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The last several year area under soybean in Republic of Croatia constantly increase. By that, optimal crop rotation is decreased and rises incidence of different diseases of this very important file crop. This impose needs of the constant detection, identification and study of disease causal agent as well as the method of their control. Soybean (Glycine max (L.) Merr.) Diaporthe/Phomopsis complex can cause a several diseases and the three most important are: pod and stem blight, caused by Diaporthe phaseolorum (anamorph Phomopsis phaseoli) ; northern stem canker, caused by Diaporthe caulivora ; and Phomopsis seed decay, caused by Diaporthe longicolla. Southern stem canker is caused by Diaporthe aspalanthi, but this disease is still unknown in Europe. These fungi can also be involved in the root rot complex of soybeans and cause damping-off of seedlings. Beside soybeans, these pathogens could parasite numerous hosts, and some of them can cause serious economic damages in soybean production which can vary depending on climatic conditions particularly during harvest. The greatest losses usually are associated with seed decay. When wet weather delays normal harvesting, reductions of 10% in seed weight and 50% or more in seed germination are found in susceptible cultivars. Seeds infected with the fungi of this complex produce low-quality oil and flour and other value-added products, and are often unsuitable for vegetable or other food and feed uses. The aim of this work was to determinate the difference in pathogenicity among isolates of new species Diaporthe novem as well as the level of pathogenicity among these isolates in comparison to isolate of D. longicolla (causal agent of Soybean Seed Decay), which high aggressiveness was determinate in some previous investigation.

Sunflower (Helianthus annuus L.) is one of the oil crops that plays an important role in agriculture production and processing industries over the past 30 years. One of the limiting factors of sunflower growth is drought that causes stress and affects the photosynthetic activity which results in reduced plant growth and plant development. The influence of water stress on the performance index (PIABS) and maximum quantum yield of photosystem II (Fv/Fm) was studied on 13 sunflower genotypes. In the first treatment plants were maintained at 80% of the field water capacity while, in the second treatment, the field water capacity was 60%. Performance index in the first treatment ranged from 4.069 to 6.074 while values for the second treatment ranged from 3.345 to 5.817. In the first treatment genotypes 1, 3, 5, 7 and 8 showed a lower activity of the maximum quantum yield of photosystem II while in the second treatment values were higher. Genotypes 1, 8, 9 and 11 were singled out according to the values of PIABS and Fv/Fm, which may indicate higher stability of these genotypes in stressful growing conditions. These analyses can be used in the selection of sunflower genotypes with better tolerance to stress conditions.

This paper researches maximum quantum yield of photosystem II (Fv/Fm), performance index (PIABS) and leaf temperature (LT) at different soil water content (60 and 80% of the field water capacity) for 13 sunflower genotypes with the aim to determine their stability in these conditions. Also, using stress susceptibility index (SSI) we were able to determine genotype stability at different soil water content, photosynthetic efficiency parameter values and LT values. Based on the results for SSI and average Fv/Fm, PIABS and LT values, five genotypes had higher stability and tolerance for investigated traits, and two genotypes were less stable. These analyses will help breeders to select genotypes adapted to farming area. Genotype adaptability combined with the use of recommended production practices is the background for profitable sunflower production.

On each crop production, the environmental conditions (soil, weather conditions), have the highest impact. Therefore, after creation of new hybrid combinations, it is needed to check the behavior of these genotypes in different environmental conditions. With purpose of testing new sunflower hybrid combinations of the Agricultural Institute Osijek, during 2009 and 2010, field trials were sown on different localities in Croatia. In both years, trials were conducted in Beli Manastir (BM09 and BM10), Nova Gradiška (NG09 and NG10) and Osijek (Os09 and Os10), and in 2010, a trial was sown in Vukovar (Vu10) as well. These trials comprehend 3 mother cytoplasmic male sterile lines (1-3) with a set of 8 fertility restorer lines (four branching restorers: oG1-4 and four single-headed restorers: oM5-8). On grain yield data, for years and localities (7 environments), analysis of variance (ANOVA) and Additive Main effects and Multiplicative Interactions (AMMI) analysis by statistical software SAS for Windows 9.1 were made. In order to better oversight grain yield stability of different hybrid combinations in different environments, AMMI1 and AMMI2 biplots were made by IRRISTAT for Windows 5.0 software. Between hybrid combinations of mother lines (1-3), statistically significant differences were not found. Among analyzed environments, statistically significant the highest grain yield was realized in the environment Os09 (4.220 t ha-1), then in BM09 and Os10. The highest grain yields, statistically in the same rank, had hybrid combinations with oG2 and oM7 restorers (3.726 and 3.666 t ha-1). By accumulation, first two Interaction Principle Components (IPC) explain 85.4, 76.6 and 64.8 % variability for crosses cms1, cms2 and cms3 lines. AMMI1 and AMMI2 biplots were shown that the highest yielded hybrid combinations had not the most stabile grain yield. The highest stability is shown in restorer line oM7 in cross combinations with cms1 and cms 2 lines (inbred lines), while the same restorer line in crossing with cms3 line (sterile single-cross) had a large genotype x environment interaction, respectively low stability.

The experiment was set up as split-split plot method with three repetitions in two vegetation seasons (2006-2007) in order to determine the influence of irrigation treatment (A1-control, A2- 60% to 100% field water capacity (FWC), A3-80% to 100% FWC), N fertilizer (B1-control, B2-100 kg N ha-1, and B3-200 kg N ha-1) and genotype (C1= OSSK 596 ; C2=OSSK 617 ; C3= OSSK 602 ; C4 = OSSK 552) on yield and yield parameters (cob lenght, cob weight, kernel number, kernel weight and number of rows per cob) of maize. Irrigation treatment have very signifcantly increased yield in both tested years. Also, irrigation treatment increased row nubmer/cob, kernel weight (KW), kernel number (KN), cob weight (CW), (P>0.05) in 2006, CW and KN in 2007 (P>0.01). N fertilization had a very significant (P>0.01) impact on all testeted factors in both years of research. Genotype showed very significant impact on all tested factors in year 2006, although in dry vegetation season 2007 statistical singficant was showed only to yield and kernel number.

Under field conditions in Osijek during two years were set field trials. The aim was confirm an influences of irrigation rate, nitrogen (N) fertilization and soybean varieties on grain yield and some yield components. The irrigation treatments were: control (A1) ; soil moisture content from 60% to 100% retention water capacity (RWC, A2) and soil moisture content from 80% to 100% RWC (A3). Rate of N was sub sub-factor: 0 (B1) ; 100 (B2) and 200 kg N ha-1 (B3), were applied. Una (C1) and Anica (C2) soybean varieties was sub-sub factor (C). Mean soybean grain yields were 3082 kg ha-1 and 3538 kg ha-1 in years 2006 and 2007, respectively. Irrigation resulted by high statistically difference in soybean grain yield in both investigated years and between all treatments. Variety Una yielded (3179 kg ha-1) statistically very higher in 2006. Interactions AB, AC and BC on pod number plant-1 were significant in one year, only. Thousand grain weight (g) resulted with high significant higher value on variety Una than variety Anica in both years. N fertilization resulted by statistical very significant effect of grain weight plant-1 in year 2007, while variety Una resulted by statistically very significant higher grain weight plant-1 than variety Anica in year 2006. Interactions AB and BC showed statistically very significant or significant differences in grain weight plant- 1. Irrigation (in year 2007) and N fertilization (in year 2006) had significant different number of grain plant-1. Variety Una had statistically very significant higher number of grain plant-1 than variety Anica in year 2006, only. Interactions AB and AC were shown statistically very significant differences in number of grain plant-1, in year 2007, but BC interaction were in both years.

Influences of irrigation rates (A1= non- irrigated, A2 = irrigation starting on level of 60% field water capacity or FWC ; A3 = irrigation starting on level of 80% FWC), nitrogen (N) fertilization (0, 100 and 200 kg N ha-1, for the B1, B2 and B3, respectively) and genotype (maize hybrids: OSSK 596, OSK 617, OSSK 602 and OSSK 552) on oil content in maize grain were tested under field conditions on Osijek eutric cambisol during four growing seasons (2006-2009). Depending on the year, oil contents in maize grain were in ranges from 3.44% to 4.20%, irrigation effects resulted by non-significant differences, N fertilization increased oil contents only in 2007 (3.54% and 3.66%, for the control and B3, respectively), while differences among the hybrids were mainly significant but under considerable environmental influences.

In this paper we present results on the influence of desiccation on laboratory germination and field emergence of sunflower hybrid Favorit and its parental lines. As desiccants we used Reglone forte [diquat] (3 l/ha) and Harvade 25F [dimethipin] (2 l/ha), with water usage of 500 l/ha. Desiccation was done on August 20, 2006, and, after 20 days, the genotypes were harvested. In each trial variant (combination of genotype and treatment) laboratory germination was performed on four subsequent dates with 2-month intervals. With relation to the control, the Harvade 25F variant had a statistically significant higher germination of 4.38%, while the Reglone forte variant had a statistically significant higher germination in relation to both, control and Harvade 25F, of 7.32% and 2.95%, respectively. Regarding field emergence, differences among the treatments were small, statistically non-significant. Like in the laboratory germination test, Reglone forte treatment had the highest field emergence (78.55%) which was higher than the control and Harvade 25F in 2.94% and 2.86%, respectively.

Sunflower (Helianthus annuus L.) is main field crop for edible oil production in Croatia. Environmental factors have a great influence on sunflower production, especially amount and distribution of precipitations during the vegetation period, what proving three-year results of sunflower macro trials at Sopot (PIK Vinkovci d.d.). Among analyzed years, 2005 was distinctly weather unfavourable year for sunflower production. In this research are presented results of eight commercial sunflower hybrids from different breeding companies (Heliasol, Apolon, PR63A90, Opera, LG 5385, Favorit, Fleuret and NS-H-111) in macro trials at Sopot (2004-2006) as well as in micro trial (2005) at the Agricultural Institute Osijek. In 2005 macro trial, grain yield and oil content were remarkably less in respect to 2004 and 2006, what resulted in reduced oil yield in 2005 for about 60% in 2004 and 2006 respectively. In micro trial, alongside before harvesting, on heads of 100 successive plants, pathogens Sclerotinia sclerotiorum and Botrytis cinerea are visually estimated. Heliasol and PR63A90 showed the highest tolerance to these pathogens. Plant height over 200 cm had PR63A90 and NS-H-111 (220 and 219 cm), while the largest head diameter NS-H-111 (22 cm). The largest hectoliter mass had Apolon, Heliasol and Opera (41.2, 39.5 and 39.5 kg), and mass of 1000 grains Fleuret, LG 5385 and Favorit (67.0, 63.6 and 62.4 g). Oil content over 50% in dry matter had Apolon, Heliasol, LG 5385 and Opera (52.30, 51.81, 51.54 and 50.12%). Fatty acids were determined by gas chromatography. The highest content of linoleic acid has Apolon (72.6%), then PR63A90 and Heliasol (71.6 and 70.6%). Towards content of oleic acid, NS-H-111 has 25.4%, and then follow LG 5385 (25.0%) and Fleuret (24.7%). The highest content of stearic acid has Favorit (4.8%), and then follows Fleuret (4.2%). PR63A90 has the highest content of palmitic acid (6.5%), followed by Favorit (6.1%).

The composition of the triacylglycerols is a characteristic of plant species and has nutritional, biochemical and technological importance. The oil from commercial soybean cultivars, corn and sunflower hybrids were extracted with diethilether contained buthyhidroxytoluene. The triacylglycerol compositions of oils were determined by reversed-phase high-performance liquid chromatography with refractive index detection. Triacylgylcerol were separated based on equivalent carbon numbers and were identified by comparing their retention time to standards. A total of 17 peaks were separated from injected oil sample and quantified based on relative percentage peak area. The main triacylglycerols (> 5%) in oils were trilinolein, dilinoleolein, dilinoleopalmitin, linoleodiolein, dilineostearin, linoleoleopalmitin and linolenodilinolein. The other minor triacylglycerols (< 5%) were linolenolinoleopalmitin, linoleodipalmitin, triolein, linoleoleostearin, dioleopalmitin, dioleostearin, dilinolenolinolein, dipalmitolein, trilinolenin, dilinolenolein and oleopalmitostearin. The main triacylglycerols represented in sunflower oil 88.14%, in corn oil 82.19% and in soybean oil 77.41% of total triacylglycerols. The differences between triacylglycerols composition within and between cultivars were calculated by analysis of variance. Significant differences (P

Over the period of 11 years (1997-2007), macro experiments with sunflower hybrids were set up at the location of Vinkovci. The experiments included hybrids of recognized world companies, from 13 to 30 per each test. During 11 years, the average head diameter, stem height, disease incidence of Sclerotinia sclerotiorum, grain yield, oil yield and oil content were recorded for each hybrid. The highest plant height was recorded in 1997 and 1998 (204 cm), while the lowest plant height was observed in 2006 (169 cm). Average plant height throughout the experiments was 188 cm. Head diameter ranged from 18.1 to 22.9 cm, averaging 19.6 cm. The greatest incidence of white rot disease (Sclerotinia sclerotiorum) occurred in 2005 (39.6% of infected plants). The average grain yield was 3 t ha-1 and it varied from 1.13 t ha-1 in 2005 to 4.56 t ha-1 in 2000. The oil content was between 42.05 and 48.17%, with an average over experiments of 44.42%. The lowest oil yield was obtained in 2005 (0.49 t ha-1) and the highest in 2000 (2.04 t ha-1), with an average of 1.31 t ha-1.

Sunflower breeding programs in the Republic of Croatia have over 30-year tradition, and they be realized through different scientific projects and programs in frame of the Agricultural Institute Osijek (Mijic et al., 2004 ; Krizmanic et al., 2005). Main goal of this program is creation of new superior hybrid with high grain yield (above 5 t/ha), oil content (above 50%) and high and stabile oil yield. Special attention is given to creation of lines with emphasized tolerance to dominant pathogens. Sunflower breeding on resistance/tolerance to main diseases is the best way to control them and environmentally friendly as well (Fick and Miller, 1997 ; Miller and Fick, 1997 ; Skoric et al., 2002 ; Vrataric and Sudaric, 2004). This field inbred lines testing as well as the later investigation in biotechnological laboratory will contribute to higher efficiency of sunflower breeding program by choosing more tolerant lines to creation of new hybrids. Investigation was conducted during 2005 at the Agricultural Institute Osijek experimental fields on 30 trial members. Twelve cytoplasmatic male sterile (CMS) inbred lines (L-97 A, L-193 A, L-115 A, G/04 A, L-301 A, L- 189/II A, L-101 A, L-13 A, L-205/II A, L-205 A, L-81 A, L-83 A), seven sterile single-crosses (possible mother component for three-way hybrids) (G/03 A x L-104 B, G/03 A x L-14 B, G/03 A x L-282 B, G/03 A x L-272 B, G/03 A x L- 102 B, G/03 A x L-190 B, G/03 A x L-302 B), five male fertile lines (L-14 B, L-272 B, L-16 B, L-302 B, L-190 B), four restorer-fertility lines (PI 12/99 R, O3G R, RFS-89 R, O3 MR) as well as two recently recognized hybrids (Favorit and Apolon), all selected at the Agricultural Institute Osijek, Croatia, were used in this study. Each line was sown in two 5 meter long rows and 3 replications. One row of each line was control and the other served for artificial infection. In each replication 7 plants of each line was artificial inoculated in a button stage (R2 according to Schnieter and Miller, 1981). Sunflower stems were inoculated on 7th July by parts of sclerotia originated from sunflower and collected year 2004 at the location around Osijek. Peaces of sclerotia (around 0.5 cm in diameter) were incorporated into holes on stems made by penetration of wooden sharp pencil. After we put sclerotia into a hole, wound was closed by peace of wet cotton and aluminium foil (Vasic et al., 2004). The infection is evaluated three times after inoculation by measuring length of lesions on stems. First evaluation is done one week after inoculation, second two, and a third and final measurement three weeks after inoculation. Analysis of variance (ANOVA) and LSD test were processed by Statistical Analysis System Version 8.2 (SAS Institute). Data were previously tested for a normal distribution. The smallest lesion was recorded for cytoplasmatic male sterile line L-83 A. Also, L-190 B (male fertile line) and O3 MR (restorer-fertility line) according to measurements belong to group of more tolerant lines in comparison to other 24 trial members including recognized hybrids Apolon and Favorit. These three lines could be possible parental lines for creation of one a new hybrid which will be possibly more tolerant to white mold, at least in comparison with these two recognized hybrids used in trial. This could be further investigated in some new trials. However, it is important to point-out that this hybrid maybe could not have desirable other important agronomic traits such as high and stabile grain and oil yield, 1000 seed weight, plant height, head diameter, etc.

The study was aimed to examine the changes in seed vigor and oil content in different genotypes of maize, soybean and sunflower over four years (2002-2006) in two type storage conditions differed in terms of air temperature and humidity: 25 C/75% and 12 C/60%, respectively. Affected by storage longevity, on an average, seed vigor decreased for 18, 7% in maize and for 57, 1% in both soybean and sunflower, respectively. Seed oil content decreased for 1, 12% in maize, 2, 27% in soybean and 12, 05% in sunflower. Differences in seed vigor and oil content affected by storage longevity were significant among tested crops and genotypes into crop. Storage longevity was negatively associated with seed vigor and oil content. At storage conditions by 12 C/60%, decline of seed vigor was less for 17% (maize), for 24% (sunflower, soybean)and decreasing of seed oil content was less for 0, 87% (maize, 0, 91% (soybean)and 2, 27% (sunflower) than in storage conditions by 25 C/75%. In summary, the lowest seed quality losses were in maize, then in soybean and the highest losses were in sunflower. Decreasing seed quality losses is possible with providing suitable storage conditions, particularly for soybean and sunflower.

Within the sunflower breeding program of the Agricultural Institute Osijek, each year is created some few hundred of new hybrid combinations. The best combinations passing through the net of micro and macro trials on different locations in more years. In one of those researches were five registered hybrids (Apolon, Favorit, Olio, Fakir and Orion), and two experimental hybrids ((189A x 5B) x O3 and 219A x O3). The field trials were set up towards a completely randomized block design in 2002 and 2003 year, on the three locations in the Republic of Croatia (Osijek, Karanac and Feričanci). Six traits of the sunflower hybrids were analyzed: plant height, mass of 1000 grains, hectoliter mass, grain yield, oil content and oil yield. Shorter plant height had hybrids Apolon and Favorit. The largest values of 1000 grain mass had hybrids Orion, then Fakir and Olio, and the highest hectoliter mass had Apolon, then Favorit and Olio. By grain yield were pointed out hybrids Fakir, Apolon and 219A x O3, and for oil content Apolon, (189A x 5B) x O3, Favorit and 219A x O3. The largest oil yield had hybrid Apolon (2107 kg/ha), then 219A x O3 (1951 kg/ha), and Fakir (1931 kg/ha). Beside that were analyzed direction and strength of connection among above mentioned traits and oil yield. Among mass of 1000 grains and oil yield as well as hectoliter mass and oil yield were found very low positive correlation. Between plant height and oil yield correlation was medium positive, and only among grain yield and oil yield is established completely positive correlation.

In the paper are presented results of the OS sunflower hybrids in two very different years regarding rainfall and air temperature. In 2002 year, amount of rainfall and air temperature were optimal, but in 2003 is recorded unprecedented drought during the vegetation period and heavy hailstorm on the beginning of July that caused a huge damages of hybrids on the experimental field of the Agricultural Institute Osijek. In the research were analyzed: plant height, mass of 1000 grains, grain yield, oil content and oil yield. Based on the analyzed traits, results in 2002 year were significantly better in comparison to 2003 year. The OS sunflower hybrids were shown a high potential for grain yield, oil content and oil yield as well as emphasized drought tolerance. In conditions of significant leaves, stem and head damages by hailstorm, our hybrids have realized the satisfy results.

The objective of this research was to estimate general (GCA) and specific combining ability (SCA), and gene effect for grain yield of sunflower, to determine variation in phenotypic variance, to compare two-line and three-line hybrids where two-line hybrids were mother's components, and to find out prospective parental lines and hybrids. In 1998, by diallel crossing 6x6 without reciprocals seed of created 15 two-line hybrids was obtained. Next year, hybrids were sown in field trials at Osijek and Đakovo (Croatia). The fertility restorer line was sown around each trial. In 2000, 15 three-line hybrids obtained from the previous year, and three commercial hybrids of the Agricultural institute Osijek were sown at the same locations. Between two-line and three-line hybrids, significant differences were found for analyzed trait at both locations. The largest effect of GCA for grain yield had OS-1 line at both locations and OS-3 line at Đakovo locality. Only in Đakovo were found significant differences for SCA. The best combination was OS-3 A x OS-6 B. Portion of genetic in comparison to the environmental variance in the phenotype variance for grain yield was larger. Additive part of genetic variance had larger influence on inheritance of grain yield. Between tested hybrids in 2000 year, only H-4 hybrid [(OS-1 A x OS-5 B) x RF-28] in Osijek and Fakir in Đakovo had significantly higher values than control hybrid Orion.

Thirty-five Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System Beta collection were screened for resistance to Cercospora beticola Sacc. at three locations: 1) an artifically produced epiphytotic in Windsor, CO. ; 2) an artifically produced epiphytotic in Osijek, Croatia ; and 3) naturally occurring epiphytotic in Osijek, Croatia. These accessions included sugar beet, leaf beet, garden beet, fodder beet accessions (Beta vulgaris subspecies vulgaris), as well as wild sea beet accessions (Beta vulgaris subspecies maritima). Randomized complete-block designs, with two replications were used to evaluate germplasm. Internal controls included a highly susceptible synthetic check and a resistant hybrid check, (FC504 x FC502/2) x SP6322-0. The artificially inoculated nurseries were inoculated twice. The PIs were visually evaluated on a scale from 0 (no disease) to 10 (plant dead). In Colorado, the leaf spot epidemic progressed rather slowly at first, but rapidly became quite severe by late August to early September. The growing season in Croatia is about one month ahead of Colorado, therefore the trials in Croatia were evaluated earlier. The inoculated nursery in Croatia also had severe disease symptoms. Because some of the annual B.v. subsp. maritima accessions flowered very early in Croatia, they could not be evaluated, and there are complete data (all three locations) available on only 19 of the accessions. An analysis of variance (PROC ANOVA - SAS) on the disease indices (visual evaluation scores) determined that there were significant differences among entries (P=0.05) on all three dates at all three locations. An LSD was generated for mean separations. Although the variation was higher in Osijek, susceptible and resistant controls performed similarly. Some entries, however, which showed resistance in Croatia, were moderately to highly susceptible in Colorado.

Thirty-five PIs (Garden Beet, Sugar Beet, Leaf Beet, Fodder Beet, and wild beet) were screened at three locations: 1) an artificially produced epiphytotic (Ruppel, E.G., and J.O. Gaskill. 1971. Techniques for evaluating sugarbeet for resistance to Cercospora beticola in the field. J. Am. Soc. Sugar Beet Technol. 16: 384-389) in Fort Collins, CO ; 2) an artificially produced epiphytotic in Osijek, Croatia ; and 3) a naturally occurring epiphytotic in Osijek, Croatia. Randomized complete-block designs, with two replications were used to evaluate germplasm. Internal controls included a highly susceptible synthetic check and a resistant hybrid check, FC (504x502/2) x SP6322-0. Two-row plots were 4 m long, with 56 cm between rows and 20- to 25-cm within-row spacing. The artificially inoculated nurseries were inoculated twice, on 13 and 23 June in Osijek, and on 27 June and 8 July in Fort Collins. Visual evaluations on a scale from 0 (no disease) to 10 (plant dead) of PIs in the natural and artificial Cercospora epiphytotics were made in Croatia on 8, 18, and 28 Aug. Evaluations in Fort Collins were made on 2, 9, and 16 Sept, with the peak of the epidemic occurring on or about the last date. This project was supported by the USDA-ARS NPGS and USDA/FAS/RSED grant HR02. In Fort Collins, the 1997 leaf spot epidemic progressed rather slowly at first, but rapidly became quite severe by late August to early September. At our third evaluation, means of the resistant and susceptible internal controls were 3.7 and 7.3, respectively, across all trials in the nursery. An analysis of variance (PROC ANOVA - SAS) on the disease indices (visual evaluation scores) determined that there were significant differences among entries (P=0.05) on all three dates at all three locations. An LSD was generated for mean separations. Although the variation was higher in Osijek, some entries performed very differently at the different locations.

Satisfactory root yields and low sucrose contents characterize sugar beet production in Croatia. We studied about the possibility of improve sugar beet quality, especially sucrose contents, by application of MgSO4, because shortage of Mg could be a limiting factor of sugar beet root quality. Testing of sugar beet hybrids (total 19) were performed on three localities of eastern Croatia for the 1997 growing season. The field trials were conducted in eight replications. Each experimental plot measured 10 m2 (two 10-m rows). Four replications (total 228 plots) were treated with Epsom salt (5% MgSO4 . 7H2O solution ; 400 l/ha) two times in eight days interval (June 9 and June 17, 1997). The growing season 1997 was especially favorable for sugar beet growing. Epsom salt fertilization (ESF) significantly influenced on digestion (15.18% and 15.44%, for control and ESF, respectively), sugar beet root yields (55.16 and 57.38 t/ha, respectively), sugar yields (7.12 and 7.52 t/ha, respectively) and root K contents (3.83 and 3.95 mmol/100 g of root, respectively). However, sodium (Na) and amino-N contents were independent on ESF treatments. Differences among hybrids were in range from 14.81 to 16.00% (sucrose), from 49.48 to 60.54 t/ha (root yield) and from 6.18 to 8.23 t/ha (technological sugar yield), from 3.47 to 4.48 mmol/100g root (potassium), from 1.09 to 1.56 mmol/100g root (sodium) and from 2.00 to 2.96 mmol/100g root (amino-N). By our testing for the growing seasons 1995 and 1996, mean sucrose contents increased as affected by Epsom salt fertilization for 0.25% and 0.20%, respectively. Based on our 3-year experiences, we suggested foliar spraying of sugar beet with Epsom salt as usual crop management practice, especially on soils with moderate Mg supplies.

Sugar beet growing area in Croatia is relatively small (28 568 ha or near 2% of arable land capacity: state of 1991). It is mainly situated in the eastern part of the Pannonian region because of better soil characteristics. However, some soil types are less favourable for crop growing because of nutritional stress (for example, highly K-fixing gleysols). For this reason, enormous K rates even up to 3 250 kg K2O/ha were applied in the field trial. In general, sugar beet was shown as tolerant crop concerning soil stress induced by K-deficiency and Mg-oversupply because favourable yields were found in the control treatment (2-year mean: 55.40 t/ha). The application of high K rates increased root yield for about 30% and also improved its quality, especially of sugar yield. Response of maize and soybean to K-fertilization was considerably higher because their grain yields were especially low under conditions of ordinary recommended fertilization.

The aim of this paper was to research physiological sugar beet seed properties (Beta vulgaris L.) considering seed largeness. The research was being carried out in 1993 and 1994 by using seed of native Os Nada hybrid. This investigation comprised factors which directly affected seed germination as well as yield and quality of sugar beet root. For this purpose the seed was divided into four fractions. After that the speed of water absorption in the swelling process was determined as well as germ lengh and weight, germination dynamics, field germination dependence on seed largeness and sowing depth. It was determined that by sugar beet fruits largeness increasing, absolute weight and germination also were increasing, whereas monogermity was decreasing. Water reception speed was higher with small fruits and smaller fractions seed began to germinate earlier. As the result of the above mentioned, after 5 days germination germs of higher lenght and weight were measured with small seeds in reference to germs from large seeds. The highest field germination was 77% achieved with the largest seeds (over 5.5 mm) at the sowing of 2-3 cm depth. By sowing depth increasing, field germination was decreasing. Germination decreasing was significantly faster with small fractions. Statistically justified the highest sugar yield (above 4 t/ha) gave the variants with seed larger than 3.5 mm at the sowing depth of 2-3 cm and the variant of the largest seeds (above 5.5 mm) at sowing depth of 3-4 cm.