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A 10-day trip, encompassing 4600 km in the southeastern USA states of Tennessee, North Carolina, South Carolina, Georgia and Alabama, was made in October, 2003. Our primary objective was to locate populations of Helianthus eggertii, then on the USDI, Fish and Wildlife Service Threatened and Endangered Species list, and H. verticillatus, a candidate for endangered species status. Helianthus eggertii has since been de-listed (August 2005). An additional objective was to collect seeds of H. porteri, a species reclassified from Viguiera porteri, which is endemic to granite rock outcrops in Georgia. We collected seeds from 27 populations of the above three species plus three additional species, H. angustifolius, H. atrorubens, and H. smithii. Seed was deposited with the USDA-ARS North Central Regional Plant Introduction Station at Ames, Iowa (NCRPIS) from which 24 of the 27 collections are available for distribution. The three 'target' species were represented by 13 collections of H. eggertii, eight of H. porteri, and two of H. verticillatus; none of the three species were previously available from the NCRPIS sunflower collection. The availability of seed of these three species will allow researchers around the world the opportunity to investigate the potential of these wild Helianthus species to contribute useful traits to cultivated sunflower. Complete collection data has been loaded into the USDA-ARS Germplasm Resource Information Network (GRIN), and is available on the internet (www.ars-grin.gov). [ABSTRACT FROM AUTHOR]

The ability of some sunflower species to survive and thrive in shifting sand dunes with an annual precipitation of 50 mm could be of value for cultivated sunflower, a crop often grown in arid regions. The genus Helianthus comprises 51 species and 19 subspecies, with 14 annual and 37 perennial species, all native to North America. The objective of this study was to collect achenes from as many populations as possible of desert species, specifically annual H. anomalus, H. deserticola, H. niveus ssp. canescens, and perennial H. niveus ssp. tephrodes from the desert southwestern USA and make them available for future research and improvement of cultivated sunflower. The first exploration for H. anomalus and H. deserticola took place from September 16 to 23, 2000, covering 4100 km in three states, Utah, Arizona, and Nevada; while the second exploration concentrated on H. deserticola populations in west central Nevada, taking place between June 20 to 23 and August 15 to 18, 2005. The third exploration for H. niveus ssp. tephrodes took place from February 26 through March 5, 2005, covering 2200 km in southern California and adjacent Arizona. Only one population of H. deserticola from Utah and two populations of H. anomalus from Utah were collected in 2000. The 2005 exploration in Nevada resulted in the collection of achenes from 13 populations of H. deserticola. In 2005, five populations of H. niveus ssp. tephrodes were collected from the Alogodones Dunes in California. One population of H. niveus ssp. canescens was collected from Yuma, Arizona, near the US-Mexico border, with three additional populations collected from the Pinta Sands area of Arizona, which is the northernmost extension of the Gran Desierto of Sonora, Mexico. Achene samples of each collection are maintained and distributed from the USDA-ARS National Plant Germplasm System, North Central Regional Plant Introduction Station, Ames, Iowa. The limited number of desert species populations collected will provide basic germplasm for further research dealing with improving drought tolerance in cultivated sunflower. [ABSTRACT FROM AUTHOR]

A total of 82 isolates of Plasmopara halsredii, collected from all production areas of Hungary between 1976 and 1993, were assessed for their virulence pattern on a standard set of sunflower differentials under glasshouse conditions. The isolates were classified into six pathogenic races each representing a particular virulence phenotype. From 1976 until 1988 all the isolates were found to be virulent only on sunflowers possessing no known resistance genes, thus classified as race I. There was an apparent shift in the virulence of the P. halstedii population collected after 1988. Six races (1 2, 3. 4. 8 and 9) were identified among the 45 samples collected between 1989 and 1993, with races 1 and 3 predominant, at a frequency of 35% each. While the increase in race virulence is undoubtedly due to selection imposed by resistant hybrids, the origin of the new races is unknown. Whether new races have arisen from the indigenous P. halstedii population, or whether they have been imported from abroad, can only be reliably determined by DNA techniques, such as fingerprinting. [ABSTRACT FROM AUTHOR]

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The article presents the registration of two maintainer and three restorer Sclerotinia-tolerant oilseed sunflower germplasms. The two maintainers include HA 451 and HA 452. Two maintainer and three restorer oilseed sunflower germplasms were developed and released by the Agricultural Research Service of the U.S. Department of Agriculture and the North Dakota Agriculture Experiment Station. These germplasms were selected for their tolerance to Sclerotinia head and stalk rot which is a major sunflower disease. They also provide diversity for agronomic characteristics and oil quality. These germplasms are available for use by industry and public researchers to create hybrids, parental lines, or germplasms with increased tolerance to Sclerotinia head and stalk rot.

The article presents the registration of the Three Virus Resistant Sunflower Genetic Stocks, developed and released by the U.S. Department of Agriculture-Agricultural Research Service and the North Dakota Agricultural Experiment Station.

The article reports on the registration of HA 444, HA 445 and HA 446, maintainer and RHA 447, restorer on high oleic oilseed sunflower germplasms developed by the United States Department of Agriculture-ARD, Fargo and the North Dakota Agricultural Experiment Station in North Dakota. These germplasms have a high-oleic fatty acid concentration that is intended to be used by the sunflower industry and the public researchers. HA 44 is derived from F6 to F7 maintainer line which is selected from the cross HA 434/HA 406. The pedigree breeding method used to develop HA 444, HA 455, and HA 446 are the same. While RHA 447 is derived from F7 to F8 restorer line which is selected from the cross RHA 377/ RHA 348.

The article reports on the registration of HA 442, imidazolinone herbicide-resistant maintainer and RHA 443, fertility restorer of the oilseed sunflower germplasms developed by United States Department of Agriculture-ARD, Fargo and the North Dakota Agricultural Experiment Station in North Dakota. These germplasms were developed as the resistant to the imidazoline herbicide imazamox intended to be used by the sunflower industry and the public researchers. The HA 442 is derived from F6 to F7 maintainer lines which are selected from the cross HA 425/87CAEB//HA434/HA 412 with a high oleic fatty acid concentration. While RHA 443 was derived from F6 to F7 restorer line which is selected for the cross RHA 426/RHA 419//RHA 377/AS 4379.

The article reports on the registration of RHA 439, RHA 440, restorer and HA 441, sclerotinia tolerant oilseed sunflower germplasms developed by the United State Department of Agriculture-ARS, Fargo and North Dakota Agricultural Experiment Station in North Dakota. These germplasms are used to create hybrids and parental lines with improved Sclerotinia intended for the use of the sunflower industry and public researchers. The RHA 439 was derived from F7 to F8 restorer line selected from the cross RHA 377/AS 3211. The lines of RHA 439 and RHA 440 was selected by evaluating the testcross hybrids that were artificially inoculated under the mist irrigation. While 441 was derived from F7 to F8 maintainer lines that were selected form the cross of HA 412/SD.

The article presents the registration of three maintainer oilseed sunflower germplasms. The three maintainers include HA 456, HA 457 and HA 412 HO. The germplasms were developed and released by the Agricultural Research Service of the U.S. Department of Agriculture, and the North Dakota Agricultural Experiment Station. These high-oleic germplasms are available for use by industry and public researchers to create hybrid, parental lines, or germplasms with a midoleic or high-oleic fatty acid concentration in the oil.

The article presents the registration of a sunflower germplasm resistant to rust, downy mildew, and virus, developed and released by the U.S. Department of Agriculture-Agricultural Research Service and the North Dakota Agricultural Experiment Station.

Downy mildew of sunflower (Helianthus annuus L.), caused by the pathogen Plasmopara halstedii, is a potentially devastating disease. Seventy-seven isolates of P. halstedii collected in twelve countries from four continents were investigated for RAPD polymorphism with 21 primers. The study led to a binary matrix, which was subjected to various complementary analyses. This is the first report on the international genetic diversity of the pathogen. Similarity indices ranged from 89% to 100%. Neither a consensus unweighted pair group method with arithmetic means (UPGMA) tree constructed after bootstrap resampling of markers nor a principal component analysis based on distance matrix revealed very consistent clusterings of the isolates, and groups did not fit race or geographical origins. Phylogenies were probably obscured by limited diversity. Analysis of molecular variance (AMOVA) and Nei's genetic diversity statistics gave similar conclusions. Most of the genetic diversity was attributable to individual differences. The most differentiated races also had the lowest within-diversity indices, which suggest that they appeared recently with strong bottleneck effects. Our analyses suggest that this pathogen is probably homothallic or has an asexual mode of reproduction and that gene flow among countries can occur through commercial exchanges. Knowledge of the downy mildew populations' structure at the international level will help to devise strategies for controlling this potentially devastating disease.

ABSTRACT Sunflower mosaic is caused by a putative member of the family Potyviridae. Sunflower mosaic virus (SuMV) was characterized in terms of host range, physical and biological characteristics, and partial nucleotide and amino acid sequence. Cells infected with SuMV had cytoplasmic inclusion bodies typical of potyviruses. Of 74 genera tested, only species in Helianthus, Sanvitalia, and Zinnia, all Asteraceae, were systemic hosts. Commercial sunflower hybrids from the United States, Europe, and South Africa were all equally susceptible. The mean length of purified particles is approximately 723 nm. The virus was transmitted by Myzus persicae and Capitphorus elaegni, and also was seedborne in at least one sunflower cultivar. Indirect enzyme-linked immunosorbent assay tests with a broad-spectrum potyvirus monoclonal antibody were strongly positive. SuMV-specific polyclonal antisera recognized SuMV and, to a lesser extent, Tobacco etch virus (TEV). When tested against a panel of 31 potyvirus-differentiating monoclonal antibodies, SuMV was distinct from any potyvirus previously tested. SuMV shared four epitopes with TEV, but had a reaction profile more similar to Tulip breaking virus (TBV). SuMV did not possess epitopes unique only to TBV. The predicted coat protein had a molecular weight of 30.5 kDa. The 3' end of the virus genome was cloned and sequenced. Phylogenetic analysis of the coat protein amino acid sequence revealed that SuMV is a distinct species within the family Potyviridae, most closely related to TEV.

Resistance to Phomopsis sp. (Diaporthe sp.) brown/gray stem spot was confirmed by screening sunflower calli on shoot induction media amended with fungal filtrate. Calli of sunflower genotypes OCMS 74 and NS-H-45, which show resistance to the disease in field trials, remained viable on media with 15% (v/v) fungal filtrate, while calli of field susceptible genotypes RHA 273 and PAG/SF 103 were killed on media with as little as 7.5% fungal filtrate. Fresh weight of calli of all genotypes was significantly reduced by 2.5% fungal filtrate, and calli of all genotypes were killed by filtrate concentrations of 20%. These in vitro results corroborate prior field observations for disease reaction of these genotypes.