Perennial Helianthus Research Articles

Transcriptome resources for the perennial sunflower Helianthus maximiliani obtained from ecologically divergent populations

Next-generation sequencing (NGS) technologies provide a rapid means to generate genomic resources for species exhibiting interesting ecological and evolutionary variation but for which such resources are scant or nonexistent. In the current report, we utilize 454 pyrosequencing to obtain transcriptome information for multiple individuals and tissue types from geographically disparate and ecologically differentiated populations of the perennial sunflower species Helianthus maximiliani. A total of 850 275 raw reads were obtained averaging 355 bp in length. Reads were assembled, postprocessing, into 16 681 unique contigs with an N50 of 898 bp and a total length of 13.6 Mb. A majority (67%) of these contigs were annotated based on comparison with the Arabidopsis thaliana genome (TAIR10). Contigs were identified that exhibit high similarity to genes associated with natural variation in flowering time and freezing tolerance in other plant species and will facilitate future studies aimed at elucidating the molecular basis of clinal life history variation and adaptive differentiation in H. maximiliani. Large numbers of gene-associated simple sequence repeats (SSRs) and single-nucleotide polymorphisms (SNPs) also were identified that can be deployed in mapping and population genomic analyses.

Potential Use of Perennial Sunflower to Reduce Blackbird Damage to Sunflower

Wildlife Conservation Sunflower Plots (WCSP) have shown potential to reduce blackbird (Icteridae) damage in commercial sunflower. Also known as lure, decoy, or trap crops, WCSP are strategically placed food plots that provide an easily available and proximate food source that entices blackbirds away from valuable commercial crops. By providing an alternative food source, WCSP reduce direct damage to commercial fields, while also lowering indirect costs that producers incur attempting to prevent blackbird damage. However, cost inefficiencies have deterred widespread use of WCSP. Cost-benefit ratios of using WCSP would be greatly improved if a perennial sunflower were used instead of the annual types currently available. Perennial sunflower would reduce seed cost and planting cost, and perhaps lower opportunity costs, if able to thrive on poorer quality soils. In the near-term, scientists are focused on producing a perennial sunflower sufficiently productive to replace annual WCSP plantings. In 2013, scientists from the University of Minnesota, USDA-Agricultural Research Service, and USDA Wildlife Services National Wildlife Research Center evaluated a test plot of an open-pollinated variety of perennial sunflower resulting from genetic crossing of a domesticated annual species (Helianthus annuus) and a perennial wild species (H. tuberosus). Here, we report on results from the 2013 field test and discuss the outlook for development of perennial sunflower, which would help lessen damage to commercial sunflower when used in WCSP; provide a pesticide-free food source for beneficial insects, such as honey bees; help stabilize highly erodible lands near wetlands; and provide year-round habitat for wildlife. Lastly, we provide an initial strategy for using perennial sunflower to reduce blackbird damage in commercial sunflower.

Genomic relationships between hexaploid Helianthus resinosus and diploid Helianthus annuus (Asteraceae)

Genus Helianthus comprises diploid and polyploid species. An autoallopolyploid origin has been proposed for hexaploid species but the genomic relationships remain unclear. Mitotic and meiotic studies in annual Helianthus annuus (2n = 2x = 34) and perennial Helianthus resinosus (2n = 6x = 102) as well as the F1 hybrids between both species were carried out. Chromosome counting confirmed the hybrid origin of the latter plants and their tetraploid condition. Bivalents in hybrids ranged from 12 to 28 (\( \bar{x} \) = 20.8). Univalents, trivalents and quadrivalents were also observed. Meiotic products comprised dyads, triads and normal tetrads and pollen grains were heterogeneous in size. These observations suggest the occurrence of 2n pollen in addition to the expected n. Genomic in situ hybridization (GISH) of total H. annuus DNA on H. resinosus chromosomes rendered weak but uniform signals; similar hybridization pattern was observed using three other annual species. Hybridization with H. annuus probe performed on root tip cells of F1H. annuus × H. resinosus hybrids revealed 17 chromosomes with a strong hybridization signal. GISH in hybrid meiocytes distinguished chromosomes from parental species and revealed autosyndetic pairing of H. resinosus chromosomes, allosyndetic pairing in bivalents, trivalents and quadrivalents, and the presence of univalents derived from parents, H. annuus and H. resinosus. Results obtained from classical and molecular cytogenetics do not support H. annuus as a direct ancestor of H. resinosus. The occurrence of allosyndetic pairing and the relatively high fertility of the F1 hybrids point to the possibility that useful genes could be transferred from H. resinosus to cultivate sunflower, although the effective rate of recombination has not been evaluated. GISH method proved effective to recognize parental chromosomes in H. annuus × H. resinosus progeny.

Genome skimming reveals the origin of the Jerusalem Artichoke tuber crop species: neither from Jerusalem nor an artichoke

The perennial sunflower Helianthus tuberosus, known as Jerusalem Artichoke or Sunchoke, was cultivated in eastern North America before European contact. As such, it represents one of the few taxa that can support an independent origin of domestication in this region. Its tubers were adopted as a source of food and forage when the species was transferred to the Old World in the early 1600s, and are still used today. Despite the cultural and economic importance of this tuber crop species, its origin is debated. Competing hypotheses implicate the occurrence of polyploidization with or without hybridization, and list the annual sunflower H.annuus and five distantly related perennial sunflower species as potential parents. Here, we test these scenarios by skimming the genomes of diverse populations of Jerusalem Artichoke and its putative progenitors. We identify relationships among Helianthus taxa using complete plastomes (151551bp), partial mitochondrial genomes (196853bp) and 35S (8196bp) and 5S (514bp) ribosomal DNA. Our results refute the possibility that Jerusalem Artichoke is of H.annuus ancestry. We provide the first genetic evidence that this species originated recursively from perennial sunflowers of central-eastern North America via hybridization between tetraploid Hairy Sunflower and diploid Sawtooth Sunflower.

Evaluating an interspecific Helianthus annuus × Helianthus tuberosus population for use in a perennial sunflower breeding program

Perennial crops show promise for sustainable agricultural production while providing ecosystem services (maintaining healthy soil, controlling erosion, improving water quality, and enhancing wildlife habitat). Perennial crops could also provide economically viable cropping option to farmers. Sunflower (Helianthus annuus L.) is an ideal crop for perennialization because of existing genetic resources and a wide variety of end-uses. The objective of this research was to evaluate interspecific hybrids between perennial Helianthus tuberosus L. (2n=6x=102) and annual H. annuus L. (2n=2x=34) for perenniality and agronomic traits; assessing their utility in developing a perennial seed crop. Field trials indicated that seed yield traits were positively correlated with head traits. Tuber traits, which are required for perenniality, and seed yield traits were not correlated, indicating that simultaneous selection may be able to target high yielding lines that also tuberize. The F1 individuals were intermated for one generation and the intermated F1 (IM1F1) showed increases in head size (up to 20%) compared to the best F1 individual. The lack of correlation between tuber and seed traits coupled with phenotypic improvement after one generation of intermating suggest that the best improvement strategy for perennial sunflower is a recurrent selection program focusing on yield.

ТЕОРЕТИЧЕСКИЕ И ПРИКЛАДНЫЕ АСПЕКТЫ ОТДАЛЕННОЙ ГИБРИДИЗАЦИИ У ПОДСОЛНЕЧНИКА

The development of N.I. Vavilov concepts on distant hybridization as a way for broadening cultivated plants diversity is demonstrated on the example of sunflower. The review of studies on the crossability of cultivated sunflower with wild Helianthus species, the inheritance of characters in hybrid generations, the peculiarities of the genome structural and functional reorganizations in interspecific hybrid progenies is given. The practical results of the crosses between H. annuus and perennial Helianthus species are analyzed; the diverse aspects for application of this approach in sunflower breeding and genetics are discussed. With the use of distant hybridization a new model for investigation of nuclear-cytoplasmic interaction genetic mechanisms is suggested.

Natural selection drives clinal life history patterns in the perennial sunflower species, Helianthus maximiliani

In plants, ecologically important life history traits often display clinal patterns of population divergence. Such patterns can provide strong evidence for spatially varying selection across environmental gradients but also may result from nonselective processes, such as genetic drift, population bottlenecks and spatially restricted gene flow. Comparison of population differentiation in quantitative traits (measured as Q(ST) ) with neutral molecular markers (measured as F(ST) ) provides a useful tool for understanding the relative importance of adaptive and nonadaptive processes in the formation and maintenance of clinal variation. Here, we demonstrate the existence of geographic variation in key life history traits in the diploid perennial sunflower species Helianthus maximiliani across a broad latitudinal transect in North America. Strong population differentiation was found for days to flowering, growth rate and multiple size-related traits. Differentiation in these traits greatly exceeds neutral predictions, as determined both by partial Mantel tests and by comparisons of global Q(ST) values with theoretical F(ST) distributions. These findings indicate that clinal variation in these life history traits likely results from local adaptation driven by spatially heterogeneous environments.

Screening of wild helianthus species for resistance to high virulent Orobanche cumana Wallr., affecting sunflower in the Rostov region of the Russian Federation

SUMMARY During the last years in Rostov region of Russian Federation highly virulent biotypes of broomrape have propagated, affecting both hybrids of foreign breeding, and the native sunflower assortment, which used to be resistant earlier. Apart from that, the resistance of some known European sunflower types to broomrape races had disappeared, which testifies about the presence of the races F, G, H in the region at least. Consequently, the search of the sources of resistance is urgent. 14 samples of annual and 27 of perennial wild sunflower from the collection of Kuban experimental station VIR were tested for resistance to the most virulent broomrape population. From the annual species only H. petiolaris had weak degree of affection (1-3 tubercles/plant), while the other were affected to a high degree. The majority of perennial sunflower samples have shown the immunity. Perennial wild species of the sunflower of the same name that were used earlier in the research of Ruso et al . (1996) as resistant species against the Spanish populations of broomrape, show resistance also to high virulent O. cumana , which had propagated in the Rostov region of the Russian Federation. The immunity to broomrape of the studied wild perennial sunflower samples is not related to the absence of stimulating effect of root exudations on the seeds of the parasite. The immunity is more likely connected to physiologicalbiochemical features of cortex root cells.

Oil concentration and fatty acid profile of wild Helianthus species from the southeastern United States

Sunflower ( Helianthus annuus L.) oil has the potential to be improved for industrial and nutritional purposes through selection and breeding. The narrow genetic base of cultivated sunflower has been broadened and agronomic traits have been enhanced by the infusion of genes from wild species. Interest in using wild species in breeding programs has increased, but information about oil concentration and fatty acid composition is lacking for a number of rare and threatened species. The objective of this study was to evaluate achenes of seven wild sunflower species from the southeastern USA: H. eggertii, H. schweinitzii, H. porteri, H. verticillatus, H. smithii, H. angustifolius, and H. atrorubens, for oil concentration and fatty acid composition of four major fatty acids, palmitic, stearic, oleic, linoleic acids; and five minor acids, myristic, linolenic, arachidic, behenic, and lignoceric. Achenes of all populations were collected throughout the distributional range of the species. H. verticillatus had the highest oil concentration of the seven species with 323.4 g/kg, and was within the range reported for other wild perennial sunflower species. The average linoleic acid concentration in H. porteri of 817 g/kg is the highest concentration reported for a wild sunflower species. Linoleic acid concentrations for all seven species were higher than normally observed in populations grown in southern latitudes. The saturated palmitic and stearic fatty acids in H. porteri total 88 g/kg, about 30% less than cultivated sunflower oil with approximately 120 g/kg. The lower saturated fatty acid profile and the high linoleic concentration in the oil of H. porteri indicate that this species has the potential to reduce saturated fatty acids and increase linoleic acid concentration in traditional commercial sunflower oil. Further research will be needed to determine the inheritance of the fatty acids and oil concentration. Other agronomic traits will need to be maintained during the introgression of these traits into sunflower.

Gene transfer from wildHelianthusto sunflower: topicalities and limits

Sunflower (2n=17) belongs to the Helianthus genus (Asteraceae). Wild Helianthus species display morphological variation for branching and stem number, for architecture and seed size, and for resistance to abiotic and biotic stresses due to which they thrive in different environments in North America. The genus is divided into botanical sections, two for annual as sunflower, and two for perennial species as Jerusalem artichoke that produces rhizomes (tubers). We explain the difficulties and successes obtained by crossing sunflower with these species to improve the agronomic traits of the sunflower crop. It is easier to cross the annual species than the perennials’ with sunflower. Several traits such as Cytoplasmic male sterility and restorer Rf-PET1 genes, Downy mildew resistance, Phomopsis resistance, Sclerotinia resistance, Rust resistance, and Orobanche resistance have already been introduced from annual species into sunflower crop, but the complex genomic organization of these species compared to sunflower limits their important potential. Perennial species are much more diverse, and their genomes display 2n, 4n, or 6n chromosomes for n 17. The realities of inter-specific hybridization are relatively disappointing due to the introgression lines that have low oil and low seed yield. We report here several attempts to introgress agronomic traits from these species to sunflower, and we present as a case study, an introgressed progenies from H. mollis, a diploid species with sessile small leaves. We constructed a preliminary genetic map with AFLP markers in 21 BC1 plants, and we then showed that some progenies display 6 to 44% of introgression from H. mollis. Although this study is promising due to the novel compact architecture of the progenies, we cannot estimate the transferability from H. mollis to other perennial Helianthus to improve sunflower.

Analysis of transposons and repeat composition of the sunflower (Helianthus annuus L.) genome

A sample-sequencing strategy combined with slot-blot hybridization and FISH was used to study the composition of the repetitive component of the sunflower genome. One thousand six hundred thirty-eight sequences for a total of 954,517 bp were analyzed. The fraction of sequences that can be classified as repetitive using computational and hybridization approaches amounts to 62% in total. Almost two thirds remain as yet uncharacterized in nature. Of those characterized, most belong to the gypsy superfamily of LTR-retrotransposons. Unlike in other species, where single families can account for large fractions of the genome, it appears that no transposon family has been amplified to very high levels in sunflower. All other known classes of transposable elements were also found. One family of unknown nature (contig 61) was the most repeated in the sunflower genome. The evolution of the repetitive component in the Helianthus genus and in other Asteraceae was studied by comparative analysis of the hybridization of total genomic DNAs from these species to the sunflower small-insert library and compared to gene-based phylogeny. Very little similarity is observed between Helianthus species and two related Asteraceae species outside of the genus. Most repetitive elements are similar in annual and perennial Helianthus species indicating that sequence amplification largely predates such divergence. Gypsy-like elements are more represented in the annuals than in the perennials, while copia-like elements are similarly represented, attesting a different amplification history of the two superfamilies of LTR-retrotransposons in the Helianthus genus.

Widespread Occurrence of the Aecial Stage of Sunflower Rust Caused by Puccinia helianthi in North Dakota and Minnesota in 2008.

Sunflower rust caused by Puccinia helianthi (Schw.) is widespread in North America and occurs annually on cultivated sunflower (Helianthus annuus L.) and wild annual and perennial Helianthus spp., although severity on the U.S. sunflower crop has been increasing in recent years (2). P. helianthi is a autoecious, macrocyclic rust, but the aecial stage is rarely observed in the field (1,3,4). In most years, the earliest appearance of sunflower rust in North Dakota (ND) and surrounding states usually occurs in early August as the uredinial stage. Initial inoculum can result from urediniospores that overwinter in the Northern Great Plains, urediniospores blown in from areas south of North Dakota, or basidiospores completing the life cycle. However, aecia have been noted very infrequently and never widespread, indicating initial inoculum is usually urediniospores. Aecia of P. helianthi were first observed on 24 June 2008 in a commercial sunflower field (confection hybrid CHS 3126) near Mohall, ND. Aecia cups measuring 0.2 to 0.3 mm in diameter were observed in clusters that were 1 to 7 mm wide in diameter and containing as many as 150 cups. Aecia cups were bright orange but turned brown-black as they senesced. As many as 15 aecial clusters occurred on individual leaves or cotyledons. Aeciospores were ellipsoid, hyaline, and measured approximately 20 μm in diameter. On 4 July 2008, uredinia were first observed in the same Mohall, ND field. At that time, uredinia, aecia, and senesced aecia could all be found on the same leaves. In a non-fungicide-treated strip of the field, pustule coverage on the lower leaves was 10 to 20% by mid-July, pustule coverage on the upper four leaves of plants in the untreated strip was 56% by 27 August, and yield at harvest was less than 200 kg/ha. The rest of the field was sprayed twice with fungicides and yielded 1,571 kg/ha, which is similar to the statewide yield average of 1,573 kg/ha in 2008. To determine the prevalence of aecia in the primary growing regions of ND and Minnesota (MN), surveys were conducted in 75 sunflower fields in 18 counties between 22 and 24 July in ND and 34 fields in 8 counties between 17 and 31 July in MN. Incidence of aecia and uredinia were determined by visual observation of a minimum of 20 plants scouted in a 'W' pattern in the field. Rust was found in 31 and 53% of fields in ND and MN, respectively. In fields where rust was found, both aecia and uredinia were observed in 37% of the fields, aecia only in 29% of the fields, and uredinia only in 34% of the fields. Although it is uncertain why aecia were widespread in 2008, night temperatures in Mohall, ND, where aecia were first observed, reached the dew point temperature on 51 of 61 days in June and July, suggesting that dew or fog likely formed. Thus, favorable conditions for germination and infection early in the growing season indicate widespread occurrence of rust was likely a result of local inoculum sources. The early appearance of aecia is cause for concern for two reasons: significant yield loss can occur when rust appears early in the growing season; and the presence of aecia suggest that the pathogen completed its sexual cycle. When P. helianthi completes its life cycle it is likely that a greater diversity of races will result (4).

Wild species of Helianthus L.: Sources of resistance to the parasite Orobanche cumana Wallr.

SUMMARY Accessions from different Helianthus species, cultivated sunflower forms and interspecific hybrid forms and lines were included in this investigation. It was established that broomrape resistance was transferred from 11 perennial Helianthus species to interspecific hybrids developed on the basis of new sunflower lines. Some of the new lines possessed other desirable agronomical characters, which could be successfully transferred to new sunflower hybrid cultivars. Differences were observed in the origin of broomrapes found in different locations of northern Bulgaria. Diverse origin of some of the obtained sunflower forms was confirmed using the RAPD analysis.

Phylogenetic relationships between annual and perennial species of Helianthus: evolution of a tandem repeated DNA sequence and cytological hybridization experiments

The amplification and chromosomal localization of tandem repeated DNA sequences from Helianthus annuus (clone HAG004N15) and the physical organization of ribosomal DNA were studied in annual and perennial species of Helianthus. HAG004N15-related sequences, which did not show amplification in other Asteraceae except for Viguiera multiflora, were redundant in all the Helianthus species tested, but their frequency was significantly higher in perennials than in annuals. These sequences were located at the ends and intercalary regions of all chromosome pairs of annual species. A similar pattern was found in the perennials, but a metacentric pair in their complement was not labelled. Ribosomal cistrons were carried on two chromosome pairs in perennials and on three pairs in annuals except for H. annuus, where rDNA loci were on four pairs. No difference was observed between cultivated H. annuus and its wild accessions in the hybridization pattern of the HAG004N15 and ribosomal probes. These findings support the hypothesis that the separation between annual and perennial Helianthus species occurred through interspecific hybridization involving at least one different parent. However, GISH in H. annuus using genomic DNA from the perennial Helianthus giganteus as blocking DNA failed to reveal different genomic assets in annual and perennial species.

Saint Nathan

Saint Nathan

Root growth of interspecific sunflower seedlings derived from wild perennial sunflower species

Early root and hypocotyl growth and root branching patterns were characterized for five genetically diverse interspecific sunflower hybrids derived from wild perennial Helianthus species and two cultivated hybrids. Seedlings were grown in polyethylene pouches at 25 °C in the dark for 10 d. The hybrid and days after sowing (DAS) were sources of variation for primary and lateral root length, number of lateral roots, root branching density, root fresh weight, and hypocotyl length and fresh weight. There were high positive correlations among root growth characteristics that should be helpful in selecting sunflower hybrids adapted to arid conditions. The wild interspecific sunflower hybrids derived from wild perennial species possessed less-than-expected variability in early root growth. Nevertheless, there appears to be adequate genetic variability for further selection and genetic improvement. Key words: Helianthus species, growth pouch, primary roots, lateral roots, branching density, hypocotyl

First Report of Albugo tragopogonis on Cultivated Sunflower in North America.

White rust, caused by Albugo tragopogonis (Pers.) S.F. Gray, was observed on a few plants of both oilseed and confection sunflowers (Helianthus annuus L.) in northwestern Kansas (Cheyenne County) in 1992. The disease was observed again from 1993 to1995 in nine counties in western Kansas, with incidence per field ranging up to 35%. White rust was found only on late-planted fields in 1996 and 1997 and was not found at all from 1998 to 2001. White rust was also observed on cultivated and wild sunflower (H. annuus) for the first time in eastern Colorado (Kit Carson and Yuma counties) from 1994 to 1997, but was absent from 1998 to 2001. Leaf pustules on both cultivated and wild sunflowers were similar in appearance. Pustules were convex, chlorotic on the upper side of the leaf, and concave and dull white on the under side of the leaf. Pustules on cultivated sunflower were generally limited to three to six leaves in the middle of the plant and affected 10 to 40% of the leaf area. Sporangial dimensions fell within the reported dimensions for A. tragopogonis (2). In 1997, water-soaked lesions 1 to 2 cm long containing oospores of A. tragopogonia were observed on the lower to middle portions of stems of cultivated sunflower in western Kansas and the adjacent area of Colorado. Stem lesions were observed much less frequently than foliar lesions and only in 1997. Sporangia were not observed in stem lesions, nor were any other fungi isolated from these lesions. To our knowledge, this is the first report of white rust occurring on cultivated sunflower in any production area of North America; the disease has not been observed in the major U.S. sunflower production area of North Dakota, South Dakota, and Minnesota. Foliar white rust lesions generally have little economic impact on sunflower, but the presence of stem lesions is significant because stem lesions may lead to lodging (3). Lodging due to A. tragopogonia was not observed in either Kansas or Colorado. White rust has previously only been reported on wild H. annuus in Wisconsin and on perennial Helianthus spp. in Missouri and Illinois (1).

Occurrence of partial hybrids in wide crosses between sunflower (Helianthus annuus) and perennial species H. mollis and H. orgyalis

Hybridisation between the annual diploid sunflower ( Helianthus annuus)and the perennial diploid species Helianthus mollis and Helianthus orgyalis was obtained by means of a normal crossing procedure or embryo rescue. Hybridisation success was low. All plants examined cytologically appeared to be diploid. However, the phenotypes of these diploids were not intermediate between the parents and, despite great variation, they resembled the female parent-type predominantly. Thirty five percent of plants issued from sunflower pollinated with perennial Helianthus had a phenotype resembling the female sunflower parent. On average, only 5% of the minimum number of expected RAPD and RFLP bands from male parents were recovered in plants produced from mature seeds after pollination of sunflower by H. mollis. More hybrids were found among plants obtained from embryo rescue, with an average of 25% of the male parent bands recovered per plant. Analysis of individual plants indicated the occurrence of various levels of hybridisation. There was a significant positive correlation between the number of phenotype traits related to hybrid status and the number of bands derived from the male parent. A single hybrid plant might possibly represent the product of a 'normal' hybridisation event. The mechanisms behind these unusual events and the consequences for the breeder are discussed.

Partial hybridization in crosses between cultivated sunflower and the perennial Helianthus mollis: effect of in vitro culture compared to natural crosses

Eighty-four plants obtained from the pollination of the annual diploid cultivated sunflower, Helianthus annuus, by the perennial diploid species H. mollis were obtained naturally from mature seeds (62 plants) or following embryo rescue procedures (22 plants) and subsequently studied for phenotype traits and DNA markers. Twenty-two plants were obtained from the reverse cross as a result of natural seed development. The level of hybridization was determined using random amplified polymorphic DNA and restriction fragment length polymorphism markers. All of the resulting plants were found to be diploid 2n=34. Reciprocal crosses led to different progenies, with phenotypes that were predominantly similar to that of the female sunflower or the H. mollis type. The embryo rescue procedure enhanced the level of hybridization, whereas natural seed development led to fewer hybrids. Molecular markers unique to the female or the male parent indicated mechanisms leading to partial hybridization.

Sources of resistance to Sclerotinia sclerotiorum (Lib) de Bary in a natural Helianthus gene pool

SUMMARY Sclerotinia sclerotiorum (Lib.) de Bary is one of the major diseases of sunflower (Helianthus annuus). The pathogen can attack all parts of the plant at every stage of plant growth, predominantly the capitulum, leaf and stem. In the present study, several perennial Helianthus species of diverse origin were evaluated for resistance level to mid-stem and leaf infection using an inoculation method. The evaluation revealed considerable and significant differences among the genotypes in all recorded resistance traits. Three genotypes showed enhanced resistance levels to mid-stem reaction. Two genotypes exhibit resistances to leaf infection. Since all evaluated resistant genotypes in these trials are sexually incompatible with the Helianthus annuus genome, newly developed biotechnological methods gain particular importance for the transfer of the discovered levels of resistance into the cultivated sunflower.