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• The response of sunflower hybrids to different plant densities on a chernozem soil

  123-128

  Adrienn Novák

  András Szabó

  Péter Pepó

  Views:

  147

  In our experiment the reaction of six sunflower hybrids of different genotypes (NK Oktava, ES Biba, ES Diagora, ES Ballistic, EGH 8925, PR 64 H 42) towards plant density has been investigated by different fungicide treatments in the crop-year of 2011 on a chernozem soil. 
  In the crop-year of 2011 sunflower populations were infected by a significant Diaporthe helianthi disease. The extent of this infection was significantly enhanced by the increment of plant density. However, regarding the average of the hybrids and plant densities the two times executed fungicide treatment has decreased the infection rate by 22%. The most susceptible hybrid was the ES Biba. Contrarily, the hybrid ECH8925 proved to be the most resistant hybrid towards this
  disease according to our results. According to the results of the Pearson’s correlation analysis it has been revealed that stalk breakage and Diaporthe infection stand in a very close (r=0.782**) and middle close (r=0.523**) correlation resp. with plant density. The relationship between fungucude treatments and stalk breakage, just as Diaporthe infection showed to be middle and close respectively. Our results demonstrate the role of stalk and plate diseases (among them Diaporthe) in causing stalk breakage, for we have found a close positive correlation between stalk breakage and Diaporthe infection (r=0.624**) in our analysis.
  From the aspect of yield amount the optimal plant density varied between 45 000 and 55 000 plants per hectare. Fungucude treatments enabled not only the use of higher plants densities, but they had a yield increasing effect as well. In the crop-year of 2011 the highest yield (4 559 kg ha^-1) on a chernozem soil has been measured in case of the hybrid ECH8925.

• Effect of the crop-year on plant protection feature of sunflower

  71-75

  Adrienn Novák

  Views:

  156

  Our study focused on plant density reactions of sunflower hybrids on chernozem soil in years with different levels of available water (2011 and 2012). We studied factors (i.e.infections, yield) that are most affected by the amount of precipitation.

  However the amount of precipitation varied in 2011 (average amount of precipitation) and 2012 (drought), Sclerotinia and Diaporthe infections were significant in both years. Diaporthe was stronger in 2011 while in 2012 Sclerotinia infections were greater than average. Higher plant density provided for a favorable microclimate for pathogens meaning that increased stock density enabled enhanced infections. Maximum levels of infections in both the cases of Diaporthe and Sclerotinia were measured at a plant density level of 65 000 plants ha^-1.

  2012 yields (control: between 2 289 and 3 261 kg ha^-1, two-time treated: between 2 699 and 3 659 kg ha^-1) were significantly lower compared to the results of 2011 (control: between 2 825 and 3 672 kg ha^-1, two-time treated: between 3 059 and 4 059 kg ha^-1). Fungicide treatments led to an increased yield in both years: 9.5% in 2011 and a notable, 15.1% growth in 2012. We applied regression analysis to calculate optimum plant density for the examined years and treatments. Based on the calculations we found that in the cases of both treatments optimum plant density was 53 000 plants ha^-1, while in 2012 the optimum was higher due to lower level of infections: 56 000 plants ha^-1 in the control stock and 64 000 plants ha^-1 in the stock treated twice.

• Examining reaction of sunflower genotypes on planting time on chernozem soil

  93-99

  Adrienn Novák

  Views:

  104

  We studied the effect of planting time on plant pathological factors, leaf area index and yield production by applying various fungicid treatments on two different sunflower genotypes in 2013.

  By delaying planting time, both the extent of Diaporthe, Alternaria and Phoma infections decreased. The differences between the volume of infections were significant in the case of the early and late sowing time results. The application of fungicide treatments induced a notable decrease in the extent of infections for all three pathogens examined. The LAI-values varied between 0.3 and 5.6 m²/m² in 2013 depending on the hybrid, sowing time and treatment. Stocks planted at distinct times reached maximum leaf coverage at different times. The planting time and the fungicide treatment had a significant effect on the formation of the leaf area. In the case of average and late planting times, fungicide treatments elongated the preservation of the green leaf area.

  With respect to the yield amount, average planting time (27 April, 2013) turned out to be optimal in 2013 (control – NK Ferti: 4.621 kg ha^-1, PR64H42: 4.196 kg ha^-1; double-treated: NK Ferti: 5.282 kg ha^-1, PR64H42: 5.090 kg ha^-1). Fungicide treatments resulted in significant yield growth in all cases during our research.

  We applied Person correlation analysis to evaluate the hybrids’ sensibility to infections and our results varied in the case of Diaporthe and Phoma (r=-0.343*, -0.379**). Infections of the three pathogens were significantly reduced by delaying the planting time and applying fungicides. Late sown stocks preserved the green leaf area for a longer period. Besides, the application of the fungicide treatment and the hybrid itself also led to the preservation of the green leaf area. However, pathogens examined notably decreased the leaf area by the end of the growing year. The fungicide treatment had a remarkable effect on yield growth (r=0.603**). Furthermore, the presence of higher LAI-values in the period prior to August also induced higher yields.

• The effect of the sowing time on the yield and oil content of sunflower (Helianthus annus L.) in different crop protection models

  57-61

  Adrienn Novák

  Views:

  130

  The field research was carried out at the experimental farm of the University of Debrecen at Látókép on calcareous chernozem soil in Hungary. We examined the effects of the sowing time and the fungicide treatment on the yield, oil yield and oil content of two different genotypes of sunflower hybrids (NK Ferti, PR64H42) in 2012 and 2013. We applied three different sowing times (early, average, late) and two different treatment levels of fungicides (control =no fungicides applied, double fungicide protection).

  During our research, we received better results in 2013 than in 2012. The application of different planting times affected the yield and oil yield production and the oil content as well. The optimal circumstances for yield and oil yield production were provided by late planting in 2012, while by average planting time in 2013. The highest oil yield results were reached by late plating in both years (except for hybrid PR64H42 in the double treated parcels where average plating time turned out to be more effective). The correlation between the plating time, the yield and oil yield production and the oil content was strong in 2012 (r=0.600**, r=0.639**, r=0.590**). On the other side, in 2013, the correlation was medium between the planting time, the yield production and the oil content.

  We applied Pearson’s correlation to analyze the effect of the double fungicide treatment on the yield and oil yield production (2012: r=0.498**, r=0.407**). These results were better in 2013 (r=0.603**, r=0.623**), besides, the double fungicide treatment also increased the oil content (r=0.315**).