Given that climate change is a burning issue, agriculture must turn to more sustainable and environmentally friendly systems, counting intercropping. Within a two-year study of intercropping sunflower with legumes, the influence of this system on sunflower plant height and head diameter was investigated. The aim of research was to evaluate the effects of sunflower-legume intercropping on these traits, considering the possibility of competition between crops. The field trial was set up in April 2017 and 2018 at Institute of Field and Vegetable Crops, Novi Sad, Republic of Serbia experimental field in moderate-continental climate. Year 2017 was extremely arid with the sum of precipitation different compared to 2018. Plant height and head diameter of hybrids Rimi PR, Dukat and NS Gricko, intercropped with common vetch, red clover and alfalfa were compared with control, i.e. same sunflower hybrids grown as a sole crop. It was observed that intense growth of common vetch suppressed the growth of sunflower, and led to a decrease in measured traits in all three hybrids. Results indicated that the following combinations of sunflower and legumes are most desirable: NS Gricko/RC, Dukat/ALF, Dukat/RC and Rimi PR/ RC depending on the agro-ecological conditions. Given that the experiment was performed in years that varied significantly in agro-ecological conditions, the results indicated that red clover and alfalfa can mitigate the negative effects caused by lack of precipitation and high temperatures. In order to better understand all aspects of sunflowerlegume intercropping, further research, which should include other morphological, qualitative and quantitative indicators, is needed.

The ongoing climate change, coupled with the transformations of cultivation practices and land use in sole crop production, may cause a significant decline in sunflower yield stability. Considering that the sunflower is the third oilseed in the world oilseed market, with 45 million tons of grain per year, and that it takes the fourth position in the vegetable oil market, the implementation of sustainable growing technology in sunflower production is a necessity. Considering the above, the goal of the research was to analyze and recommend sustainable sunflower production technology in intercropping systems. A four-year trial was conducted in Serbia’s agroecological conditions (45∘34′23.2′′ N 19∘86′18.9′′ E) using a split-plot design. Two oil-type hybrids and one confectionary-type hybrid were intercropped with common vetch, red clover, and alfalfa. Common vetch × sunflower intercropping resulted in the decrease in almost all sunflower traits. Moreover, sunflower × alfalfa intercropping proved to be the most appropriate. The yield of NS Gricko and Rimi PR were statistically on the same level with sole cropping, while alfalfa biomass had better results after alfalfa was intercropped with NS Gricko, as compared to sole cropping. In view of the prevailing belief that yields are more stable in intercropping than in sole cropping, further research is needed in this respect, in addition to further research of the time and method of sowing.

The aim of this research was to determine the optimum planting density for the production of high-quality cut flowers with desirable characteristics. 25 single-stem ornamental sunflower genotypes were planted at different densities and evaluated for flowering time, flower diameter, and stem circumference and length over a two-year production cycle. Three spacing patterns were used: 25 × 25 cm, 30 × 30 cm, and 70 × 30 cm, which led to the planting densities of 160 000, 90 000, and 60 000 plants/ha, respectively. The plant density had the most important effect on the stem circumference, flower diameter, and stem length (total variation 52, 60, and 58%, AMMI analysis) and a small effect on the flowering time (total variation 1%, AMMI analysis). Based on environment-focused scaling, all high-density environments could be suitable for the production of single-stem sunflower genotypes. The results demonstrated the adaptation of several sunflower genotypes G9, G11, G12, G21, and G22 as the most suitable based on the optimum flower diameter, stem circumference, and stem length. These results may lead to progress in growing ornamental sunflowers as a cut flower.

The fast adaptation to different growing conditions of a fungus Macrophomina phaseolina, led to its becoming one of the sunflower (Helianthus annuus L.) disease causal agents in regions with a temperate climate.Methods currently used to determine sunflower resistance require laborious manual inoculation and confirmation of pathogen appearance, due to the late stage of testing. The paper proposes a cut-stem method for inoculating sunflower plants in the controlled conditions and the possibility of early-stage disease evaluation. A set of 15 sunflower inbred lines was inoculated using M. phaselolina isolate in the growth chamber and the obtained data were analysed using Cut-stem Disease Severity (CSDS) and compared with disease severity obtained from field experiments using traditional inoculation methods (toothpick, Unwounded Stem Base Inoculation (USBI) and non-inoculated plants).The results showed that, based on CSDS, inbred lines infected with the cut-stem inoculation method significantly differed regarding resistance to M. phaseolina. None of the inbred lines exhibited complete resistance but three lines could be proposed as a source of resistance to this pathogen. Ranking of inbred lines which was based on resistance to M.phaseolina was similar in all inoculation methods and in non-inoculated plants. There were highly significant correlations between the values obtained from growth chamber experiment and disease severity scores from field evaluations. Thus, the obtained results indicate that the cut-stem method could potentially complement field testing methods and be valuable tool in sunflower breeding for resistance to М. phaseolina.

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