The abundance and diversity of species within the genus Helianthus offer numerous and rewarding possibilities to sunflower breeders. All annual species and a large number of perennial species may be crossed to the cultivated sunflower by the conventional hybridization method. On the other side, the divergence and heterogeneity of the genus cause considerable difficulties, such as cross-incompatibility, embryo abortiveness, sterility and reduced fertility in interspecific hybrids. Because of that, methods of somatic hybridization, “in vitro” embryo culture, chromosome doubling, etc. are frequently used for interspecific crossing. Cytogenetic studies are used for determinations of chromosome number and structure and analyses of meiosis (microsporogenesis) and pollen viability, making it possible to establish phylogenetic relations between wild sunflower species and the cultivated sunflower and enabling the use of the former in sunflower breeding. Cytogenetic studies of the sunflower have evolved from cytology, through cytotaxonomy and classic cytogenetic to cytogenetic-molecular studies. Most intensive progress of cytogenetic studies has been associated with the use of interspecific hybridization in sunflower breeding.

RS1 and RS2 are two genetic stocks that have low saturated fatty acid (SFA) contents. In this two-year study, we report on the inheritance of palmitic and stearic acids of RS1 and RS2 in the F1 and F2 generations of crosses with HA 382, an inbred line with a fatty acid composition similar to many commercial sunflower hybrids. The expression of the reduced palmitic and stearic acid traits is most important in the F2 generation because it is the F2 seed that is harvested by the farmer, sold, and crushed for the oil. Our experiments showed that the F2 seed of reciprocal crosses of RS1 or RS2 with HA 382 was intermediate in SFA content between the two hybrid parents. The inheritance and expression of the reduced palmitic and stearic acid traits of RS1 and RS2 were controlled by more than one gene. In addition, there were significant relative changes in palmitic and stearic acid contents between the growing seasons of 2002 and 2003, suggesting that environment played a significant role in the relative proportions of these fatty acids. The total SFA content was also influ enced by environment, producing opposite effects with RS1 (higher total SFA in 2003) and RS2 (lower total SFA in 2003). The data demonstrate that it will be necessary to incorporate the reduced SFA trait into both parents of a hybrid in order to achieve the lowest concentration of SFAs in the F2 seed.

Genetic variability for resistance to Alternaria leaf spot disease (Alternaria helianthi) can be induced by radiation or chemical mutagens. The objec tives of this study were to create genetic variability in cultivated sunflower and to select lines resistant to Alternaria leaf spot. In the first experiment, sunflower seeds of the genotype HA BR 104 were irradiated with 150 and 165 Gy of gamma rays. Seeds were sown in the field at the Embrapa Soybean experimental station, in Londrina, PR, Brazil and M1 plants were harvested in bulk. M2 ,M3 and M4 plants were screened for disease resistance under natural infection in the field. Plants were evaluated for Alternaria leaf spot symptoms, using a diagrammatic scale from 0 (no symptoms) to 5 (maximum infection). Before flowering, plants showing no symptoms of Alternaria leaf spot (grade 0) or less than 5% diseased leaf area (grade 1) were bagged for self-pollination. Self-pollinated plants and open-pollinated plants from 150 Gy and 165 Gy populations with no or mild disease symptoms were selected. In the second experiment, sunflower seeds of the genotypes HA 300 and HA BR 104 were treated with ethyl methanesulfonate (EMS) at 0.015 mol dm-3. Selected M2 and M3 were screened for disease resistance in the field. From the EMS treatment, 300 M3 plants with no disease were recovered. All these lines will be tested for combining ability. The best lines will be used for hybrid production.

An investigation was carried out at the experimental plots of the Department of Genetics and Plant Breeding, Main Research Station, University of Agricultural Sciences, Hebbal, Bangalore, India to predict the level of heterosis based on genetic divergence through regression analysis in sunflower. One hundred and forty crosses involving 10 lines and 14 testers were affected and evaluated for ten quantitative traits. Better parent heterosis (BPH) of crosses was estimated and correlated with genetic divergence between parents as measured by Mahalanobi’s D2 statistic. The relationship between character wise parental divergence and better parent heterosis only for five important characters viz., plant height, head diameter, seed yield, oil content and oil yield, was determined using linear regression and curvilinear regression of second degree. The estimates of better parent heterosis significantly regressed towards the genetic distance of the parents. However, it was not enough for successful prediction of heterosis through either linear or curvilinear regression of second degree as indicated from highly significant chi-square values for observed and predicted estimates of heterosis for all these characters.

An investigation was carried out at the experiment plots of the Department of Genetics and Plant Breeding, Main Research Station, University of Agricultural Sciences, Hebbal, Bangalore, India, to assess the stability of fifteen newly developed sunflower hybrids along with four checks across four seasons using a non parametric stability model for simultaneous selection of high yielding and stable hybrids. Highly significant mean squares due to genotype × environment interaction suggested differential performance of hybrids across the four seasons for all the characters except plant height, stem diameter, head diameter and test weight. Hybrid 9 was found to be highly stable for five characters, viz., plant height, volume weight, oil content, oil yield and earliness. Apart from this hybrid, hybrids 4 and 11 were stable for three characters, viz., head diameter, seed yield and oil yield. Another hybrid, number 5, was also stable for seed and oil yields.

A comparative study was carried out on the parthenogenetic reaction of Helianthus annuus L. lines and hybrids used as initial female material for parthenogenetic induction. It was established that the mean parthenogenetic responsiveness of the hybrids was considerably higher than that of the lines. The mean parthenogenetic responsiveness of the lines used as initial female material (2607 A, 2607 B, 1607 A, 1607 B, 1234 A and 1234 B) was lower than the mean responsiveness of the hybrids (Albena, Viki, Euroflor, Perla and San Luka). Within the investigated lines, no specific genotype reaction with regard to parthenogenetic induction was ascertained; such reaction was observed in the hybrids. The hybrids San Luka and Perla had the relatively highest parthenogenetic responsiveness. The analysis of the results showed that the optimal expression of the par thenogenetic responsiveness of the female genotype depended mainly on the interaction with the pollen source. The pollen source Rf 673 induced on average 3.4 times better parthenogenetic reaction in the hybrids Perla, San Luka and Viki that the line Rf 147. The γ-irradiation influenced the expression of parthenogenetic responsiveness of the female genotype through its effect on the parthenogenesis inducing ability of the pollen source.

The experiments comprising 25 sunflower hybrids were conducted in three locations in 2000 and 2001. These hybrids were evaluated for combining ability of 6 important yield components. Based on observations in this research, the average flowering duration of the hybrids ranged from 69.6 to 71.8 days, physiological maturity from 98.7 to 104.2 days, hectoliter weight from 355.2 to 408.5 g, 1000-seed weight from 32.5 to 43.5 g, plant height from 98.3 to 134.3 cm and head diameter from 12.6 to 14.0 cm. Based on all combining ability analyses performed in this research, the cross 2453-A × R-1001 was determined as the best hybrid in the experiment. Among the parental lines, HA89-A and 2644-R were chosen as first female and male testers, respectively; BAH8-A and 2280-R were chosen as second testers for testing combining ability of lines for use in future breeding programs in sunflower.

Estimated gains from selection and interrelationship among agronomic characters were evaluated in the random-mating sunflower populations Local Open and UAF using data from two seasons (spring and fall). Among 66 combinations of 12 traits included; number of leaves per plant with days to anthesis and head diameter; plant height with seed yield per plant; days to flowering with days to anthesis, days to maturity and head diameter; days to anthesis with days to maturity, head diameter and seed yield per plant; and days to maturity with seed yield per plant showed significant, positive correlations in both sunflower populations during spring. Most often, genetic correlations were slightly higher than their respective phenotypic correlations in UAF sunflower population during spring and fall. But the trend was almost reverse in Local Open during both seasons. Estimates of percentage gain per generation for selection at 20% intensity indicated that this selection would be effective for improving seed and oil yield. The estimated gain for achene yield was 31.33 and 24.38% per generation (Local Open and UAF) when S1 testing was conducted in spring season. Correlated responses to S1 selection for yield and the components of yield indicated that indirect selection for achene yield and oil yield would be effective. Direct selection for yield was estimated to result in favorable increases in all yield components.

Genetic variability of two random-mating sunflower (Helianthus annuus L.) populations, Local Open and UAF, was evaluated in two seasons (spring and fall). One hundred S1 families selected randomly each population were included in the experiment conducted at Faisalabad (Pakistan). Genotype × environment variances for all traits, especially seed yield, oil yield and the number of achenes per head, were larger in Local Open than in UAF.

Principal component analysis has been explored for assessing the consistency of 14 plant traits for sunflower growth using multivariate data of 6 field experiments conducted during kharif 1994 to 1999 seasons on rainfed alfisol. Seven genotypes have been used in the study viz., Guj-sun-1, MSFH-8, MSFH 17, KBSH-1, Jwala, Pac-36 and Morden. Observations were recorded on leaf nitrogen, leaf area, leaf weight, leaf number, stem nitrogen, stem weight, root length, root weight, stomatal conductance, photosynthesis, total biomass on 30, 45 and 60 days after sowing (DAS) and flower head diameter and flower head weight on 45 and 60 days after sowing in each season. The first two principal components have extracted about 80% of variance in the data of different plant traits on different days after sowing. The consistency of plant traits has been assessed by examining correlations between different plant traits and the distribution of loadings of plant traits on the first two leading principal components 30, 45 and 60 days after sowing. The results have indicated that stem weight and lead number on the 30th day, leaf area and leaf weight on the 45th day and leaf area, leaf weight and total biomass on the 60th day after sowing had significantly higher loadings on the 1st principal component. Similarly, root length on the 30th day, flower head diameter and flower head weight on the 45th day and root length and photosynthesis on the 60th day after sowing had significantly higher loadings on the 2nd principal component. Based on a graphic plot of the loadings, root length (30 and 60 DAS), stomatal conductance (30, 45 and 60 DAS) and photosynthesis (30 DAS) were found to be consistent since their loadings on the 1st principal component had high mean values with low standard deviations. Similarly, stem nitrogen (45 and 60 DAS), stomatal conductance (45 DAS), photosynthe sis (30 DAS), leaf nitrogen (60 DAS), root length (30 DAS), flower head diameter (45 DAS) and flower head weight (45 DAS) were also consistent since their loadings on the 2nd principal component had high mean values with low standard deviations.

The present investigation, aimed at sunflower population improvement through cyclic selection, was initiated at Directorate of Oilseeds Research (DOR), Hyderabad, India. The base population (C3), which consisted of 20,000 plants for the third cycle, was raised during summer 2001 and 2,000 phenotypically superior plants were selfed. Based on self-fertility, best 200 plants were selected for progeny test during kharif 2001 and evaluated against two checks (Morden and KBSH-1). In the C3 base population, wide range of variability was exhibited for plant height, days to maturity, head diameter, number of filled seeds, seed yield, number of unfilled seeds and oil content. Positive selection differential was observed for plant height, head diameter, seed yield and oil yield, whereas days to maturity and oil content showed negative values. PCV and GCV revealed high values for seed yield, oil yield and moderate values for plant height, head diameter, 100-seed weight and oil content. Heritability values were high for seed yield, 100-seed weight, days to 50% flowering, days to maturity, plant height, head diameter and oil yield. High heritability coupled with high genetic advance was observed for head diameter and oil yield. The elite genotypes with high seed yield, number of filled seeds and oil content were selected for intermating to generate next base population for cyclic selection. Superior genotypes may serve to develop inbreds for use in heterosis breeding.

Development of new, more aggressive isolates of Phomopsis helianthi in Serbia and Montenegro has been investigated. Two isolates of Phomopsis helianthi, Yu 4 and Yu 12, had been found on the stem of NS-H-45, a highly tolerant sunflower hybrid. The isolate Yu 4 was isolated in the northern part of the Vojvodina Province, a region where Phomopsis typically occurs. The isolate Yu 12 comes from the southern part of the Vojvodina Province, a region along the Danube River, which suffered an intensive outbreak of Phomopsis in 1997. A preliminary study of the isolates showed that these two isolates were signifi cantly different for radial growth in Petri dish. A test was thus made with recombinant inbred lines in the F9 generation developed from the cross of LR 4-17 (inbred line with high tolerance to Phomopsis) and HA-89 (susceptible inbred line). Experiments were conducted in the greenhouse, inoculating plant leaf tips with the mycelium of the fungus. The test showed that there were no significant differences between the two isolates, Yu 4 and Yu 12. It was concluded that the intensive attack recorded in 1997 along the Danube River occurred due to exceptionally favorable environmental conditions for the development of the disease.

Sclerotinia head rot, caused by Sclerotinia sclerotiorum (Lib.) de Bary, is a major disease in sunflower (Helianthus annuus L.). Development of hybrids with adequate genetic resistance is necessary to reduce yield losses. The objective of this study was to find an effective technique of inoculating sunflower heads with Sclerotinia sclerotiorum for screening and identifying resistant and susceptible genotypes. A factorial experiment was conducted to evaluate the effectiveness of different inoculation procedures. The factors were bag color, water treatment, inoculum type, and rate of inoculation. Based on the results of this study, the inoculation procedure recommended to sunflower researchers who wish to screen lines or hybrids for Sclerotinia head rot resistance is spraying the heads at the beginning of flowering with 5 cm3 of a suspension of ascospores containing 5000 ascospores per milliliter and covering the heads with brown paper bags immediately after inoculation. Application of additional water is not needed. Measurements of infection could begin as early as 35 days after inoculation

Mineral nutrition is a factor affecting in vitro regeneration. Various requirements for individual mineral elements between plant species and also between genotypes of the same species have led to the differentiation and definition of the significance of the genetic background in determining callus biochemical characteristics and a confirmation whether different requirements for nutrients leave a possibility of achieving better and more efficient regeneration with a specific modification of substratum composition. The practical aspect of the obtained results lays in the fact that the sunflower species are characterized by low regeneration ability. It was shown that the dynamics of uptake and accumulation of mineral elements into callus cells is a genotype dependent trait being more or less evident depending upon element. Total nitrogen content was between 4 and 5%. The sunflower genotype PH-BC2-101A showed the highest accumulation of nitrogen, phosphorus and, to some extent, calcium. Consequently, a high accumulation of total dry matter without pigment synthesis was recorded. A high nitrogen accumulation in the cited genotype resulting in the highest nitrate reductase activity a very high accumulation of soluble proteins (enzymes).

Successful interspecific hybridization was carried out between the wild perennial diploid species Helianthus pumilus Nutt., accession GT-M-172, and cultivated H.annuus L. The cross compatibility between H.pumilus and H.annuus was much higher when the wild species was used as the male in the crosses. Insemination (seed set) was very low in both directions. In order to prove the presence of considerable variability in the early F1 generation, some statistical methods were used for evaluation of morphological traits such as plant height, head diameter, number of disk flowers and insemination. Heterosis was detected for plant height. Cases of partial to complete dominance of the cultivated parent prevailed. A high level of segregation was observed in the F2 generation, therefore, traits depression and transgression were evaluated for plant height, head diameter, number of florets and seed set. A triple pheno typic correlation appeared between three characters in sunflower and one of them was confirmed on genetic level as well. Resistance to Plasmopara helianthi, Orobanche cumana and Phomopsis helianthi was discovered in different progenies of the interspecific hybrids of H.pumilus.

Immature zygotic embryos from the Bulgarian fertility restorer line R 147 (male component of the commercial hybrid Albena) were used as donor material for induction of direct organogenesis in sunflower (Helianthus annuus L.). Range of spontaneous somaclonal variation among the progenies of regener ants has been assessed. Genetic modifications observed in the regenerants included agronomic traits such as oil content in seed, 1000-seed weight, plant height, petiole length, internode length, number of branches, length of branches, number of ray florets, seed width and seed length. The somaclonal line R 12001 showed a modified architecture and higher oil content in seed than the standard R 147, and very good combining ability. The hybrid Julia, an offspring of the somaclonal line R 12001, showed seed and oil yields higher by 18.3% and 17.0%, respectively, than those in the standards Albena and Super Start. In the 2002 tests of the State Variety Testing Commission, the hybrid Julia had a higher seed yield than the standards` mean. Such combination of these favorable changes is desirable in breeding work on sunflower. Somaclonal variation through direct organogenesis facilitated the creation of genetically heritable variation in sunflower, which can be used with for effective production of highly productive and adaptable hybrids.

Damage caused by the cotton bollworm (Helicoverpa armygera HÜBNER) was first observed in the southern part of Bács-Kiskun County in 1994. This observation was made in Bácsalmás, in a sunflower field of 150 ha was used for hybrid seed multiplication. Several insecticide applications were necessary to effectively control the pest. In 1995, this type of protection had to be applied in a field of 1200 ha in Bácsalmás. In the southern part of Hungary, this insect is present in high numbers every year. Protection of sunflower seed fields would not be possible without the integrated protection technologies developed against this insect. En masse occurrence of the species was examined in the regions of Kecskemét and Bácsalmás towns, in commercial sunflower fields. According to our large-scale investigation, 322 sunflower heads of the 500 examined (64.4%) were found to be infected on 3 August 2003. The level of infection was as high as 418 heads (83.6%) in the Bácsalmás region. Concerning the number of larvae found per single head, the situation was similar. The average numbers of larvae found per single sunflower head were 5.22 and 8.09 in the regions of Kecskemét and Bácsalmás, respectively. Simultaneously, Rhizopus spp. fungi infections were found in 22.2% and 27.8% of the sunflower heads in Kecskemét and in Bácsalmás, respectively. Parasitoid ichneumons (ectoparasites) were observed in 9 and 7.4% of the larvae. The extent of damage due to cannibalism was 1-2% of larvae. This rate was not considered as significant. The study provides important technical information for the integrated protection against this insect species, which causes significant damage.

Western European and especially German-based multinational food processing companies tend to grow confectionery sunflower hybrids and varieties in Hungary. This commercial product is highly preferred as substitute for walnuts, as filling in chocolate, bread and other bakery products, or as seasoning. In the early 1990s, German companies rejected several truckloads of confectionery sunflower due to “greening of the kernel in the achene”. Almost 90% of the rejected consignments originated from a sandy terrace in the region between the rivers Danube and Tisza, which at the time was severely infected with the Asclepias syriaca L. Field investigations revealed unambiguously that the greening of the kernel in the achene had been caused by the red spotted bug (Spilostethus [=Lygaeus] equestris L.). This species is able to cause extensive damage and discontinuity in the so-called shoulder part of the achene with its powerful stinging-suctorial mouth organ. Intensive chlorophyll synthesis begins in the damaged area due to the solar effect, which is undoubtedly the cause for the greening of the kernel in the achene. In this investigation, we studied confectionery sunflower fields in two neighboring areas (Bácsalmás and Katymár) for extent of damage caused by Spilostethus [=Lygaeus] equestris L. While in Bácsalmás (that district less infected with the Asclepias syriaca L.) we found a damage of decreasing inten sity (8.85 damaged achenes per sunflower disc) as advancing towards the centre of the field, this value was almost three times as high, reaching 31.71 of damaged achenes per disc, in the area of Katymár (the area severely infested with Asclepias syriaca L.). Though the numbers are not very high in them selves - assuming that a well-developed disc contains 1100 to 1200 seeds - the damage may result in significant reduction of kernel quality. Our extensive research into the causes of the greening of the sunflower kernels made it clear that Spilostethus [=Lygaeus] equestris L. had a significant influence on the chemical composition of the damaged achenes: it increased the proportion of linoleic acid (C-18:2) by about 2.5%. That affects the lasting quality of the achene unfavorably (Horváth and Bujáki, 1991). For this reason, a comprehensive study of the biology of Spilostethus [=Lygaeus] equestris L. was undertaken in order to develop effective protection methods. This study was a pioneer investigation of exogenous and endogenous factors that might obstruct the use of confectionery sunflower hybrids and varieties in food industry.