Zvonimir Sakač

Effect of excess lead on sunflower growth and photosynthesis

Abstract The effect of different lead (Pb) concentrations in the nutrient solution on the growth, Pb and chlorophyll a+b content, chlorophyll fluorescence and quenching parameters in the leaves of young sunflower (Helianthus annuas L.) plants was studied. The content of Pb in the analyzed plant parts increased following the increase in Pb content in the nutrient medium. This increase was expressed to a higher extent in the roots than in the stems and leaves. In the presence of high concentration of Pb in the leaf area, the dry mass and the height of plants were reduced. Lead treatment of sunflower plants led to a pronounced reduction of chlorophyll (a+b) content, accompanied by much smaller decrease of photosynthetic O evaluation rate and PSll efficiency at low light intensity. Hence, Pb effect2did not result in the destruction of the photosynthetic apparatus, but in its reduction. The highest Pb concentration in the nutrient solution induced, however, at saturating photon flux density (PFD) a decrease in...

Photosynthesis, chlorophyll fluorescence and soluble carbohydrates in sunflower leaves as affected by boron deficiency

Abstract The effect of various boron levels in the nutrient solution on the growth, boron and chlorophyll content, photosynthesis and chlorophyll fluorescence in the leaves of young sunflower (Helianthus annuus L.) plants was studied under greenhouse conditions. Deficiency of boron decreased the dry matter yield of the roots, shoots and leaves. The content of boron in all analyzed plant parts increased with the increase of boron levels in the nutrient solution, more so in the shoots than in the roots. Leaf area was reduced under boron deficiency as well as the content of chlorophyll in the leaves. The content of analyzed sugars was increased in boron deficient plants, glucose content exhibited the highest increase under boron deficiency. Boron deficiency appreciably decreased photosynthetic oxygen evolution by leaves, the apparent quantum yield and quantum efficiency of photosystem two electron transport. The diminished rate of photosynthesis in boron deficient sunflower leaves could be correlated to the ...

Genetic possibilities for altering sunflower oil quality to obtain novel oils

The sunflower is one of the four most important oilseed crops in the world, and the nutritional quality of its edible oil ranks among the best vegetable oils in cultivation. Typically up to 90% of the fatty acids in conventional sunflower oil are unsaturated, namely oleic (C 18:1, 16%-19%) and linoleic (C 18:2, 68%-72%) fatty acids. Palmitic (C 16:0, 6%), stearic (C 18:0, 5%), and minor amounts of myristic (C 14:0), myristoleic (C 14:1), palmitoleic (C 16:1), arachidic (C 20:0), behenic (C 22:0), and other fatty acids account for the remaining 10%. Advances in modern genetics, most importantly induced mutations, have altered the fatty acid composition of sunflower oil to a significant extent. Treating sunflower seeds with gamma- and X-rays has produced mutants with 25%-30% palmitic acid. Sunflower seed treatment with X-rays has also resulted in mutants having 30% palmitoleic acid, while treatments with mutagenic sodium azide have produced seeds containing 35% stearic acid. The most important mutations have been obtained by treatment with dimethyl sulfate, which produced genotypes with more than 90% oleic acid. Mutants have also been obtained that have a high linoleic acid content (>80%) by treating seeds with X-rays and ethyl methanesulfonate. Of the vitamin E family of compounds, sunflower oil is known to predominantly contain alpha-tocopherol (>90%). Spontaneous mutations controlled by recessive genes have been discovered that significantly alter tocopherol forms and levels. The genes in question are tph(1) (50% alpha- and 50% beta-tocopherol), tph(2) (0%-5% alpha- and 95%-100% gamma-tocopherol), and tph(1)tph(2) (8%-40% alpha-, 0%-25% beta-, 25%-84% gamma-, and 8%-50% delta-tocopherol). The existence of (mutant) genes for increased levels of individual fatty acids and for different forms and levels of tocopherol enables the development of sunflower hybrids with different oil quality. The greatest progress has been made in developing high-oleic hybrids (>90% oleic acid). There has been considerable work done recently on the development of high-oleic hybrids with altered tocopherol levels, the oil of which will have 10-20 times greater oxidative stability than that of conventional sunflower oil. While sunflower breeders work on developing hybrids with altered oil quality, medical scientists in general and nutritionists in particular will determine the parameters for the use of these novel types of oil that can improve human nutrition and be used in the prevention of cardiovascular diseases.

Photosynthesis, chlorophyll fluorescence, and water relations in young sugar beet plants as affected by sulfur supply

Abstract The effect of different concentrations of sulfur (1 and 3 mM) and interruption of sulfur (S) supply for 25 days on the photosynthesis and leaf water relations in young sugar beet plants (Beta vulgaris L.) was studied in water culture, under greenhouse conditions. Interruption of S‐supply significantly reduced the content of sulfur, chlorophylls a+b and carotenoids, leaf area, density of stomatal and epidermal cells, transpiration rate and leaf water potential, while it increased the free proline content and stomatal diffusion resistance. An increase in S concentration in the nutrient medium from 1 to 3 mM did not significantly affect the tested parameters, except for an increase in leaf S content and a decrease of leaf water potential. Sulfur deficiency caused a pronounced decrease of the rate and quantum yield of photosynthetic oxygen evolution under non‐photorespiratory conditions. This was partly the result of the diminished photochemical efficiency of photosystem II reaction centers. Less efficient excitation of PSII reaction centers is most probably the consequence of higher thermal energy dissipation in the reaction centers of S‐starved plants. These data support that S nutrition is one of the factors regulating plant photosynthesis.

Development of sunflower hybrids with different oil quality

SUMMARY The cultivated sunflower (Helianthus annuus L.) is one of most important oil crops of the world. Although sunflower is primarily grown for extraction of its seed oil there is a limited production of non-oilseed sunflower types which are used in confections industry or as bird feed. The objective of this research was development of hybrids with high and stable oleic acid content and modified tocopherol composition, with high values for the two most important agronomic characters (seed yield and oil yield) and high tolerance to Phomopsis. The incorporation of the gene Ol+tph1 into these genotypes has led to the development of high-oleic hybrids with altered tocopherol profiles. Oil of these hybrids has a much longer shelf-life than standard sunflower oil. The process of incorporating the genes Ol+tph2 and Ol+tph1tph2 into highly productive sunflower genotypes is under way. The most important results of this line of research are the newly developed female lines with the oleic acid content in oil over 90% and the male lines (restorers) with an oleic acid content in the 89-93% range. Using these lines, hybrids will be developed whose oleic acid content in oil will exceed 90%. RESUMEN El girasol cultivado (Helianthus annuus L.) es uno de los cultivos oleaginosos más importantes del mundo. Aunque el girasol se cultiva antes de todo para la producción de aceite, los tipos de girasol no oleaginosos, se cultivan en menor rango para la industria confitera y alimentos para pájaros. El objetivo de esta investigación fue creación del híbrido con el contenido alto y estable de ácido oleico y contenido modificado de tocoferol, altos valores de dos características agronómicas más importantes (rendimiento de semilla y rendimiento de aceite) y alta tolerancia hacia Phomopsis. La introducción de los genes Ol+tph1en esos genotipos, llevó hasta la creación de los híbridos altamente oleicos con diferentes contenidos de tocoferol. El aceite de esos híbridos se conserva mucho más tiempo que el aceite estándar de girasol. El proceso de introducción de los genes Ol+tph2y Ol+tph1tph2en los genotipos de girasol altamente productivos, está en curso. Los resultados más importantes de estas investigaciones son líneas maternas nuevas creadas con el contenido del ácido oleico por encima de 90% y líneas paternas (restauradores) con el contenido del ácido oleico en el rango entre 89 y 93%. Utilizando estas líneas, pueden crearse híbridos con el contenido del ácido oleico en el aceite, por encima de 90%. RÉSUMÉ Le tournesol de culture (Helianthus annuus L.) est l’une des cultures oléagineuses les plus importantes du monde. Bien que le tournesol soit cultivé tout d’abord pour la production d’huile, des types de tournesol non oléagineux sont cultivés en plus petite quantité pour l’industrie de la confiserie et pour la nourriture des oiseaux. Le but de cette recherche était de créer un hybride ayant un contenu élevé et stable d’acide oléique et une composition modifiée du contenu de tocophérols, avec des valeurs importantes pour les deux caractéristiques agronomiques les plus importantes (rendement en graines et rendement en huile et avec une grande tolérance au Phomopsis. L’incorporation du gène Ol+tph1 dans ces génotypes a mené au développement d’hybrides à haute teneur oléique avec différents contenus de tocophérols. L’huile de ces hybrides se conserve beaucoup plus longtemps que les huiles de tournesol standard. Le procédé d’incorporation de gènes Ol+tph2 et de Ol+thp1tph2 dans les génotypes de tournesol très productifs est en cours. Les résultats les plus importants de cette recherche sont les lignées femelles nouvellement créées ayant un contenu d’acide oléique dans l’huile de plus de 90% et les lignées mâles de restauration ayant un contenu d’acide oléique sur une portée de 89 et 93%. L’utilisation de ces lignées peut permettre la création d’hybrides ayant un contenu d’acide oléique dans l’huile de plus de 90%.

HETEROSIS FOR AGRONOMICALLY IMPORTANT TRAITS IN SUNFLOWER (Helianthus annuus L.)

SUMMARY Significant manifestation of heterosis for agronomically important traits is the main precondition for obtaining productive sunflower hybrids (Škorić etal., 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 Šančevi. 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. RESUMEN La presentación del heterosis significante para las características importantes desde el punto de vista agronómico, es la condición principal para la obtención de híbridos de girasol productivos (Škorić y colaboradores, 2006). La creación de híbridos de girasol estables y de alto rendimiento sobre la base de hibridación de interespecies, requiere el conocimiento de los efectos heteróticos que se presentan en la generación F1. El heterosis para el rendimiento de semilla por planta, el número total de semillas por capítulo y el peso de 1000 granos, ha sido investigadazo en los híbridos interespecies obtenidos por el método línea × testador. Siete líneas consanguíneas (inbred) de la madre, utilizadas en esta investigación, fueron creadas por la hibridación de interespecies, mientras que tres líneas masculinas restauradoras, con buena habilidad de combinación, fueron utilizadas como testadores en forma de restauradores de fertilidad masculina. Cruzando cada testador con cada línea materna, fue obtenido el híbrido 21 F1. La investigación de las líneas y el híbrido F1, fue realizada en tres repeticiones en el campo experimental del Instituto de Agricultura y Horticultura de Novi Sad, en Rimski Šanèevi. En la investigación fueron determinadas diferencias significantes en los valores medios de todas las características investigadas. Los valores heteróticos para el rendimiento de la semilla fueron positivos y altamente significantes en relación con el promedio de los progenitores (98,4-274,1%) tanto como del mejor progenitor (55,8- 223,2%). Significativamente menor heterosis fue encontrado para el número total de semillas por capítulo (69,6-203,7%) en relación con el promedio de los progenitores y del mejor progenitor (47,6-183,3%). En cuanto al peso de 1000 granos, los valores oscilaban entre 26,5% y 48,8% en relación con el promedio de progenitores y desde -42,4% hasta 30.9% en relación con el mejor progenitor. Esta investigación podría demostrarse útil en creación de de híbridos de girasol de alto rendimiento, sobre la base de hibridación de interespecies. RÉSUMÉ La manifestation d’une hétérosis importante est la condition principale pour les caractéristiques agronomiques d’hybrides de tournesols productifs (Škorić et al., 2006). Le développement d’hybrides de tournesol stables et à grand rendement basés sur l’hybridation interspécifique exige la connaissance des effets d’hétérosis apparaissant dans la génération F1. L’hétérosis pour le rendement de graines par plante, le nombre total de graines par tête et le poids de 1,000 graines a été étudié dans les hybrides interspécifiques obtenus par la méthode lignée × testeur. Sept souches pures mères utilisées dans cette recherche ont été développées par hybridation interspécifique tandis que trois souches de restauration mâles ayant de bonnes aptitudes de combinaison ont été utilisées comme testeurs sous forme de restaurateurs de fertilité mâe. Vingt-un hybrides F1 ont été obtenus par croisement de chaque testeur avec chaque source pure femelle. Un essai avec les lignées et les hybrides F1 a été fait en trois fois dans le champ expérimental de l’Institut d’Agriculture et d’Horticulture de Novi Sad. L’étude a constaté des différences importantes dans les valeurs moyennes de toutes les caractéristiques étudiées. Les valeurs d’hétérosis pour le rendement en graines étaient positives et très significatives par rapport à la moyenne parentale (98,4-274,1%) aussi bien que par rapport à celle du meilleur parent (47,6-183,3%). Pour le nombre total de graines par tête une hérétosis beaucoup moindre a été constatée par rapport à la moyenne du parent (69,6-203,7%) et du meilleur parent (47,6-183,3%). Pour ce qui est du poids de 1000 graines, les valeurs variaient de 26,5% et 48,8% relativement à la moyenne du parent et de -42,4% à 30,9% par rapport au meilleur parent. Cette étude pourrait se montrer utile lors de la création d’hybrides de tournesol à grand rendement basés sur l’hybridation interspécifique.

Genotype by environment interactions for seed yield and oil content in sunflower (H. annuus L.) using AMMI model.

SUMMARY Stability of 25 new sunflower hybrid combinations was compared against three standard hybrids in three locations. Seed yield per unit area and oil content in seed were measured using AMMI analysis. The tested combinations showed significant variations in seed yield (t ha-1) and oil content in seed (%) from one location to another and within individual locations. Variations in seed yield were mostly due to the impact of location, while the variations in oil content were prevalently due to genotypic differences among the hybrids. The highest and lowest average total yields were obtained by the hybrids G20 and G1, respectively. The hybrids G17, G8, G2 and G21 showed the widest adaptability. Slightly narrower adaptability was exhibited by the hybrids G4, G7, G13, G14, etc. The hybrids G6, G16, G15 and G22 showed the narrowest adaptability, i.e., they were considerably affected by the analyzed interactions. The highest and lowest average oil contents were recorded in the hybrids G23 and G28, respectively. The hybrids G7, G11 and G23 demonstrated the highest adaptability for oil content in seed. The lowest adaptability was demonstrated by the hybrids G1 and G16.

Assessment of quality of new Rf inbred lines resistant to broomrape rase E (Orobanche cumana Wallr.) developed from H. deserticola by interspecific hybridization.

SUMMARY Broomrape (Orobanche cumana Wallr.) presents a serious problem in sunflower production in a number of countries. 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 Bačka and Banat. Cultivated sunflower is genetically narrow and deficient in many desirable genes. Sources of resistance genes to broomrape can be found in a number of wild sunflower species. New 7 Rf inbred lines (RHA-D- 1, RHA-D-2, RHA-D-5, RHA-D-6, RHA-D-7, RHA-D-8, RHA-D-9) were produced from interspecies population originating from H. deserticola (DES-1474-1) in IFVC. The inbreeding of the selected plants from interspecific populations started in 1995 (S1). The first screening of sunflower Rf lines for broomrape resistance was done in a glasshouse in 1999 (S5). The seed from the resistant plants was tested in infested fields, in the area of S. Miletić and B. Topola during 2000 (S6). Selection of resistant plants was checked from 2001 (S7) to 2003 (S9). The same procedure was conducted in Pačir from 2004 (S10) to 2008 (S14) and in the area of Lipar in 2009 (S15). Experimental hybrids were produced by crossing new Rf lines developed from interspecific population (DES-1474-1) resistant to broomrape race E with cms female lines susceptible to broomrape. The resistance of new 28 experimental hybrids to broomrape was checked on locations in Serbia (Pačir 2006, 2007, 2008) and at the location (Lipar 2009) with three controls: hybrid Bačvanin, resistant to race E, hybrid NS-H-111 resistant to race A, B, C, D, susceptible to E race and line AD- 66 susceptible to all broomrape races. The resistance of the same hybrids was also tested at a location in Romania (Baragan, Braila) in 2008. All examined hybrids were resistant to broomrape race E on all locations.