Search

As organic agriculture represents one of the most sustainable ways of agricultural land use, the key purpose of this research was to improve confectionary sunflower production in organic agriculture. The trial compared seed yield per plant of conventional confectionary sunflower hybrids in organic vs conventional production. Subsequently, 1000 seed weight, seed yield per plant and kernel ratio of confectionary hybrids treated with the following fertilizers used in organic production: fertilizer of animal origin (G), fertilizer based on amino acids and nitrogen (T) and microbiological fertilizer (N) were compared with untreated control (C). Fertilizers enhanced yield of sunflower compared to untreated control; the highest yield was recorded in combined of G+N and G+T, all in organic agriculture system. NS Gricko had the lowest seed yield per plant compared to the other hybrids that significantly increased when treated with G+N fertilizers; same results were obtained in treatments of NS Slatki, and NS Leviathan. Preliminary results of the study indicated that application of organic fertilizers can have a positive effect on yield of sunflower in organic production conditions, which indicates that further research is necessary. Kako organska poljoprivreda predstavlja jedan od najodrživijih načina korišćenja poljoprivrednog zemljišta, svrha ovog istraživanja bila je poboljšanje proizvodnje konzumnog suncokreta u organskoj poljoprivredi. Prilikom istraživanja upoređen je prinos po biljci konvencionalnih hibrida u organskom i konvencionalnom proizvodnom sistemu. Nakon toga, upoređeni su masa 1000 semena, prinos po biljci i udeo jezgra konzumnih hibrida tretiranih sledećim đubrivima koja se koriste u organskoj proizvodnji: đubrivo životinjskog porekla (G), đubriva na bazi amino-kiselina i azota (T) i mikrobiološko đubrivo (N) sa ne tretiranom kontrolom (C). Primena ovih đubriva povećala je prinos hibrida u odnosu na kontrolu, a najveći je zabeležen u kombinaciji tretmana G+N i G+T, a sve u organskom sistemu gajenja. NS Gricko je imao najmanji, statistički značajan, prinos semena po biljci u poređenju sa drugim hibridima, koji se značajno povećan tretiranjem G + N đubrivima; isti rezultati su dobijeni kod hibrida NS Slatki i NS Leviathan. Preliminarni rezultati studije ukazuju da primena organskih đubriva može pozitivno uticati na prinos suncokreta u uslovima organske proizvodnje, što pokazuje da su dalja istraživanja neophodna.

SUMMARY Four interspecies populations, originating from three annual (H. debilis, H. praecox, H. deserticola) and one perennial (H. resinosus) wild species, were used to produce 13 new (cms) inbred lines with cytoplasmic male sterility, three Rf restorer lines with good general combining ability used as testers and their F1 hybrids. A two-year trial with three replicates was set up using the line × tester method. The inbred A-lines, Rf-testers and F1 hybrids differed significantly in the mean values for both studied traits. The mode of inheritance for leaf area was dominance and superdominance of the better parent and for plant height it was superdominance of the better parent. Highly significant positive values of general combining ability for both traits were found in inbred lines NS-G-7, NS-G-8, NS-G-9. The greatest highly significant positive specific combining ability value was found in NS-G-6 × RUS-Rf-OL-168 for the total leaf area per plant and in NS-G-6 × RHA-N-49 for plant height. The non-additive gene effect had greater influence on both traits. A significant heterotic effect was found for both traits in relation to the parental average so as in relation to the better parent.

Path coefficient analysis was used to separate direct and indirect effects of studied traits on seed oil content and seed yield, and to identify traits that could be used as selection criteria in sunflower breeding. Significant and highly significant correlations were found between most of the examined traits. Highly significant negative correlations have been established between stem diameter, total leaf area per plant, head diameter and 1,000-seed weight on one side and seed oil content on the other. Highly significant positive correlations have been established between seed yield on one side and stem diameter, total leaf area per plant, head diameter, total number of seeds per head, and the 1,000-seed weight on the other. The weight of 1,000 seeds had a highly significant direct negative effect on seed oil content and a highly significant direct positive effect on seed yield. The total number of seeds per head has demonstrated a highly significant direct positive effect on seed yield and oil content. The total leaf number per plant has demonstrated a significant direct positive effect on seed yield. A path coefficient analysis of seed yield at phenotypic level indicated that maximum direct effects were shownby the weight of 1,000 seeds, total number of seeds per head and total leaf number per plant. The total number of seeds per head was the most important trait that determined seed yield and oil content. The obtained results can be used in sunflower breeding programs aimed at the development of sunflower hybrids that combine high genetic potentials for seed yield and seed oil content.

SUMMARY Sunflower is attacked by more than 40 different diseases of which only a certain number causes serious reduction of seed yield. One of the most damaging diseases is downy mildew, which is caused by the fungus Plasmopara halstedii (Farl.) Berl. et de Toni (syn. Plasmopara helianthi Novot.). Sunflower downy mildew has great economic importance in all countries where sunflower is grown. When the meteorological conditions during the vegetation period of sunflower become favourable for disease development, the damages produce considerable reducing of the seed yield and the oil content. The best way of controlling the fungus is to grow resistant cultivars and because of that the major objective of this study was to develop sunflower genotypes genetically resistant to dominant races of downy mildew in Serbia. During this work two co-dominant CAPS markers for Pl6 gene were developed which can also be used for Pl7 gene. For introduction of these genes in breeding program marker assisted selection (MAS) was used. Developed commercial sunflower inbred lines exhibit resistance to all known races of downy mildew in Serbia indicated incorporation of resistance to downy mildew in well-known and widely produced hybrids. Besides that, Pl-genes were introduced to a large number of new inbred lines and new downy mildew resistant hybrids. These new hybrids reach higher seed and oil yields then hybrids widely produced.

One of the directions in sunflower breeding is the selection for resistance to broomrape. The population of broomrape has been stable in Serbia for a long period of time, but the racial composition has changed in recent years, with race E being predominant in the regions of north Backa and Banat. Cultivated sunflower is genetically narrow and deficient in many desirable genes. Its genetic variability can be increased by the use of wild sunflower species and interspecific hybridization. The resistance to broomrape in 15 new experimental hybrids was tested on locations in Serbia (Pacir) during three years (2006, 2007 and 2008) and in Romania (Baragan, Braila) during 2008. These hybrids were produced by crossing female inbred lines (Ha-26PR-A, PH-BC2-92-A and Ha-98-A) susceptible to broomrape race E and new Rf inbred lines (RHA-D-2, RHA-D-5, RHA-D- 6, RHA-D-7, RHA-D-8), developed from interspecific populations originating from H. deserticola and resistant to race E. All examined hybrids were resistant to broomrape in both locations. Since broomrape race F is present in the location in Romania, it is expected that the new Rf inbred lines - male components of the examined hybrids, possess the resistance gene for race F also.

SUMMARY Significant manifestation of heterosis for agronomically important traits is the main precondition for obtaining productive sunflower hybrids (Skoric et al., 2006). Development of high-yielding and stable sunflower hybrids based on interspecific hybridization requires knowledge of heterotic effects occurring in the F1 generation. Heterosis for seed yield per plant, total seed number per head and 1,000-seed weight was studied in interspecific hybrids obtained by the line × tester method. The seven female inbred lines used in the study had been developed by interspecific hybridization, while the three male restorer inbreds with good combining abilities were used as testers in the form of fertility restorers. Twenty-one F1 hybrids were obtained by crossing each tester with each female inbred line. A trial with the lines and F1 hybrids was set up at Rimski Sancevi. Experiment Field of Institute of Field and Vegetable Crops in Novi Sad using a randomized block design with three replications. Our study found significant differences in the mean values of all the traits under investigation. Heterosis values for seed yield were positive and highly significant relative to parental average (98.4-274.1%) as well as better parent (55.8-223.2%). Considerably less heterosis was found for total seed number per head (69.6-203.7%) relative to parental average and better parent (47.6-183.3%). With 1,000-seed mass, the values ranged between 26.5% and 48.8% relative to parental average and from -42.4% to 30.9% relative to better parent. This study could prove useful in the development of new high-yielding sunflower hybrids based on interspecific hybridization.