Bc INSTITUTE FOR BREEDING AND PRODUCTION OF FIELD CROPS
d.d. Zagreb, Marulicev trg 5/I, 10 000 Zagreb, Croatia.
Slobodan Tomasovic, Rade Mlinar, Ivica Ikic, and Kristijan Pusaric.
Introduction. Wheat cultivars of the Bc Institute are regularly tested every year in a network of large-scale trials throughout Croatia covering all major production areas. Cultivars developed by local breeding companies and introduced foreign cultivars also are tested in these trials. The objective was to compare yield data from 2001 and 2002 from two groups of cultivars developed by the Bc Institute: the standard cultivars (Marija, Sana, Patria, Tina, and Liberta) and more recently developed cultivars (Zdenka, Mihelca, Aura, Lana, Nina, and Prima). Results of milling and baking quality tests of Bc wheats also were compared.
Materials and methods. The 2-year yield data covers the mean of each year (2001 and 2002). These data were obtained from locations in Belje, Vinkovci, Osijek, Nasice, and Koprivnica. Mean values for milling and baking quality parameters (grain and flour quality) were obtained from large-scale trials at Vinkovci, Belje, Kutjevo (the mill in Pozega), and Koprivnica (the mill in Podravka).
Results and discussion. The 2-year yield data of Bc wheat cultivars show that the average yield of the standard cultivars was 7.15 t/ha and 7.23 t/ha for the current cultivars in 2001-02. The standard cultivars produced an average grain yield of 7.22 t/ha in 2001 and 7.12 t/ha in 2002; a slight reduction in 2002. Newer cultivars had an average grain yield of 7.34 t/ha in 2002, which is an increase compared with the average grain yield of 7.12 t/ha in 2001. When compared individually, similar yields were obtained by Tina, Marija, and Sana among the standard cultivars, whereas among the newer cultivars, Prima (7.7 t/ha) and Nina (7.35 t/ha) stand out. These cultivars had the highest individual yields (Figs. 1 and 2).
By comparing the averages of the milling and baking properties of both sets of cultivars developed by the Bc Institute, improvement of flour and bread quality was achieved in the newer cultivars. Better results were obtained for the most important quality parameters (wet gluten, softening, quality number and group, dough energy, O/R, and falling number) by the more recent cultivars when compared with the standards, especially for Zdenka, Mihelca, Aura, and Lana, which are classified by their properties as quality bread wheat (Tables 1 and 2).
Conclusion. Testing standard and more recent Bc wheat cultivars in large-scale trials in the Republic of Croatia proved that progress made in our breeding programs has been the result of development of winter wheat genotypes with high and stable yields and improved grain, flour, and bread quality.
Acknowledgment. Data from the following producers were used: Belje d.d., PIK Vinkovci d.d., IPK PZC Osijek, Kutjevaki podrum d.d., HANA d.d. Nasice, and Podravsko gospodarstvo Koprivnica.
Slobodan Tomasovic, Branko Palavercic, and Rade Mlinar.
Fusarium head blight is one of the most important diseases in winter wheat world wide (Cvjetkovic et al. 1987; McMullen et al. 1997; Wang and Miller 1987; Wiese 1987). Besides reducing yield, FHB affects grain quality due to the formation of the mycotoxins deoxynivalenol and zearalenone (Miller and Trenholm 1994). Breeding for resistance and growing of resistant cultivars is, in terms of ecology, the best means of FHB control in wheat. Breeding involves reliable methods of artificial infection, screening of the infection, identification of sources of resistance, and incorporation of resistance into adapted genotypes. Our objective was to compare two media for production of F. graminearum spores. We compared the inoculum produced on solid potato-dextrose agar and a that from a modified Bilay's liquid medium (Reid et al. 1996). Two field trials with five replications were conducted involving 18 wheat cultivars including three sources of resistance (Tomasovic et al. 1993; Tomasovic 1997). Artificial infection was made at three intervals beginning when 50 % of the spikes were flowering. Inoculum was prepared from three F. graminiarum isolates. Their pathogenicity was checked according to Mesterhazy (1984). The percentages of disease incidence and severity were estimated on spikes in the field after inoculation. Visual indices were calculated (percentage of incidence x percentage of severity/100) (Gilbert and Morgan 1999). In both trials, significant differences in the visual rating index between wheat cultivars were obtained regardless of the kind of inoculum. The cultivar Poncheau was the best source of resistance compared to the two other sources, (D 48 x 42 x 6)2 and Roazon, although Roazon possesses valuable agronomic characters. We should emphasize that the agronomically valuable cultivars Bc 5792, Bc 5210, and Bc 733 have high resistance to FHB and can be used as controls (Table 3). Regardless of the medium used for inoculum production, wheat varieties were differentiated by their resistance (r = 0.78). Differences in the level of resistance were observed for Bc 5108, Bc 4685, and especially for Bc 165 depending on the inoculum used. In both trials, the varieties Bc 5792, Bc 5210, Bc 733, Bc 163, and Bc 18 were significantly superior compared to the relatively susceptible lines Bc 165, Bc 6152, Bc 123, Bc 6881, and Bc 6161. Nevertheless, by using the liquid medium, slightly higher than average infection rates were obtained, and the varieties could be distinguished better with the visual rating index. Due to abundant sporulation, the modified Bilay's liquid medium is suitable for the rapid production of F. graminearum inoculum and is recommended in breeding for resistance to FHB.
| Cultivar | Experiment 1 | Experiment 2 | ||
|---|---|---|---|---|
| VRI | PDA | VRI | MB | |
| Poncheau | 0.0 | ++ | 0.1 | ++ |
| Bc 5792 | 1.4 | + | 2.4 | ++ |
| (D48 x 42 x 6)2 | 1.8 | + | 2.0 | + |
| Bc 5210 | 2.2 | + | 3.8 | + |
| Bc 733 | 3.8 | + | 2,7 | + |
| Bc 163 | 2.4 | + | 6.1 | + |
| Roazon | 3.0 | + | 5.0 | + |
| Bc 18 | 3.6 | + | 5.8 | + |
| Bc 5108 | 2.8 | + | 6.8 | ~ |
| Bc 845 | 7.8 | ~ | 7.3 | ~ |
| Bc 5887 | 8.3 | ~ | 7.8 | ~ |
| Bc 6601 | 8.8 | ~ | 8.0 | ~ |
| Bc 6161 | 11.6 | --- | 14,5 | --- |
| Bc 4685 | 10.1 | ~ | 20.0 | - |
| Bc 6881 | 12.8 | --- | 24.3 | - |
| Bc 123 | 14.8 | --- | 32.0 | - |
| Bc 6152 | 25.0 | - | 27.5 | - |
| Bc 165 | 46.5 | - | 19.3 | --- |
| Mean | 9.3 | 11.0 | ||
References.