Wild Sunflower Research Articles

Population-aware permutation-based significance thresholds for genome-wide association studies

Abstract Motivation Permutation-based significance thresholds have been shown to be a robust alternative to classical Bonferroni significance thresholds in genome-wide association studies for skewed phenotype distributions. The recently published method permGWAS introduced a batch-wise approach to efficiently compute permutation-based genome-wide association studies. However, running multiple univariate tests in parallel leads to many repetitive computations and increased computational resources. More importantly, traditional permutation methods that permute only the phenotype break the underlying population structure. Results We propose permGWAS2, an improved method that does not break the population structure during permutations and uses an elegant block matrix decomposition to optimize computations, thereby reducing redundancies. We show on synthetic data that this improved approach yields a lower false discovery rate for skewed phenotype distributions compared to the previous version and the commonly used Bonferroni correction. In addition, we re-analyze a dataset covering phenotypic variation in 86 traits in a population of 615 wild sunflowers (Helianthus annuus L.). This led to the identification of dozens of novel associations with putatively adaptive traits, and removed several likely false-positive associations with limited biological support. Availability permGWAS2 is open-source and publicly available on GitHub for download: https://github.com/grimmlab/permGWAS. Supplementary information Supplementary data are available at Bioinformatics Advances online.

Admixture With Cultivated Sunflower Likely Facilitated Establishment and Spread of Wild Sunflower (Helianthus annuus) in Argentina.

A better understanding of the genetic and ecological factors underlying successful invasions is critical to mitigate the negative impacts of invasive species. Here, we study the invasion history of Helianthus annuus populations from Argentina, with particular emphasis on the role of post-introduction admixture with cultivated sunflower (also H. annuus) and climate adaptation driven by large haploblocks. We conducted genotyping-by-sequencing of samples of wild populations as well as Argentinian cultivars and compared them with wild (including related annual Helianthus species) and cultivated samples from the native range. We also characterised samples for 11 known haploblocks associated with environmental variation in native populations to test whether haploblocks contributed to invasion success. Population genomics analyses supported two independent geographic sources for Argentinian populations, the central United States and Texas, but no significant contribution of related annual Helianthus species. We found pervasive admixture with cultivated sunflower, likely as result of post-introduction hybridization. Genomic scans between invasive populations and their native sources identified multiple genomic regions of divergence, possibly indicative of selection, in the invaded range. These regions significantly overlapped between the two native-invasive comparisons and showed disproportionally high crop ancestry, suggesting that crop alleles contributed to invasion success. We did not find evidence of climate adaptation mediated by haploblocks, yet outliers of genome scans were enriched in haploblock regions and, for at least two haploblocks, the cultivar haplotype was favoured in Argentina. Our results show that admixture with cultivated sunflower played a major role in the establishment and spread of H. annuus populations in Argentina.

Honey bee (Apis mellifera L.) foraging rewards in sunflowers: effect of floral traits on visitation and variation in pollen quality over two consecutive years

Sunflower production depends on pollination by honey bees, Apis mellifera L., and wild bees. For wild sunflower oligoleges, preference for various sunflower lines seems to reflect the quantity (or accessibility) of floral rewards, with floret size (≈accessibility of sunflower nectar) appearing most important. However, it is less clear how honey bees, a key generalist, are affected by sunflower floral traits. The honey bee-sunflower interaction was explored to test if accessibility of nectar (≈floret size) and related floral traits explain foraging preferences and to assess potential nutritional variation in sunflower pollen. In the first two years, honey bee foraging preference increased with decreasing floret length similar to previous observations with wild pollinators. In the second year, no similar response was seen, though nectar rewards (by volume or volume × concentration) were remarkably low compared to the previous year. Pollen collected from bagged plants in the second year showed sunflower lines differed in concentrations (µg/mg ± SE) of total fatty acids and essential fatty acids. In general, it appears that honey bee responses to floral traits are similar to those of wild bees responsible for pollinating much of the sunflower crop in the central United States and that variation in the nutritional quality of sunflower pollen is greater than previously known. Because of the broad geographic distribution of the sunflower crop, additional research on how the environment influences floral rewards and sunflower-pollinator interactions may be needed.

Characterization of Argentinian wild Helianthus annuus populations in their responses to Plasmopara halstedii infection

The pathogen Plasmopara halstedii, causing downy mildew (DM), is a widespread sunflower disease which can be controlled by single dominant genes. Wild Helianthus annuus have been a valuable source of vertical resistance to control P. halstedii, but such resistance may eventually be overcome by new races of the pathogen. Alternatively, quantitative, or partial resistance, is more stable and may be combined with vertical resistance to prevent DM outbreaks. We assessed the responses of six populations of wild H. annuus naturalized in Argentina to race 710 of P. halstedii. We examined: 1) the aerial phenotype (including seedling death) using two damage scales and three disease indices, 2) the growth of the pathogen along the hypocotyls, and 3) the presence of the pathogen in the root system. We found that the evaluated sunflower wild populations had lower disease levels than the susceptible cultivated controls. A histologic analysis showed that the wild H. annuus seedlings showed cellular reactions (e.g. necrosis and the deposit of materials on the walls of invaded cells) to restrict the pathogen’s growth, allowing the identification of two possible types of resistance: type I, when the growth of the pathogen was limited to the base of the hypocotyls, and type II, when the pathogen managed to invade the entire length of the hypocotyls. The wild sunflower populations also showed differential responses to root infections. A quantitative or partial genetic resistance, rather than resistance based on major genes, seems to be operating in the sampled populations. The individuals found to be resistant in each population represent promising germplasm for sunflower breeding.

Изпитване на образци диви видове слънчоглед за устойчивост към Phomopsis helianthi

The aim of the present study was to determine the presence of genes for resistance to gray spots in sunflower /Phomopsis helianthi Munt. Cvet. еt al./ in wild species of genus Helianthus. The study included accessions of wild annual Helianthus annuus L. (w.f.) and some perennial wild Helianthus species, preserved and maintained in the ex-situ collection at the DAI, General Toshevo. Two isolates of the pathogen were used for infection- Ph 21-6214 and Ph21-211, with each of which three plants from each sample were infected according to a 3x2 scheme. The plants‘ reaction was checked 21 days after inoculation on a nine-ball scale. High resistance (VR) to both pathogen isolates was found in 9 samples of Helianthus annuus L. (w.f.) and in 2 accessions of the perennials H. mollis and H. resinosus. Resistance (R) to both pathogen isolates was shown by two samples from the annual and one from the perennial species. Five samples of Helianthus annuus L. (w.f.) were found to be resistant to pathogen isolate Ph21-6214 and the same number to pathogen isolate Ph21-211. From the obtained results, it could be concluded that the observed reactions of high resistance and resistance in samples from wild species of sunflower can be successfully used as potential sources of genes for resistance to the pathogen in sunflower breeding.

Effects of Pre-Emergence Herbicides on Weed Control and Yield of Safflower (Carthamus tinctorius L.) in Central Italy

Safflower is a multipurpose crop with several uses that can offer benefits to rainfed cereal-based cropping systems due to its tolerance to cold, drought, salinity, and its reduced need for agricultural inputs. Safflower requires good weed control for optimum yields because it is a very poor competitor with weeds, especially at the early growth stage, but registered pre-emergence herbicides are not available. This research investigated the effects of several pre-emergence herbicides on weed control and the yield of safflower in central Italy, through two field experiments in 2019 and 2020. Aclonifen, metazachlor, s-metolachlor, propyzamide, and metribuzin were applied as pre-emergence herbicides. The main weeds were the following: Papaver rhoeas L., Conyza canadensis (L.) Cronq., and Ammi majus L. in experiment 1, and wild sunflower (Helianthus annuus L.) in experiment 2. Metazachlor and metribuzin gave the highest phytotoxicity on safflower in both experiments, with values ranging from 48% to 75% and from 30% to 75% (in a scale of 0–100%), respectively, and seem to be not advisable as pre-emergence herbicides. Aclonifen, s-metolachlor, and propyzamide can be considered selective and safe to the safflower, showing the lowest values of phytotoxicity that ranged from 0 to 10%. Metazachlor and s-metolachlor gave the highest total weed control with values of 92% and 97%, respectively.

Development and characterization of a new sunflower source of resistance to race G of Orobanche cumana Wallr. derived from Helianthus anomalus

Key messageA new OrAnom1 gene introgressed in cultivated sunflower from wild Helianthus anomalusconfers late post-attachment resistance toOrobanche cumana race G and maps to a target interval in Chromosome 4 where two receptor-like kinases (RLKs) have been identified in theH. anomalusgenome as putative candidates.Sunflower broomrape is a parasitic weed that infects sunflower (Helianthus annuus L.) roots causing severe yield losses. Breeding for resistance is the most effective and sustainable control method. In this study, we report the identification, introgression, and genetic and physiological characterization of a new sunflower source of resistance to race G of broomrape developed from the wild annual sunflower H. anomalus (accession PI 468642). Crosses between PI 468642 and the susceptible line P21 were carried out, and the genetic study was conducted in BC1F1, BC1F2, and its derived BC1F3 populations. A BC1F5 germplasm named ANOM1 was developed through selection for race G resistance and resemblance to cultivated sunflower. The resistant trait showed monogenic and dominant inheritance. The gene, named OrAnom1, was mapped to Chromosome 4 within a 1.2 cM interval and co-segregated with 7 SNP markers. This interval corresponds to a 1.32 Mb region in the sunflower reference genome, housing a cluster of receptor-like kinase and receptor-like protein (RLK-RLP) genes. Notably, the analysis of the H. anomalus genome revealed the absence of RLPs in the OrAnom1 target region but featured two RLKs as possible OrAnom1 candidates. Rhizotron and histological studies showed that OrAnom1 determines a late post-attachment resistance mechanism. Broomrape can establish a vascular connection with the host, but parasite growth is stopped before tubercle development, showing phenolic compounds accumulation and tubercle necrosis. ANOM1 will contribute to broadening the genetic basis of broomrape resistance in the cultivated sunflower pool and to a better understanding of the molecular basis of the sunflower-broomrape interaction.

Chemical Analysis of Kitchen Waste for Developing Formulae for Compost Fertilizer

The rapid growth of the global population and changes in food consumption patterns have resulted in issues relating to food insecurity. Improved strategic solutions are needed to allow easy access to food and also to manage large volumes of waste efficiently. From this research, a microeconomic- level solution to manage the aforementioned issues is addressed. Common kitchen waste such as peels and discarded parts of fruits and vegetables can be combined to produce compost fertilizer. Producing compost fertilizer in this manner can be considered a microeconomic-level waste management strategy. Compost fertilizer produced using kitchen waste can subsequently be used in home gardening. Many vegetables and fruits can easily be cultivated in small, confined spaces such as in home gardens. This study analyzed chemical parameters such as total carbon and other total nutrient levels (N, P, Ca, Mg and K) in ten kitchen waste and two supplementary samples using standard methods. The kitchen waste samples consisted of peels and discarded parts of fruits and vegetables. The two supplementary samples- Tithonia diversifolia (Wild sunflower), and Gliricidia sepium were chosen because they are nutrient-rich organic fertilizers. The analysis results were then fed to a computer program developed for this study. It was based on the simulated annealing algorithm. The program generated different formulae for producing 100 g mixtures of raw materials for composting, by mixing the 10 kitchen waste and 2 supplementary samples in 24 different combinations. The nutrient levels of these mixtures were expected to match or exceed a calculated ―target nutrient level‖. It was calculated based on local compost fertilizer standards and the chemical analysis results. The target nutrient level calculated as the minimum required level by dry mass of each material was 25.00% Carbon, 1.25% Nitrogen, 0.63% Phosphorus, 1.25% Potassium, 0.88% Calcium, and 0.63% Magnesium. The program was able to generate mixtures of raw materials in which most of the levels matched or exceeded the target level. However, the phosphorus levels of all formulae fell below the target phosphorus level and in some mixtures, the magnesium level also was less than the targeted level. The actual nutrient level of one of the 100 g mixtures (combination C3) containing 0.19 g banana stem, 0.21 g discarded tea grounds, 0.41 g discarded scraped coconut, 0.57 g banana peel, and 97.34 g Gliricidia leaves was (% by dry mass), 85.68% Carbon, 2.20% Nitrogen, 0.25% Phosphorus, 1.32% Potassium, 2.24% Calcium and 0.71% Magnesium. This promising method can further be developed by adding more nutrient-rich raw materials to the program. The program could be a useful tool for compost fertilizer manufacturing, especially for small-scale horticultural purposes. 
 Keywords: Compost, Waste management, Nutrient analysis, Kitchen waste

Allelopathic Potential of Aqueous Extracts of Wild Sunflower (Tithonia diversifolia (Hemsl.) A. Gray) and Sorghum (Sorghum bicolor (L.) Moench) for Controling Weeds and Enhancing Yield of Cowpea (Vigna unguiculata (L.) Walp)

Cowpea is an important grain legume in Sri Lanka. Approximately 53–60% of yield losses in cowpea cultivation are attributed to weeds. Chemical weed control (herbicide), is one of the method in weed control in cowpea. Import of herbicide have been prohibited recently since of government policy and the nation's economic problems. As a result, it's critical to identify other suitable alternatives. In this context, a field experiment was conducted to study the effect of aqueous extract of wild sunflower and sorghum on weed control, growth and yield of cowpea. The experiment consisting of five weed control treatments viz T1 (aqueous extract of wild sunflower; 12 L ha-1 ,T2 (aqueous extract of sorghum; 12 L ha-1), T3 (combined application of both wild sunflower and sorghum aqueous extract in a 1:1 ratio; 6+6 L ha-1), T4 (hand weeding), and T5 (unweeded check-control) was conducted in Randomized Complete Block Design with four replication in the crop farm of Eastern University, Sri Lanka.. The experiment was conducted from September to November 2022. Hand weeding was done on 21 and 42 DAS while application of aqueous extracts were done on 2, 21, and 35 DAS. Minitab 17 software was used for the statistical analysis, and Tukey's test was used to compare the treatment means. The results revealed that the different weed control treatments had a substantial (P<0.05) impact on weed population & dry weight, growth and yield of cowpea. When compared to the control, hand weeding was found to be most effective to control weeds followed by combined application of aqueous extracts from wild sunflower and sorghum Hand weeding and the combined application of aqueous extracts significantly reduced the number of weeds by 82.98 and 54.39%, respectively. Further, the hand weeding and combined application of extract significantly enhanced yield by 45.09% and 62.85% respectively in comparison to the control (unweeded check). According to the study's findings, it can be concluded that under the condition of Sri Lanka, combined application of aqueous extracts was proved to be more remunerative and sustainable alternate option for weed control in cowpea crop.

Secretory Tissues and Volatile Components of Disc Florets in Several Wild Helianthus L. Species

Although flower pollinator interactions are known to be mediated by floral traits, not enough attention has been paid to the research of secretory tissues and volatile components of sunflower disc florets as potentially important parameters in breeding programs. (1) To our knowledge, this is the first integrated study aimed at better understanding the attractiveness of sunflower capitula to insects. In the study, we have made a very detailed comparative analysis of secretory tissues and the characterization of the volatile components (VOCs) of disc florets in 10 wild perennial Helianthus species. (2) For anatomical analyses, cross-sections were obtained from the nectary zone of disc florets using a cryotechnique procedure. Micromorphological observation and morphological and anatomical analysis of disc florets were performed using light and scanning electron microscopy. For VOCs, we applied headspace, GC-FID, and GC/MS analyses. (3) The obtained results indicate that there is a difference between the analyzed traits among studied species. H. eggertii, H. hirsutus, H. mollis, H. resinosus, and H. tuberosus had high disc diameter values, a high cross-section area and disc floret corolla length, as well as the largest cross-section area and thickness of the disc florets nectary. In the analyzed VOCs, 30 different compounds were detected. The highest yield and quantity of α-Pinene was observed in H. mollis. (4) Inflorescence features, such as receptacle diameter, corolla and secretory tissue properties, and floret VOCs production and characterization, provided valuable information that can be used as guidelines in sunflower breeding programs to maximize pollinator attractiveness and increase seed yield.

Weeds and ruderal plants as potential sources of inoculum for vegetable diseases in northern Sinaloa

Weeds and ruderal plants of the families Cucurbitaceae and Solanaceae are addressed as potential sources of inoculum for the development of viral diseases such as Tomato apex necrosis virus (ToANV), zucchini (Zucchini yellow mosaic virus (ZYMV), Watermelon mosaic virus (WMV), Papaya ring spot virus (PRSV-W) and Cucumber mosaic virus (CMV). Reference is made to weeds and ruderal plants as potential sources of inoculum, including wild sunflower for powdery mildew (Golovinomyces spadiceus), wild tobacco for foliar blight (Alternaria spp.), black nightshade for leaf spot (Curvularia moehlemvekiae), Johnson grass for foliar blight (Alternaria sp.), and wild castor bean for foliar blight (Alternaria ricini) and wild melon for downy mildew (Pseudoperonospora cubensis). Future lines of multidisciplinary research focusing on the determination of pathogenicity in cultivated plants of viruses and fungi associated with wild plants and vice versa are proposed; the spatial-temporal distribution of wild plants that may serve as sources of inoculum, as well as the of potential insect vectors of viral diseases, should also be studied. The implementation of modern molecular techniques, such as High Throughput Sequencing, for the detection of phytopathogens is important. All this will contribute to the implementation of environmentally friendly strategies for disease control in agricultural crops in Sinaloa, for the benefit of the vegetable growers.

Tek Yıllık Yabani Ayçiçeği Türlerinin Tarla Koşullarında Bazı Morfolojik, Fenolojik ve Agronomik Karakterleri Açısından Değerlendirilmesi

New gene sources are needed for adaptation to climatic changes, resistance to the regeneration of diseases and pests, and achieving high heterosis in sunflower breeding. Wild species are the most important gene sources for sunflower breeding studies. For breeding studies, it is necessary to know the morphological, Phenological, and agronomic characteristics of these genotypes in field conditions. The aim of this research was to determine these components of annual wild sunflower (Helianthus) species under field conditions in the 2012 and 2013 growing seasons for new gene sources. In this research, H. agrestis, H. annuus (4 different genotypes), H. anomalus, H. argophyllus, H. bolanderi, H. debilis (ssp. debilis, ssp. cucumerifolius, ssp. silvestris, ssp. tardiflorus and ssp. vestitus subspecies), H. deserticola, H. exilis, H. neglectus, H. niveus (ssp. niveus, ssp. canescens and ssp. tephrodes subspecies) H. petiolaris (ssp. petiolaris (2 different genotypes) and ssp. fallax subspecies), H. porteri, and H. praecox (ssp. praecox (2 different genotypes), ssp. hirtus, and ssp. runyani subspecies) were used as material. In this study, determined characters on annual wild sunflower genotypes were plant height, primary branches number, secondary branches number per primary branches, plant spreading diameter, the number of days from planting to first flowering, the number of days from planting to 50 % flowering, the number of days from planting to the end of flowering, the number of days of the flowering period, main stem diameter, head diameter, 1000 seeds weight, and seed yield. Year factor had a significant effect on these characters except plant height. Genotype had a significant effect on all characters in both years except seed width in 2013. In both years, the highest values for seed yield, 100 seed weight, head diameter, and main stem diameter were obtained in wild H. annuus genotypes while H. argophyllus had the highest values for plant height and primary branches number, and the highest days numbers from planting to first and 50% flowering. In the first and second growing seasons; values of the genotypes changed between 61.33 and 325.67 cm for plant height, between 0.73 and 101.20 g for thousand seed weight, between 97 and 223 days for the time from planting to 50% flowering, between 50 and 171 days for the flowering period, between 5.0 and 800.70 units for the number of plant heads, between 1.57 and 233.20 g for plant grain yields.

Prebreeding and genetic enhancement of cultivated sunflower (Helianthus annuusL.) using diploid wild Helianthus species in India

Pre-breeding activities using promising diploid wild Helianthus like Helianthus annuus (wild), H. argophyllus, H. praecox, H. debilis and H. petiolaris and popular cultivar (ARM-243B) have been initiated at ICAR Indian Institute of Oilseeds Research, Rajendranagar, Hyderabad to increase the frequency of desirable genes, wider adaptability and a broad genetic base. Wider variability was observed for yield and yield contributing traits besides disease reactions within and between species. Evaluation of a few populations for biotic stresses and yield related traits resulted in the identification of desirable introgression lines. The highest seed yield (42.5 g/plant) was reported in combinations with H. annuus (wild), H. petiolaris (40.2 g/plant) and H. debilis (39.8 g/plant). Interspecificderivatives derived from H. praecox were found resistant to powdery mildew. Interspecific derivatives of H. argophyllus, namely PB-1001, PB-1003, PB-1005, PB-1007, PB-1008, PB-1014, and PB-1019 were resistant to leafhoppers, while PB-1003, PB-1005, and PB-1007 exhibited resistant reactions to downy mildew under sick plot conditions. H. debilis derivatives viz., PB-120, PB-127, PB-128, PB-129 and PB-130 recorded >40% oil content. The pre-breeding lines derived from these interspecific cross combinations serve as an invaluable reservoir of genes for carrying out basic studies on the key traits as well as the exploitation of agronomically desirable traits in the AICRP sunflower breeding programmes.

Effects of NPK Fertilizer application and plant density on forage yield and chemical composition of wild sunflower (Tithonia diversifolia)

A study was conducted in 2017 and 2018, in the Forest Zone of southwestern Nigeria, to evaluate the yield and chemical composition of wild sunflower (Tithonia diversifolia) fertilized with compound fertilizer (20N:10P2O5:10K2O), under different planting densities. Seedlings of 20-day old Tithonia diversifolia were transplanted on a site, in a split plot arrangement, with fertilizer application at 0, 50, 100, 200 and 400kg/ha, using a planting density of 83.3 ×103, 166.7 ×103, 222 ×103, 333 ×103, 500 ×103, and 1000 ×103 plants/ha. After 114-116 days of growth, the plants were harvested and analyzed for proximate composition. The highest whole plant DM yield occurred at 400 kg/ha fertilizer level and a population density of 333×103 plants/ha. Leaf and inflorescence DM yields peaked at 400 kg/ha fertilizer application while the best leaf yield and inflorescence response to density resulted from 333 ×103 plants/ha, regardless of year under investigation. Overall fertilizer treatments and across densities, the leaf and inflorescence fractions recorded 16.88-22.92 % and 14.38-15.10% CP, 12.09-13.24 % and 21.25-23.60 % CF, 4.89-5.60 % and 3.67-4.72 % EE and 13.42-14.84 % and 6.27-7.53 % ash, respectively. Results obtained suggest that the high biomass yield of Tithonia diversifolia combined with its satisfactory nutrient levels, qualifies the plant as a potential suitable feed supplement source for ruminant livestock.
 
 
 
 
 Une étude a été menée en 2017 et 2018, dans la zone forestière du sud-ouest du Nigéria, pour évaluer le rendement et la composition chimique du tournesol sauvage (Tithonia diversifolia) fertilisé avec un engrais composé (20N:10P2O5:10K2O), sous différentes densités de plantation. Des semis de Tithonia diversifolia âgés de 20 jours ont été transplantés sur un site, dans une disposition en parcelles divisées, avec une application d'engrais à 0, 50, 100, 200 et 400 kg/ha, en utilisant une densité de plantation de 83,3 × 103, 166,7 × 103, 222. ×103, 333 ×103, 500 ×103 et 1 000 ×103 plants/ha. Après 114 à 116 jours de croissance, les plantes ont été récoltées et analysées pour déterminer leur composition immédiate. Le rendement le plus élevé en matière sèche de plante entière a été obtenu avec un niveau d'engrais de 400 kg/ha et une densité de population de 333 × 103 plantes/ha. Les rendements en matière sèche des feuilles et des inflorescences ont culminé à 400 kg/ha d'application d'engrais, tandis que le meilleur rendement foliaire et la meilleure réponse de l'inflorescence à la densité résultaient de 333 × 103 plantes/ha,quelle que soit l'année étudiée. Dans l'ensemble des traitements d'engrais et selon les densités, les fractions de feuilles et d'inflorescences ont enregistré 16,88-22,92 % et 14,38-15,10 % CP, 12,09 13,24 % et 21,25-23,60 % CF, 4,89-5,60 % et 3,67-4,72 % EE et 13,42-14,84 %. et 6,27 à 7,53 % de cendres, respectivement. Les résultats obtenus suggèrent que le rendement élevé en biomasse de Tithonia diversifolia, combiné à ses niveaux de nutriments satisfaisants, qualifie la plante comme une source potentielle de complément alimentaire appropriée pour le bétail des ruminants.

Bioprospecting for improved floral fragrance in wild sunflowers

Abstract Cultivated sunflower (Helianthus annuus) is not typically considered to have a pleasant floral fragrance. In field production, seed yield is often limited by pollination services, particularly in the production of hybrid seed. Improved floral fragrance, as determined by volatile organic compounds, may be a route to improving pollinator attraction for oilseed and confectionary production and could also add value to ornamental sunflowers. Wild relatives of H. annuus have a long history of being used to breed improved traits into cultivated varieties, yet it is unknown whether favorable scents are present in wild Helianthus species and thus an available resource for fragrance breeding. In order to assess the diversity of floral fragrance available in crop wild relatives, 30 diverse accessions of wild Helianthus as well as seven varieties of H. annuus spanning a domestication gradient were grown in greenhouse experiments and variation in floral volatiles was analyzed by solid phase microextraction-gas chromatography-mass spectrometry. While alpha-pinene made up a significant portion of the volatiles emitted for most taxa, there was substantial diversity present across the genus as well as within H. annuus. Most volatiles emitted were monoterpenoids with a significant share of sesquiterpenoids. The diversity identified here will inform further targeted study of which compounds affect pollinator attraction and health. Several wild accessions such as Helianthus debilis subsp. tardiflorus and Helianthus praecox subsp. praecox as well as open-pollinated domesticated accessions of H. annuus show promise for breeding for improved floral fragrance due to high volatile abundance and likely favorable compound compositions.

Genetic analysis of basal stalk rot resistance introgressed from wild Helianthus petiolaris into cultivated sunflower (Helianthus annuus L.) using an advanced backcross population.

Sclerotinia sclerotiorum is a serious pathogen causing severe basal stalk rot (BSR) disease on cultivated sunflower (Helianthus annuus L.) that leads to significant yield losses due to insufficient resistance. The wild annual sunflower species H. petiolaris, commonly known as prairie sunflower is known for its resistance against this pathogen. Sunflower resistance to BSR is quantitative and determined by many genes with small effects on the resistance phenotype. The objective of this study was to identify loci governing BSR resistance derived from H. petiolaris using a quantitative trait loci (QTL) mapping approach. BSR resistance among lines of an advanced backcross population (AB-QTL) with 174 lines developed from a cross of inbred line HA 89 with H. petiolaris PI 435843 was determined in the field during 2017-2019, and in the greenhouse in 2019. AB-QTL lines and the HA 89 parent were genotyped using genotyping-by-sequencing and a genetic linkage map was developed spanning 997.51 cM and using 1,150 SNP markers mapped on 17 sunflower chromosomes. Highly significant differences (p<0.001) for BSR response among AB-QTL lines were observed disease incidence (DI) in all field seasons, as well as disease rating (DR) and area under the disease progress curve (AUDPC) in the greenhouse with a moderately high broad-sense heritability (H 2) of 0.61 for the tested resistance parameters. A total of 14 QTL associated with BSR resistance were identified on nine chromosomes, each explaining a proportion of the phenotypic variation ranging from 3.5% to 28.1%. Of the 14 QTL, eight were detected for BSR resistance in the field and six were detected under greenhouse conditions. Alleles conferring increased BSR resistance were contributed by the H. petiolaris parent at 11 of the 14 QTL.

Molluscicidal properties of wild sunflower (Tithonia diversifolia) leaf extract fractions against invasive golden apple snail (Pomacea canaliculata)

Molluscicidal properties of wild sunflower (Tithonia diversifolia) leaf extract fractions against invasive golden apple snail (Pomacea canaliculata)

Registration of HA‐DM15 and HA‐DM16 oilseed sunflower germplasms with resistance to sunflower downy mildew

AbstractSunflower (Helianthus L.) production ranked third in global oilseed production in 2021. Downy mildew (DM), caused by the oomycete pathogen Plasmopara halstedii (Farl.) Berl. et de Toni, is a major constraint for worldwide sunflower production, causing significant yield losses in susceptible hybrids. The search for new sources of resistance to DM is the primary objective of all sunflower breeding programs. Germplasms HA‐DM15 (Reg. no. GP‐385, PI 702359) and HA‐DM16 (Reg. no. GP‐386, PI 702360) were developed by introgressing two new DM resistance genes, Pl37 and Pl38, from the wild sunflower species H. annuus and H. praecox into oilseed sunflower, respectively. The BC1F3‐derived HA‐DM15 harboring the Pl37 gene was selected from the cross of HA 89//NMS HA 89/wild H. annuus PI 435417. The germplasm line HA‐DM16 carrying the Pl38 gene is an improved oilseed derivative of Rf PRA‐417 with DM resistance originally derived from the wild H. praecox PRA‐417 from the cross of cytoplasmic male sterile (CMS) HA89*2/wild H. praecox PRA‐417. HA‐DM15/Pl37 and HA‐DM16/Pl38 are immue to the most predominant and virulent DM races idenfied in North America and Europe. Pl37 and Pl38 have been genetically mapped to sunflower chromosomes 4 and 2, respectively, with single nucleotide polymorphism markers linked to the both genes facilitating their transfer to elite sunflower lines by marker‐assisted selection, providing new and diverse sources for sunflower DM‐resistance breeding.

Callus Induction And Antibacterial Activity Of Verbesina Encelioides Leaves

Verbesina encelioides belongs to the Asteraceae family and also known as golden crown beard and wild sunflower. In present study callus was raised from the leaf explant of V. encelioides. Callus was obtained on MS medium formed using 3% sucrose and 0.8% agar incorporated with 2mg/L BAP and 0.5 mg/L IAA. The callus was used for antibacterial activity identification. The results indicated Callus was brownish yellow in color and compact. E. coli and B. subtilis which showed almost similar activities. B. subtilis was most responsive in methanol extract (14mm), E. coli was inhibited best by ethyl acetate. This study proves that V. encelioides callus extracts were more prominent and showed much efficient activity in comparison to that of leaf extract.

Origin of CMS-PET1 cytotype in cultivated sunflower: A new insight

The vast majority of commercial sunflower hybrids worldwide are produced using cytoplasmic male sterility (CMS) of the PET1 type, resulting from the interspecific hybridization of Helianthus petiolaris with Helianthus annuus. Due to the fact that CMS-PET1 was not previously detected in wild sunflower, it was believed that this cytotype could arise during interspecific hybridization and is specific solely for cultivated sunflower. In this study, the open reading frame, orfH522, associated with the CMS-PET1 phenotype, was revealed for the first time in the 3′-flanking region of the mitochondrial atpA gene in wild H. annuus. An analysis of whole genome data from 1089 accessions showed that the frequency of occurrence of CMS-orfH522 in wild H. annuus populations is 3.58%, while in wild H. petiolaris populations, it is 1.26%. In general, the analysis demonstrated that PET1-CMS is a natural cytotype of H. annuus, and the appearance of the CMS phenotype in cultivated sunflowers is associated with the loss of stabilizing nuclear genes of fertility restorers, which occurred during interspecific hybridization. These data can explain the patterns of differential cytoplasmic and nuclear introgression occurring in wild sunflower and are useful for further evolutionary studies.