Sunflower Lines Research Articles

The inheritance pattern for the dwarf phenotype in hybrids from crosses among sunflower lines differing in alleles of the Rht1 locus

Background. Sunflower seed production is based on utilization of the heterosis effect, manifesting itself in improving both yield and plant height in hybrids. Short-stemmed lines need to be used to develop commercial hybrids with an optimum height. Molecular bases of the trait manifestation in the dwarf lines from VIR’s sunflower genetic collection have not yet been studied. Materials and methods. The material included 27 short-stemmed and 10 tall sunflower lines from VIR’s genetic collection, as well as the F1 and F2 hybrid generations derived from crossing the tall (VIR 340) and dwarf (VIR 171) genotypes. The parental lines and hybrids were phenotyped for plant height, leaf number, and internode length. Genotyping for the Rht1 locus (HaDella1 candidate gene), encoding the negative regulator of the gibberellin response, the DELLA protein, was performed using the developed CAPS marker. Results. The average plant height in the VIR 340 line over a three-year study was 162 cm, the number of leaves 29, and the internode length 6 cm. The VIR 171 line demonstrated the plant height of 66 cm, leaf number of 24, and internode length of 2.8 cm. The F1 hybrids were uniform, with the height of 180–190 cm, that indicated the dominance of the long stem trait. Analyzing the segregation in the F2 hybrid generation led to an assumption admitting the digenic control of the dwarf phenotype in the VIR 171 line. The CAPS marker G-D-1/ Bmt I was developed to identify a missense mutation T>C in the first exon of the HaDella1 gene, which results in the substitution of leucine with proline in the DELLA motif. Using the marker, the mutant Rht1 allele was identified in the VIR 171 and VIR 434 dwarf lines, similar in their origin and phenotype. The results of validation in the F2 hybrid population (VIR 340 × VIR 171) confirmed the efficiency of the G-D-1 / Bmt I marker for selecting dwarf genotypes homozygous for the Rht1 mutant allele.

Identification of Autogamous and Self-Fertile Lines in Sunflower (Helianthus annuus L.) Over Seasons

This study aims to assess the autogamy and self-fertility percentage in sunflower (Helianthus annuus L.) across two distinct cropping seasons. Sunflower possesses self-incompatibility which can be overcome by exploring alternate pollination methods. Autogamy and self-fertility are two desirable traits of sunflowers that play an important role in reproductive success and yield stability. Through the examination of 46 genotypes, the research aims to determine the effects of seasonal variations on seed set, autogamy, and self-fertility across different sunflower genotypes during the Kharif and Rabi seasons. The study compared three modes of pollination: self-pollination (SP), self-pollination plus manual (S+M) pollination, and open pollination (OP). Results indicated that the Rabi season favoured a higher seed set and better seed filling compared to the Kharif season. The study revealed that the Rabi season’s cooler temperatures, higher humidity, and reduced solar radiation positively influenced seed yield and quality. In contrast, Kharif season conditions, particularly the monsoon, led to reduced seed yield and fewer filled seeds due to factors like higher pollen movement and lower humidity inside pollination bags. The autogamy and self-fertility percentages during Rabi were higher at 79.01 percent and 85.01 percent, respectively. Genotypes PB-892, EC-198072, and PB-1444 showed the highest seed set under S+M pollination during Kharif, while CMS-107B, PB-1212, and CMS-47B excelled in SP. Across both seasons, EC-198078, EC-178168, and GMU-770 were identified as highly self-fertile, making them valuable for developing self-fertile hybrids and enhancing population development.

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.

Multi-scale characterisation of cold response reveals immediate and long-term impacts on cell physiology up to seed composition in sunflower.

Early sowing can help summer crops escape drought and can mitigate the impacts of climate change on them. However, it exposes them to cold stress during initial developmental stages, which has both immediate and long-term effects on development and physiology. To understand how early night-chilling stress impacts plant development and yield, we studied the reference sunflower line XRQ under controlled, semi-controlled and field conditions. We performed high-throughput imaging of the whole plant parts and obtained physiological and transcriptomic data from leaves, hypocotyls and roots. We observed morphological reductions in early stages under field and controlled conditions, with a decrease in root development, an increase in reactive oxygen species content in leaves and changes in lipid composition in hypocotyls. A long-term increase in leaf chlorophyll suggests a stress memory mechanism that was supported by transcriptomic induction of histone coding genes. We highlighted DEGs related to cold acclimation such as chaperone, heat shock and late embryogenesis abundant proteins. We identified genes in hypocotyls involved in lipid, cutin, suberin and phenylalanine ammonia lyase biosynthesis and ROS scavenging. This comprehensive study describes new phenotyping methods and candidate genes to understand phenotypic plasticity better in response to chilling and study stress memory in sunflower.

Multiple Forms of Resistance to the Phomopsis Stem Canker Pathogens Diaporthe helianthi and D. gulyae in Sunflower.

Phomopsis stem canker of cultivated sunflower (Helianthus annuus L.) can be caused by multiple necrotrophic fungi in the genus Diaporthe, with Diaporthe helianthi and D. gulyae being the most common causal agents in the United States. Infection begins at the leaf margins and proceeds primarily through the vasculature, progressing from the leaf through the petiole to the stem, resulting in formation of brown stem lesions centered around the petiole. Sunflower resistance to Phomopsis stem canker is quantitative and genetically complex. Due to the intricate disease process, resistance is possible at different stages of infection, and multiple forms of defense may contribute to the overall level of quantitative resistance. In this study, sunflower lines exhibiting field resistance to Phomopsis stem canker were evaluated for stem and leaf resistance to multiple isolates of D. helianthi and D. gulyae in greenhouse experiments, and responses to the two species were compared. Additionally, selected resistant and susceptible lines were evaluated for petiole transmission resistance to D. helianthi. Lines with distinct forms of resistance were identified, and results indicated that responses to stem inoculation were strongly correlated (Spearman's coefficient 0.598, P < 0.001) for the two fungal species, while leaf responses were not (Spearman's coefficient 0.396, P = 0.076). These results provide a basis for genetic dissection of distinct forms of sunflower resistance to Phomopsis stem canker and will facilitate combining different forms of resistance to potentially achieve durable control of this disease in sunflower hybrids.

Genome-wide identification and in-silico expression analysis of CCO gene family in sunflower (Helianthus annnus) against abiotic stress

Carotenoid cleavage oxygenases (CCOs) enzymes play an important role in plant growth and development by producing a wide array of apocarotenoids and their derivatives. These compounds are vital for colouring flowers and fruits and synthesizing plant hormones such as abscisic acid and strigolactones. Despite their importance, the gene family responsible for CCO enzymes in sunflowers has not been identified. In this study, we identify the CCO genes of the sunflower plant to fill this knowledge gap. Phylogenetic and synteny analysis indicated that the Helianthus annnus CCO (HaCCO) genes were conserved in different plant species and they could be divided into three subgroups based on their conserved domains. Analysis using MEME tool and multiple sequence alignment identified conserved motifs in the HaCCO gene sequence. Cis-regulatory elements (CREs) analysis of the HaCCO genes indicated the presence of various responsive elements related to plant hormones, development, and responses to both biotic and abiotic stresses. This implies that these genes may respond to plant hormones, developmental cues, and drought stress, offering potential applications in the development of more resistant crops. Genes belonging to the 9-cis-epoxy carotenoid dioxygenases (NCED) subgroups predominantly exhibited chloroplast localization, whereas the genes found in other groups are primarily localized in the cytoplasm. These 21 identified HaCCOs were regulated by 60 miRNAs, indicating the crucial role of microRNAs in gene regulation in sunflowers. Gene expression analysis under drought stress revealed significant up-regulation of HaNCED16 and HaNCED19, genes that are pivotal in ABA hormone biosynthesis. During organ-specific gene expression analysis, HaCCD12 and HaCCD20 genes exhibit higher activity in leaves, indicating a potential role in leaf pigmentation. This study provides a foundation for future research on the regulation and functions of the CCO gene family in sunflower and beyond. There is potential for developing molecular markers that could be employed in breeding programs to create new sunflower lines resistant to biotic and abiotic stresses.

Rapid Restructuring of Rhizosphere and Endospheric Fungal Communities with Drought in Multiple Lines of Domesticated Sunflower

Plant-associated mycobiomes can influence important host plant traits including those related to disease, nutrient acquisition, flowering phenology, stress tolerance, and productivity. Disentangling the complex multifaceted relationships between host plants and their associated mycobiomes is a critical first step toward generating improvements in environmental sustainability and/or plant productivity. Despite decades of work on these plant–fungal interactions, consequences of and mechanisms controlling these interactions are not well resolved, especially in the face of environmental stress such as drought. Moreover, plant differential genotypic responses under stress and associated mycobiome assembly dynamics are likely important in structuring communities but have been less well studied. We conducted a controlled drought stress experiment by manipulating water treatment in a diverse set of cultivated sunflower lines with different inherent drought resistance levels to evaluate how sunflower host genotypes and drought interacts to affect belowground fungal mycobiomes at the rhizospheric and endospheric levels. Our results demonstrated that fungal community structure was driven by watering treatment, plant genotype, treatment by genotype interactions, genotype by plant compartment interactions, and treatment by genotype by compartment interactions. Additionally, our analyses demonstrated the relative abundance of plant pathogens and arbuscular mycorrhizal fungi increased with host genetic variation, or heterozygosity, levels. Our study provides evidence for drought and genotypic drivers of belowground sunflower–fungi interactions and offers a framework for leveraging these interactions to further understand how mycobiome community structure can improve plant productivity under stress.

Comparative profile of transcripts from anthers of hybrid plants and parental lines of sunflower

Most heterosis research over the years has focused on increasing vigour and productivity, and less on the multitude of biochemical and molecular phenotypes as an expression of hybrid superiority under favourable or stressful conditions. Plant productivity depends on the microsporogenesis and microgametogenesis processes highly sensitive to unfavorable environmental conditions and other stress factors that often induce the androsterility. The paper presents the results of the expression polymorphism analysis (by RT-qPCR) of candidate genes with functions in DNA replication, recombination, repair, and mitochondrial morpho-functional organization processes in anthers of homozygous and heterozygous sunflower plants with phenotypic differences in male gametophyte (fertile/sterile). A particular interest in this research represented the identification of gene expression patterns in hybrid (F1) plants in norm, for possible associations of transcriptional response with heterozygous effect, and under conditions of induced stress (gibberellin treatment) as a factor in irreversible phenotype change of anthers from fertile to sterile. Thus, the high proportion of different non-additive and transgressive expression patterns in hybrid plants was established, revealing genetic divergence and expression polymorphisms in parental lines. The sterile anther phenotype of hybrid plants obtained by gibberellin treatment of the inflorescence at the buttoning phase is causally related to changes in allelic gene expression patterns at different phases of microsporogenesis.

Multivariate analysis among indigenous and exotic advanced inbred lines of sunflower (Helianthus annuus L.) for genetic improvement

Evaluation and validation of 358 Indian-origin and exotic inbred lines of sunflower (Helianthus annuus L.) was done over two years toidentify trait-specific inbreds with desirable agronomical features for genetic improvement. The analysis of variance exhibited significant differences among the genotypes for most of the agronomic traits studied, which favor selection. Positive correlations were recorded among the various characters in the improvement of seed yield, particularly for plant height, head diameter, and 100 seed weight. Cluster analysis grouped 163 inbreds under Cluster V, which included genotypes with medium maturity, high oil content and good yielding ability. The clustering pattern indicated the association between geographic diversity and genetic diversity. The first principal component accounted for 75% of the total variation in the population. The most important trait that contributed more to the variation in PC1 was plant height (0.989), followed by the number of leaves per plant (0.113). The second principal component accounted for 87% of the total variation and was positively associated with days to 50% flowering (0.674) and days to maturity (0.654), whereas it was negatively associated with seed yield per plant (-0312). Several trait-specific inbred lines were identified using multivariate analysis that may serve as potential breeding material/parental lines for effective utilization in the heterosis breeding programme for developing agronomically superior heterotic sunflower hybrids.

Challenges in sunflower breeding for cold tolerance

Introduction. Sunflower is grown as an oilseed crop worldwide. For sunflower production, it is vital to have cold-tolerant hybrids. An appropriate method to assess cold tolerance is a prerequisite for successful breeding of cold-tolerant sunflower.&#x0D; Purpose and Objectives. To evaluate cold tolerance of sunflower in the laboratory and its tolerance in the field, to identify promising combinations, to assess the capacity of a laboratory test to predict tolerance of sunflower in the field and to verify relationships of cold tolerance with ripeness group and yield.&#x0D; Materials and Methods. Sunflower was grown in compliance with standard farming techniques. In total, 192 F1 hybrids were obtained. The lines and hybrids were screened for ability to germinate at above-zero low temperature by laboratory test. The field tolerance at the initial stages of plant growth was determined with a 9-point scale. Relationships between the investigated parameters were analyzed by linear regression.&#x0D; Results and Discussion. The highest field tolerance at the initial stages of plant growth was recorded for Kh4713V, Skh777А and Skh808А lines. However, they only conferred tolerance to some of their hybrids. On the other hand, several hybrids were fairly tolerant in the field though the tolerance scores of their parental lines ranged 1 to 5 points. There was no relationship between the ‘emergence – anthesis’ period and cold tolerance. A great degree of uncertainty is associated with predicting field tolerance of sunflower from its cold tolerance assessed by laboratory test. This laboratory test cannot be used to predict field tolerance of either lines or hybrids. There was a strong positive correlation between the field tolerance and seed yield in the lines, but the correlation coefficient for the hybrids indicated no significant correlation between these parameters.&#x0D; Conclusions. At non-freezing low temperatures, the yield of the inbred sunflower lines was positively correlated with the field tolerance score at the early stages of plant growth and development. There was no significant difference in responses of early- and medium-ripening sunflower genotypes to cold exposure. Lakhanov’s cold germination test is not appropriate for evaluation of field tolerance in sunflower lines and hybrids.

Identification of restorer lines for diversified CMS lines in Sunflower (Helianthus annuus L.)

The material for the study consisted of three stable CMS lines viz., CMS 103A, CMS104A, and CMS 38A as female lines and 50 new inbred lines as testers. All the three CMS lines and 50 inbred lines were crossed in a Line × Tester fashion and resultant 150 hybrids were evaluated for fertility restoration. Among common restorers across all three CMS lines, RCR-20-8 recorded highest gca for seed yield, oil content and plant height, followed by RCR20-19 for head diameter and seed yield; RCR-20-13 for volume weight and early flowering. These lines can be used as testers for developing hybrids and also for development of new tester lines with combination of desirable characters.

Characterization of sunflower (Helianthus Annuus L.) lines for Alternariaster leaf spot disease resistance

Leaf spot disease is an important disease of sunflower that reduces the photosynthetic area and causes the yield loss. An investigation was undertaken for screening of breeding lines to Alternariaster leaf spot during Kharif 2021. Among 75 breeding lines including susceptible check KBSH-44 evaluated in augmented block design with two replications at Sunflower Scheme, MARS, Raichur, five lines viz., RSLP-18 (PDI=8), RSLP-22(PDI=8), RSLP98(PDI=7.5), RCB-19-9(PDI=7.5) and PM-160 (PDI=9) with resistant reaction to Alternariaster leaf spot whereas RSLP-89, RSLP-99 and PM7 recorded medium resistance reaction in post-flowering stage.

Genetic variability studies of yield, its attributing traits and oil content in RHAlines of sunflower (Helianthus annuus L.)

Sunflower inbred lines (RHA) derived from different sources with Rf gene were evaluated during 2018- 2020.Genetic variability, phenotypic and genotypic coefficients of variation, heritability and genetic advance were assessed for seven traits related to seed yield, its attributing traits and oil content in 50 RHA lines of sunflower. The analysis of variance revealed highly significant differences for all the characters among the RHA lines. The magnitude of differences between PCV and GCV was relatively low for all the traits, indicating less environmental influence. The estimates of GCV and PCV were high for seed yield/plant. High heritability in broad sense estimates (&gt;90%) were recorded for all the traits under study indicating, the predominance of additive gene action and selection of RHA lines based on these characters would be more valid and selected RHA lines are likely produce high yielding hybrids. Effective for target plant selection in early generation.

Evaluation of sunflower (Helianthus annuus L.) germplasm lines for genetic diversity

In the present investigation, estimation of the genetic diversity among thirty five germplasm lines of sunflower was undertaken by using Mahalanobis D2 analysis. Based on the relative magnitude of D2 values, the experimental material was distributed into six clusters. Out of six clusters, cluster I was the largest comprising of nineteen lines. Single plant yield, plant height, volume weight together contributed maximum (82.85 %) to the total genetic divergence. Maximum inter cluster distance was exhibited between clusters II and IV. The greater the distance between two clusters, the wider the genetic diversity among the genotypes of these clusters. Hence, hybridization between the genotypes from these clusters would produce high heterotic recombinants.

Identification of sources of resistance to leafhopper(Amrasca biguttula biguttula) in sunflower

Among the 135 sunflower lines evaluated during summer, 2020-22, ten lines were confirmed resistant to leafhopper. Leafhopper (Amrasca biguttula biguttula) is a major sucking pest that occur mostly in rabi/summer season and cause yield loss of up to 40% in India. Chemical control effects pollinators. Host plant resistance is an ecologically and economically promising alternative pest management tool. Presently, none of the available hybrids are leafhopper resistant. Leafhopper resistant cultivars significantly reduces plant protection cost. Stable sources of resistance are needed to be identified to develop resistant cultivars.

Identification and validation of novel QTL associated with powdery mildew (Golovinomyces cichoracearum (DC.) V.P. Heluta.) resistance in sunflower (Helianthus annuus L.)

Sunflower (Helianthus annuus L.; 2n=2x=34) is an important annual oilseed crop cultivated worldwide. In the recent past, powdery mildew disease has evolved as a significant constraint for yield and quality production in sunflower crop. Hence, a F2 mapping population was developed from a cross COSF 15B x IR6 to identify quantitative trait loci (QTL) associated with powdery mildew resistance in sunflower. F2:4 recombinant lines of this population were screened along with parents and scored for powdery mildew resistance during Dec-Feb 2021-22. Per cent disease index (PDI) was calculated from the data taken 75 days after sowing (DAS) using a 0-9 score scale. Genetic linkage map was constructed with 92 SSR markers which covered 1053.3 cM. The QTL analysis resulted in the detection of one QTL in LG10 for PDI. It has 2.54 LOD and accounted for 12.25 per cent phenotypic variation. The flanking markers viz., ORS684 and ORS1110 have a flanking distance of 1.7 cM and validated with a set ofpopulation revealed that 24% and 28% PVE respectively. Hence, it may be concluded that markers ORS684 and ORS1110 can be effectively utilized for marker assisted breeding programme to develop the sunflower lines resistant to powdery mildew.

Computational identification, characterization, and expression analysis of MLO genes in two powdery mildew resistant and susceptible lines of sunflower

Sunflower is one of the major oilseeds producing crops in the world. However, the crop production is affected by powdery mildew in the tropics, caused by a fungal pathogen Golovinomyces latisporus. A step towards developing genetic resistance is by identifying potential genes involved. The MLO genes when silenced provide durable and broad-spectrum resistance. In this study, we identified the MLO gene family in the genome of Sunflower using computational methods. We analyzed the chromosomal distribution, gene structure conserved motifs, and phylogenetic relationship of sunflower MLO genes with MLO genes of other species. A total of 38 MLO genes were identified which are distributed unevenly on the chromosomes with varied intron/exon gene structures. These were phylogenetically distributed into six different groups. The cis elements identified in the promoter region had hormone responsive, stress responsive, development related elements along with transcription factors. We developed recombinant inbred lines by crossing H. annuus and H. praecox (F7 generation). Further, we performed RNAseq analysis of transcriptomes sequenced from powdery mildew infected leaf samples of PMR-16 (resistant) and PMS-27 (susceptible) varieties of the recombinant inbred lines. Expression analysis revealed 12 differentially expressed genes between both varieties. Our results can be used as a reference for future functional studies.

Correlations of confectionary seed traits in different head zones sunflower

Abstract It is proposed to study the qualities of sunflower seeds in three zones of location in the head. Moderate negative correlations of the sign of the number of lateral heads (branching) in sunflower lines from the mass of 1000 seeds, the number of rows, seeds in a row, the total number of seeds and the diameter of the head were established (r = −0.5 to −0.53* on the Chedokk scale). The dependence of the number of seeds in the head on its size was confirmed (r = 0.83). In particular, we obtained a high positive correlation between the signs of the number of rows in the head and the number of seeds in the row with the size of the head (0.71 and 0.72). It was established that the mass of 1000 seeds of the first tier has correlations with the number of seeds in a row and the number of rows (r = 0.32 and 0.39), which are attributed only to the group of noticeable ones. This indicates the possibility of combining in one plant a large number and size of seeds in the head. It was found that changes in the size and weight of the seeds in the head by zone occur in hybrids and lines gradually, while the variety shows only a slight decrease in the size and weight of the seeds in the third zone. The largest quantity and the best confectionary quality of seeds was provided by the Zaporizhzhya Confectionery variety. In hybrids, the output of seeds weighing 90–80 g from one head reached only 1000 pieces. The potential to increase the number of seeds in heads in hybrids is present, but the size of the seeds is critical. With the available average weight of 1000 seeds: 90 g in the best maternal line and 70 in the best paternal line, the hybrids only approached the 100 g mark.

Generation of high oleic acid sunflower lines using gamma radiation mutagenesis and high-throughput fatty acid profiling.

Sunflower (Helianthus annuus L.) is the second most important oil seed crop in Europe. The seeds are used as confection seeds and, more importantly, to generate an edible vegetable oil, which in normal varieties is rich in the polyunsaturated fatty acid linoleic acid. Linoleic acid is biosynthesized from oleic acid through activity of the oleate desaturase FATTY ACID DESATURASE 2 (FAD2), which in seeds is encoded by FAD2-1, a gene that's present in single copy in sunflowers. Defective FAD2-1 expression enriches oleic acid, yielding the high oleic (HO) acid trait, which is of great interest in oil seed crops, since HO oil bears benefits for both food and non-food applications. Chemical mutagenesis has previously been used to generate sunflower mutants with reduced FAD2-1 expression and here it was aimed to produce further genetic material in which FAD2-1 activity is lost and the HO trait is stably expressed. For this purpose, a sunflower mutant population was created using gamma irradiation and screened for fad2-1 mutants with a newly developed HPLC-based fatty-acid profiling system that's suitable for high-throughput analyses. With this approach fad2-1 knock-out mutants could be isolated, which stably hyper-accumulate oleic acid in concentrations of 85-90% of the total fatty acid pool. The genetic nature of these new sunflower lines was characterized and will facilitate marker development, for the rapid introgression of the trait into elite sunflower breeding material.

The top Bulgarian contributions to sunflower breeding

Abstract The sunflower (Helianthus annuus L.) is a fundamental oil-yielding culture for Bulgaria and the world and thus, special attention is paid to it. Various selection methods have been used over the years and as a result of successful breeding programs new sunflower forms, lines (В/А and R) and hybrids (oil and confectionery type) were created in Bulgaria. Some of these new forms have new plant architectonic, different vegetation periods, seeds with different sizes and coloration, high combining ability, resistance to diseases, the parasite Broomrape and some herbicides, high seed oil and fatty acid content, genes for restoration of fertility (Rf genes), and different types of cytoplasmic male sterility (CMS).