and the economy in the baking industry. Extensograph values for the new wheats also are improved when compared to older wheats.

The latest cultivars and lines show marked progress for kernel quality, especially in higher 1,000-kernel weight relative to older varieties.

Spike length was increased, reflected in a higher number of spikelets per spike (33), increased number of kernels per spikelet (3-5), and total number of kernel per spike (103).

Stem strength was increased resulting with good lodging resistance.

The Bc Institute-Zagreb has made a large contribution to the production of winter wheat seed in Croatia, ranking among the best in the world.

There was steady increase in seed production of Bc wheat cultivars up to 1985, when they accounted for 96 % of the harvested area in the country. Production has decreased to 50 % since that time, but new trends in growth have been noticed.

Excluding common wheat, we started breeding work on durum wheat in 1985. We payed special attention to agro-ecological traits such as winter hardiness, spike fertility, semidwarf stature, culm strength, leaf size and position, and length of vegetation period. For choosing parents, genotypes with high levels of resistance to fungal pathogens, especially to Fusarium and Septoria spp, were used. The best durum lines (Bc TD 3201/92 and Be TD 3200/92) were submitted for registration to the National Committee of the Republic of Croatia. In 1997, the line Bc TD3201/92 was released as the first winter durum wheat in Croatia under name Primadur.

References.

Javor P. 1984. The perspectives in selection of Zg-wheats. Agric Actuality 3:503-507.

Javor P. 1987. Work on breeding winter wheat in the Institute for breeding and production of field crops-Zagreb. In: Yugoslav Conf on conditions and possibilities of production of 6 million tons of wheat, Novi Sad. 17-18 VI, 51-60.

Koric S. 1972. A genetic analysis of the ramification factor with the wheat species Triticum vulgare and Triticum turgidum, and the action of the ramification genes by interacting on the genic complex of the species Triticum vulgare. In: Final technical report of an American-Yugoslav project, Zagreb. Project number E30-CR-233-FG-Yu-111.

Martinic-Jercic Z. 1990. Wheat in Croatia and Yugoslavia in 1990 year related on previous period. The state and future. Introductory report for the round table about the state and future in production and breeding of wheat, September, 1990, Zagreb.

Potocanac J. 1984. The breeding and genetic work on creation of wheat varieties. Results and properties of created Zg-varieties and lines. Agron J (Croatia) 6:759-786.

Tomasovic S, Javor P, Mlinar R, and Sesar B. 1993. Recent achievements in breeding winter wheat in the Institute for Breeding and Production of Field Crops-Zagreb. Agric Actuality 3-4:315-324.

Tomasovic S, Javor P, Sesar B, and Havrda S. 1995. Work on breeding hard winter wheat (Triticum durum Desf.) in Croatia. Sjemenarstvo 6:399-411.

 

Achievements of the Bc Institute­Zagreb in winter wheat breeding for resistance to Fusarium head blight in Croatia.

Introduction. In early 1970s, Fusarium head blight became a very serious disease in our growing conditions. Therefore, a breeding program looking for resistance for FHB began in 1978. Using partial diallel crosses, resistance genes were accumulated from various sources obtained through germplasm exchanges (Tomasovi 1993). New ZG-lines, resistant to FHB were developed. The new sources of resistance originated mostly from China, Japan, Brazil, and Mexico. The best materials are from China and Mexico.

Work at the Bc Institute-Zagreb on finding wheat sources of resistance to Fusarium diseases during 1976 and 1977. By 1980, approximately 870 genotypes were collected, among which 25 lines from Brazil, China, Japan, France, and Russia were the most resistant. Based on their resistance level and agronomic traits, only seven were selected for further evaluation. In 1981 and 1982, they were intercrossed and the progeny grown under conditions of artificial and natural infection in 1983. In the F1 generation, most of single cross combinations exhibited improved resistance relative to their parents. Ten double crosses had a marked improvement in resistance compared to the parents and the single crosses of the F1. Resistance genes were accumulated from various sources. The results were the first improved ZG-wheats with higher resistance to FHB. The crosses were tested in the F2 and later generations. Between 1984 and 1989, 22 combinations were selected (F3-F7) and tested as partial or complete homozygotes.

During the breeding cycle, the most resistant combinations were selected using artificial infection. The most resistant plants with valuable agronomic traits were the chosen (Mesterhazy 1990). Finally, among these, lines were selected that represent improved domestic sources with higher resistance level relative to the parents and check cultivars (Super Zlatna and Sana). This germplasm is successfully used in breeding of new ZG-wheats.

During the breeding process, the most resistant cross combinations were selected after artificial inocultion with F. graminearum. The most resistant plants with valuable economic traits were chosen. A large number of superior lines were developed with an improved level of resistance relative to the parental sources. In breeding for FHB resistance, we used our own high-yielding, high-quality cultivars, also incorporating resistance to powdery mildew, rusts, and Septoria. The results of this effort are 11 registered wheat cultivars Olga (ZG 3156/86, 1993), Sandra (ZG 2994/87, 1993), Tina (ZG 123/88, 1993), Patria (ZG 5108/89, 1994), Plodna (ZG 5059/89, 1994), Pakra (ZG 2114/90, 1995), Jela (ZG 31/91, 1996), Dora (ZG 89/91, 1996), Dinka (ZG 165/91, 1996), Posavina (ZG 2046/90, 1996), and Aura (ZG 18/91, 1997). These lines are high yielding, satisfactory in quality, and relatively resistant to FHB.

Materials and methods. Experiments were conducted in the field at Botinec between 1976 and 1996, under both natural and artificial infection with F. graminearum. Evaluations were made by an international 0-5 scale. Other diseases and relevant agronomic traits also were considered. Backcrosses were used to accumulate resistance to FHB. Diallel crosses (semidiallel) and recurrent selection also were employed (Tomasovi 1991).

Results and discussion. In the process of breeding wheat for resistance to fusarium head blight new improved Zg-sources were obtained with higher level of resistance in comparison with the initial sources and standard cultivars used in production.

In 1993, after testing under artificial infection, 36 plants were selected from 14 cross combinations. These lines had a grain yield/plant from 10-50 g, the number of grains/plant was between 80 and 911, height varied from 67-92 cm, and infection severity ranged from 0.5-3.0. Five of the selected plants from two crosses stood out (Table 2).

 

Using artificial inoculaiton, it is possible to identify the most resistant progenies with valuable agronomic characters. Preliminary and comparative small-scale trials later can select lines with improved levels of resistance to FHB. A large number of superior lines was obtained with higher levels of FHB resistance in this way. The final results of this work are 11 high-yielding, FHB-resistant wheat cultivars (Table 3). Eight of the cultivars are registered in the Republic of Croatia and three in Slovenia.

 

References.

Milatovic I, Vlahovic V, and Tomasovic S. 1982. Otpornost klasova psenice prema Fusarium graminearum Schw. Zastita bilja 33 (4) br. 1 62, 389-396 (in Croatian).

Tomasovic S. 1981. Breeding of wheat for resistance to Fusarium diseases, especially to Fusarium graminearum and creating a model for inheritance of resistance in new wheat cultivars. Genetika 13(2):177-1187.

Tomasovic S, Vlahovic V, and Milatovic I. 1983. Breeding and studying wheat for resistance to Fusarium spp., especially to Fusarium graminearum Schw. Ann Wheat Newslet 29:162-164

Tomasovi S. 1983. Poboljsanje otpornosti psenice (Triticum aestivum ssp. vulgare) prema Fusarium spp. primjenom rekurentne selekcije. Glasnik zadtite bilja 5:165-168 (in Croatian).

Tomasovic S. 1983. Problem fuzarijske paleFusarium graminearum Schw.) kod psenice. Glasnik zastite bilja 9:354-357 (in Croatian).

Tomasovic S and Vlahovic V. 1986. Head blight (Fusarim graminearum Schw.) in wheat. Ann Wheat Newslett 32:192-195.

Tomasovic S, Vlahovic V, and Matijasevi M. 1986. Investigations of the sources of resistance in wheat to Fusarium graminearum Schw. 4th Inter Wheat Conf, 2-5 May, Rabat, Morocco.

Tomasovic S. 1991. Poboljsanje izvora otpornosti novih linija psenice Triticum aestivum ssp.vulgare) na fuzarijsku paleFusarium graminearum Schw.) Ph.D. Thesis 116 pp (in Croatian).

Tomasovic S. 1993. Novi oplemenjeni ZG-izvori otpornosti psenice na fuzarioze klasa (Fusarium graminearum Schw.). Poljoprivedne aktualnosti 29(3-4):325-336 (in Croatian).

Tomasovic S, Vlahovic V, and Sesar B. 1993. Va1-2:3-24 (in Croatian).

 

Tina, Olga, and Sandra - the first winter wheat cultivars developed at the Bc Institute­Zagreb with a satisfactory level of resistance to Fusarium head blight.

Tina (Zg 123/88), pedigree 'Sana (Korona) / Gala', is a mid-early cultivar (similar to Sana). Plant height is 71-85 cm. Tina has very good to excellent resistance to lodging. At maturity, the spide is white, awnless, and cylindrical, with 21-23 spikelets/spike, and 3-4 kernels in the middle spikelets.

Tina has a high yield ability. In the 1990 trials of the former Federal Committee, the average yield across 15 locations was 7,879 kg/ha, compared to that of the check cultivar Super Zlatna at 7,317 kg/ha. The highest yield, 10,416 kg/ha, was produced at Slatina. In the 1992 trials of the Croatian Committee for Registration, the average yield across four locations was 7,079 kg/ha, compared to that of the checks Sana (6,945 kg/ha) and Zitarka (5,922 kg/ha) (see Table 4).

Kernel shape is elliptical to oval, with very good to excellent fill. The crease is mid-deep. Kernels are large, light brown, and semitransparent. 1,000-kernel weight is 43.0-49.0 g, 76-80 kg/hl. Tina is grouped in quality class II, with sedimentation values in the range of 26-36 ml at 13.11 % protein. Water absorption is 56.2 %. A quality number of 42.6 places Tina in the B1 quality group. Extensibility is 157 mm, resistance is 195 (Ej), and the relationship of R/E is 1.24.

Tina is moderately resistance to powdery mildew, leaf and stem rust, and tolerant to FHB and Septoria spp. (see Table 5). The optimum planting date is 10-25 October, at an density of 650-700 plants/m2.

Olga (Zg 3156/86), pedigree 'Zg 17/75 / Granka (Zg 3452/77)', is a mid-early cultivar, 2 days later than Sana on average. Olga has a plant height of 80-90 cm, a strong stalk, and very good resistance to lodging. At maturity, the spikes are white, awnless, and cylindrical, with 23-25 spikelets/spike and 3­5 kernels in middle spikelets.

Olga has high yielding and good stability in different growing regions. In the 1990 trial of the former Federal Committee, the average yield across 15 locations was 7,538 kg/ha, compared to that of the check cultivar Super Zlatna (7,296 kg/ha). In trial group IV, Olga produced the best yields at the Zagreb (10,172 kg/ha) and Slatina (9,856 kg/ha) locations (see Table 4).

Olga has an elongated kernel shape, with very good to excellent grain fill. Kernels are light brown and transparent. 1,000-kernel weight is 45-50 g, and 75-80 kg/hl. Olga is grouped in quality class I. Sedimentatin values are in the range of 32-45 ml at 13.00-13.57 % protein. Water absorption is 63.2 %. Olga has a quality number of 64.2 and belongs to quality group B1. Extensibility is 141 mm, resistance is 185 (Ej), and the relationship of R/E is 1.31.

Olga is moderately resistant to powdery mildew, has good resistance to leaf and stem rust, and is tolerant to FHB and Septoria spp. (see Table 5). The optimum planting date is 10-25 October at a density of 600 plants/m2.

Sandra (Zg 2994/87), pedigree 'Zg 17/75 / Roazon', is a mid-early cultivar, 2 days later than Sana on average. Sandra has a plant height between 85-90 cm, a strong stalk, and good resistance to lodging. At maturity, the spike is white, awnless, and cylindrical, with 21-24 spikelets.

Sandra is a high-yielding cultivar with good adaptability. In the 1990 trials of the former Federal Committee, from 15 locations in the V group, the highest yield of 10,124 kg/ha was produced at the Zagreb location, compared to that of the check cultivar Super Zlatna at 9,456 kg/ha) (see Table 4).

Sandra has an elongated kernel shape, transparent in consistency, and good grain fill. Kernels are light brown. 1,000-kernel weight is 47-50 g, and hectoliter weight is 76-80 kg. Sandra is most often is grouped in quality class I. Sedimentation values range between 30-43 ml at 13.00-14.50 % of protein. Water absorption is 65.7 %. Sandra belongs to the B1 quality group. Extensibility is 152 mm, resistance is 165 (Ej), and the relationship of R/E is 1.08.

Sandra is moderately resistant to powdery mildew, highly resistant to leaf and stem rust, and tolerant to FHB and Septoria spp (see Table 5). The optimum planting date is 10-25 October at a density of 600 plants/m2.

Characteristics of Patria - a new cultivar of winter wheat developed at the Bc Institute - Zagreb.

The cultivar Patria was developed from the latest breeding cycle of Bc wheats. In trials of the Registration Committee, Patria was tested during 1992 and 1993 at five locations and registered in 1994. Patria produced a higher mean grain yield in 1992 (7,360 kg/ha), an average of 5.97 % more than that of Sana (415 kg) and 24.28 % more than that of Septoria, and Fusarium). Patria is a mid-early, semi-dwarf wheat. Flour quality testing in 1993 gave a sedimentation value of 53 ml. Patria most often is classified in the quality class II and group B (see Tables 6, 7, 8, and 9 for detail).

Pakra - a new high-yielding and high-quality winter wheat developed in the Bc Institute-Zagreb.

Pakra is a new winter wheat cultivars developed from the latest breeding cycle of Bc-wheats. Pakra is a result of the continuous work on wheat breeding. In trials of the Registration Committee, Pakra was tested from 1992 to 1994 at seven locations and registered in 1995. Pakra produced a very high and stable grain yield. The highest mean grain yield was in 1992 (8,444 kg/ha), which is 7.82 % more than that of the check cultivar Sana (613 kg), a standard for grain yield, and 27.61 % more than Septoria, and Fusarium). Pakra is a semidwarf wheat, with a strong stem, and good resistance to lodging. The results of laboratory testing of grain and flour quality in 1994 show that the protein content is 14.31 %. With a sedimentation value of 36 ml, Pakra belongs to quality class II, and rarely I. With good farinograph and extensograph values, Pakra is in the high B1 group, or sometimes A2 (see Tables 10 and 11).

 

Dora - a new bread winter wheat cultivar developed by the Bc Institute­Zagreb.

Dora is a new bread winter wheat cultivar from the Bc Institute-Zagreb. Based on the results of 3-years of tests in official trials (1993-95), Dora (Zg 89/91) was registered by the Committee for Varietal Registration of the Republic of Croatia in 1996. The cultivar is intended for intensive production. Dora is a typical winter wheat with good resistance to low temperature, of medium-early maturity. The time from emergence to heading is 181.5 days, compared to that of the the check cultivars Sana (180.2) and Fusarium and Septoria. Wotj good kernel and flour quality, Dora belongs to quality class II, sometimes I, based on protein content (13.74 %) and sedimentation value (34 ml) (Zitarka has a protein content of 13.96 % and a sedimentation value of 36 ml). Dora has good farinograph and extensograph properties and is a typical bread wheat

Primadur - the first Croatian durum winter wheat (Triticum durum Desf.) developed by the Bc Institute-Zagreb.

Primadur is the first durum winter wheat in Croatia. Based on the results of 3-year tests in official trials (1994-96), Primadur (Bc TD 3201/92) was registered by the Committee for Varietal Registration of the Republic of Croatia in 1997, and was put on the list of durum wheat varieties for the pasta industry. Primadur was developed by the Department of Cereal Crops-Botinec of the Bc Institute-Zagreb for Breeding and Production of Field Crops.

With very good resistance to low temperature, Primadur is a typical winter wheat with medium-early maturity. Plant height is 80-88 cm. Straw strength is good and with very good resistance to lodging. When mature, the spikes are a deep yellow with long yellow awns, characteristic of durum wheats. Primadur has a high yield potential, above 6,000 kg/ha. Kernel filing is very good to excellent, and of the typical vitreous consistency for durum wheat. 1,000-kernel weight ranges between 45.00 and 50.00 g, and hectoliter weight varies from 76.00 to 80.00 kg. Primadur has a high degree of resistance to wheat pathogens, especially Fusarium and Septoria, to which durum wheats are considerably more susceptible than the aestivum wheats. The optimum planting date is 10-30 October, at a planting rate of 500-550 kernels/m2. Primadur was developed for intensive production.

Evaluation of wheat resistance to Fusarium head blight (Fusarium graminearum Schw.) through grain yield per plant under the conditions of artificial and natural infection.

Introduction. Diseases caused by fungi are generally one of the yield-limiting factors in wheat. Incorporating FHB resistance in wheat is very complex. Fusarium pathogens are permanently present in the soil, and as saprophytes they have very limited requirements in nutrients. In contrast, parasites cause considerable damage to crops under conditions favorable for their development (Tomasovi 1981). A severe epidemic of FHB first reported in 1975 in Croatia, was the main reason why the Institute for Breeding and Production of Field Crops in Zagreb initiated a breeding program for developing resistant varieties to this disease (Milatovi , Vlahovi , and Tomasovi 1982; Tomasovi , Vlahovi , and Milatovi 1983).

Materials and methods. Between 1976 and 1996, over 20,000 wheat