Search

Over the past 40 years, confection sunflower in China has achieved significant improvements from old landraces to open-pollinated varieties (OPV) through conventional breeding. Starting in 2010, after a short period of growing U.S. hybrids, superior Chinese proprietary hybrids were developed through contributions from both the private and public sectors utilizing old landraces, OPV and limited foreign germplasms as genetic resources which eventually enabled China to become a leading producer worldwide. The average yields have steadily increased from 1730 kg/ha (OPV) to over 2700 kg/ha (hybrid) largely due to genetic improvements and advanced cultivation practices. The planted area is expected to remain at around 0.60 M ha, with over 95% confection sunflower, and the remaining 5% oilseed type. Sunflower production in China is mainly concentrated in 10 provinces of the northwest region with around three-fourth of the production in Inner Mongolia, followed by Xinjiang. The potential for increased sunflower cultivation remains optimistic in those regions due to the benefit of an established industrial supply chain of producing, processing, and marketing near the production areas. More than half of all products is domestically consumed (∼2.0 M T/year), but overseas exports have gradually increased in recent years. Future directions for confection sunflower breeding should continue emphasizing high quality, multi-disease resistance, and product versatility to meet the diverse market demands. Further enhancement of variety registration and the implementation of DNA fingerprinting for variety identification will help the sustainable development of the Chinese sunflower industry.

Eggplant (Solanum melongena L.) is one of the most popular common major vegetable crops worldwide. This study evaluated the nutritional content of seven commercial eggplant fruits in terms of fatty acid, mineral, sugar, organic acid, amino acid and polyamine contents. The most abundant fatty acid was linoleic acid (range, 39.14-53.81%, ave. 45%), and the most abundant mineral was K (range, 1556.2-3171.6 mg/kg fw, ave. 2331.9). The major organic acid was malic acid (range, 129.87-387.01 mg/g fw, ave. 157.49), and the major sugar was fructose (range, 1242.81- 1379.77 mg/100 g fw, ave. 1350.88). The major polyamine was putrescine (11.54 and 25.70 nmol/g fw, ave. 17.86), and the major amino acid was glutamine (148.4 and 298.75 mg/100 g fw, ave. 219.74). Overall, taking into account the export potential of eggplants, these results may contribute to further studies aiming to improve other nutrient-rich varieties of eggplant in breeding programs.

Modern breeding of sunflower (Helianthus annuus L.), which started 100 years ago, increased the number and the diversity of cultivated forms. In addition, for more than 50 years, wild sunflower and other Helianthus species have been collected in North America where they all originated. Collections of both cultivated and wild forms are maintained in gene banks in many countries where sunflower is an important crop, with some specificity according to the availability of germplasm and to local research and breeding programmes. Cultivated material includes land races, open pollinated varieties, synthetics and inbred lines. The majority of wild accessions are ecotypes of wild Helianthus annuus, but also 52 other species of Helianthus and a few related genera. The activities of three gene banks, in USA, France and Serbia, are described in detail, supplemented by data from seven other countries. Past and future uses of the genetic resources for environmental adaptation and breeding are discussed in relation to genomic and improved phenotypic knowledge of the cultivated and wild accessions available in the gene banks.

Downy mildew (DM) and rust are two major global sunflower (Helianthin annuus L.) diseases causing significant yield losses and reducing seed quality. Host plant resistance mediated by dominant race‐specific genes has been extensively used in sunflower production to control these diseases. However, the considerable variability of the DM and rust pathogens caused by mutation or recombination has changed the dynamics of the diseases, significantly increasing their incidence in recent years. This necessitates the development and release of sunflower germplasm with enhanced levels of disease resistance. Germplasm lines HA‐DM12 (Reg. no. GP‐382, PI 700006), HA‐DM13 (Reg. no. GP‐383, PI 700007), and HA‐DM14 (Reg. no. GP‐384, PI 700008), all with multiple DM and rust resistance, were developed using phenotypic evaluation and marker‐assisted selection. The three lines share a common DM gene (PlArg) and a rust gene (R12) and a combination of different DM genes (Pl8, Pl17, and Pl18, respectively). The triple‐gene pyramids—HA‐DM12 (Pl8Pl8/PlArgPlArg/R12R12), HA‐DM13 (Pl17Pl17/PlArgPlArg/R12R12), and HA‐DM14 (Pl18Pl18/PlArgPlArg/R12R12)—confer comprehensive resistance to all races of DM and rust identified so far and can be used in sunflower breeding programs to develop hybrids with durable resistance to DM and rust. Core Ideas: Three oilseed sunflower germplasms with resistance to downy mildew and rust were developed using marker‐assisted selection.HA‐DM12, HA‐DM13, and HA‐DM14 each pyramided two different downy mildew R genes and one rust R gene.All germplasms confer comprehensive resistance to all races of downy mildew and rust identified so far. [ABSTRACT FROM AUTHOR]

Wild Helianthus species have been undeniably beneficial in sustaining the sunflower crop by providing plant breeders with a diverse genetic pool of potentially useful traits. Exploration to collect populations of wild sunflowers is one of the more difficult and challenging activities in the conservation and utilization of these valuable genetic resources. The logistics of collecting requires careful planning, locating the target species, obtaining permission to access and collect, and timing the exploration to ensure the availability of mature seed. The US Department of Agriculture, Agricultural Research Service (USDA-ARS) established the wild Helianthus seed collection in 1976 at Bushland, Texas with the goal of collecting and conserving the broadest representative genetic diversity possible and serving as a central repository of germplasm and related information. In 1985 this collection was transferred to UDSA-ARS, North Central Regional Plant Introduction Station, Ames, Iowa. Over the last half century, 37 explorations were undertaken covering 175,000 km to collect the 53 Helianthus species from their distributional ranges in the forty-eight conterminous states in the US, three Canadian Providences (Manitoba, Saskatchewan, and Alberta), Argentina and Australia. The many explorations have created a global crop wild relatives (CWR) genebank collection. The current wild CWR sunflower genebank contains 2562 accessions of 53 species with 1065 wild Helianthus annuus accessions (42 %), 617 accessions representing populations of the 13 other wild annual species (24 %), and 880 accessions representing 39 perennial species (34 %). This collection is the largest and most genetically diverse ex situ sunflower collection in the world and is vital to the conservation of wild sunflower species for the global sunflower community. [ABSTRACT FROM AUTHOR]

Cytoplasmic male-sterile line CMS ANN3 was discovered from a wild annual Helianthus annuus L. accession PI 413180. A single dominant fertility restoration (Rf) gene for CMS ANN3 was identified in PI 413180, P 21, RHA 801, RCMG 1, and RHA 280, designated as Rf9. This study reports the mapping of the Rf9 locus using an F2 population of 160 individuals. Bulked segregant analysis with SSR primers identified two polymorphic SSR markers in linkage group 3 of the sunflower genetic map. A linkage map of Rf9 was constructed with 16 markers including 11 SSR/STS and five SNP markers, covering a genetic distance of 87.3 cM. The Rf9 gene is located between a co-dominant marker ORS1114 and a dominant marker NSA002021, with a distance of 4.1 and 1.0 cM, respectively. The physical distance between the two closest flanking markers corresponds to 1.44 and 2.05 Mb on the HA 412-HO and XRQ assemblies, respectively. The closely linked marker for Rf9 will facilitate marker-assisted selection in breeding programs, which provides a basis for further characterization of this gene, and for studying the mechanism between cytoplasmic male sterility and Rf genes. The mapping of the Rf gene will also be useful for studying Rf gene suppression and nuclear–cytoplasm interactions. [ABSTRACT FROM AUTHOR]

One of the potential uses of Jerusalem artichoke (Helianthus tuberosus L.) is as a forage crop. Information on inherent differences in forage nutritional quality is essential if the quality of the forage is to be improved through breeding. The objectives of this study were to determine the genotypic variability among and within wild Jerusalem artichoke populations for the concentration of N, P, Ca, Mg, K, and the Ca/P ratio in the forage at flowering, estimate the magnitude of genotype x environment interaction, and examine relationships among mineral concentrations in the forage. Nine wild Jerusalem artichoke populations grown in an irrigated field nursery at Bushland, TX, were evaluated for N, P, Ca, Mg, K, and the Ca/P ratio in the forage at flowering over a 2-yr period. Population, year x population, and error variances were estimated to calculate the phenotypic variance. Estimates of the within-population variances were also determined. The adequacy of Jerusalem artichoke forage at flowering for maintenance of a ruminant animal was classified as follows: N, Ca, Mg, and K as adequate, P inadequate, and the Ca/P ratio as excessive. There were genotypic differences among the nine populations for N, K, P, Ca, Mg, and the Ca/P ratio for both years and averaged across years. The magnitude of the genotypic variance components indicated that a substantial proportion of the total variation for these elements was due to genotype, indicating the possibility of improvement through hybridization and selection. Within-population variation for N, Ca, and K was high, indicating potential for improvement with further selection within populations. Population variances for P and Mg were low, suggesting it will be difficult to improve these with selection. Unfortunately, P is inadequate in the forage to begin with, and our data indicated that selecting within populations for high P may not he very successful., JERUSALEM ARTICHOKE, a perennial species native to North America, is often present as a weed in pastures (Crawford et al., 1969) and crops (Wyse et al., 1986; Wall et al., [...]

Rust and downy mildew (DM) are two of the most important sunflower diseases in the world. The development of sunflower hybrids with enhanced levels of genetic resistance to both diseases is a goal for sunflower breeding. Four oilseed sunflower (Helianthus annuus L.) germplasm lines, HA‐R14 (Reg. no. GP‐371, PI 698193), HA‐R15 (Reg. no. GP‐372, PI 698194), HA‐R16 (Reg. no. GP‐373, PI 698195), and HA‐R17 (Reg. no. GP‐374, PI 698196) are multiple rust‐ and DM‐resistant lines that were developed and released by the USDA‐ARS Sunflower and Plant Biology Research Unit in collaboration with the North Dakota Agricultural Experiment Station in January 2020. Three lines, HA‐R14 (R4R4/R12R12/PlArgPlArg), HA‐R15 (R5R5/R12R12/PlArgPlArg), and HA‐R16 (R13bR13b/R12R12/PlArgPlArg), stack two different rust genes with a common DM gene PlArg, and HA‐R17 (R13bR13b/R15R15) possesses two rust genes, R13b and R15. These germplasm lines will provide a broad spectrum of useful sources of resistance to all known races of rust and DM. Core Ideas: Four oilseed sunflower germplasm lines with dual disease resistance were developed by MAS.HA‐R14, HA‐R15, and HA‐R16 combine two different rust R genes and a downy mildew R gene.All germplasm exhibited resistance to all known races of rust and downy mildew.HA‐R17 combined two different rust R genes resistant to all known races of rust. [ABSTRACT FROM AUTHOR]

Crop-to-wild hybridization has the potential to introduce beneficial traits into wild populations. Gene flow from genetically engineered crops, in particular, can transfer genes coding for traits such as resistance to herbicides, insect herbivores, disease, and environmental stress into wild plants. Cultivated sunflower (Helianthus annuus) hybridizes spontaneously with wild/weedy populations (also H. annuus), but little is known about the relative fitness of [F.sub.1] hybrids. In order to assess the ease with which crop-to-wild introgression can proceed, we compared characteristics of [F.sub.1] wild-crop progeny with those of purely wild genotypes. Two nontransgenic, cultivated varieties were crossed with wild plants from three different regions - Texas, Kansas, and North Dakota. Seed burial experiments in the region of origin showed that wild-crop seeds had somewhat higher germination rates (less dormancy) than wild seeds from Kansas and North Dakota, while no differences were seen in seeds from Texas. Progeny from each type of cross were grown in outdoor pots in Ohio and in a weedy field in Kansas to quantify lifetime fecundity and flowering phenology. Flowering periods of hybrid and wild progeny overlapped considerably, especially in plants from North Dakota and Texas, suggesting that these hybrids are very likely to backcross with wild plants. In general, hybrid plants had fewer branches, flower heads, and seeds than wild plants, but in two crosses the fecundity of hybrids was not significantly different from that of purely wild plants. In Ohio, wild-crop hybrids from North Dakota appeared to be resistant to a rust that infected 53 % of the purely wild progeny, indicating a possible benefit of 'traditional' crop genes. In summary, our results suggest that [F.sub.1] wild-crop hybrids had lower fitness than wild genotypes, especially when grown under favorable conditions, but the [F.sub.1] barrier to the introgression of crop genes is quite permeable. Key words: Asteraceae; crop-weed hybrids; fecundity; fitness; flowering phenology; gene flow; introgression; seed dormancy; sunflower.

The sexual transfer of genes between taxa possessing different structural karyotypes must involve the passage of genes through a chromosomal sterility barrier. Yet little is known about the effects of structural differences on gene introgression within or adjacent to the rearranged chromosomal fragments or about the patterns of introgression in collinear regions. Here, we employ 197 mapped molecular markers to study the effects of chromosomal structural differences on introgression in backcrossed progeny of the domesticated sunflower, Helianthus annuus, and its karyotypically divergent wild relative, H. petiolaris. Forty percent of the genome from the seven collinear linkages introgressed, whereas only 2.4% of the genome from the 10 rearranged linkages was transferred. Thus, chromosomal rearrangements appear to provide an effective mechanism for reducing or eliminating introgression in rearranged chromosomal segments. On the other hand, observations that 60% of the markers from within the collinear portion of the genome did not introgress suggests that genic factors also resist introgression in Helianthus. That is, selection against H. petiolaris genes in concert with linkage may have reduced or eliminated parts of the genome not protected by structural changes. Thus, barriers to introgression in Helianthus appear to include both chromosomal structural and genic factors.