Cultivated Sunflower Helianthus Annuus Research Articles

A Recombination Suppressed Region of Sunflower (<i>Helianthus annuus</i> L.) Linkage Group 13 Covers Restoration of Fertility (<i>Rf1</i>) and Downy Mildew Resistance (<i>Pl</i>) Gene Clusters

A number of genes that control valuable for breeding traits introgressed from wild relatives, i.e. pollen fertility restoration, resistance to fungal diseases (downy mildew and rust), are mapped on linkage group 13 of the cultivated sunflower Helianthus annuus L. genome. In sunflower and other plants, the recombination in the chromosome regions containing resistance genes can be suppressed that is favourable for marker assisted selection with applying molecular markers linked to these loci. The joint inheritance of the loci Rf1 (the phenotypic marker is fertility restoration trait) and Pl5/Pl8 conferring resistance to many races of Plasmopara halstedii (Farl) Berl. De Toni (the STS marker Ha-P1) was studied in the F2 generation of hybrids between a sterile line VIR 116A lines and pollen fertility restorers from sunflower VIR collection. In the crossing VIR 116А × VIR 740, the frequency of recombination between the loci Pl5Pl8 and Rf1 constituted 8.61 whereas in the crosses VIR 116А × VIR 195 and VIR 116А × VIR 80 turned out to be twice as high. In all examined F2 populations the absence of phenotypic class of sterile plants possessing paternal Нa-Р1 marker variant was mentioned. It has been shown by the cytological analysis that pollen fertility indices are most probably determined by the plant genotype rather than the male gametophyte allelic constitution. A deficiency of a recombinant F2 class was proposed to be associated with embryonic lethality, i.e. the collapse of zygotes carrying the recessive allele of fertility restoration gene and a specific allele of the resistance (susceptibility) gene obtained from the male parent.

Пыльцевой анализ растений различных генотипов подсолнечника

Pollen analysis makes it possible to determine the reproductive potential of sunflower plants by the morphological characteristics of pollen grains with the aim of breeding to increase yields. The research was carried out in 2019–2020 at V.S. Pustovoit All-Russian Research Institute of Oil Crops, Krasnodar. The objects of the research were plants of cultivated sunflower Helianthus annuus L.: four hybrids – Factor, Typhoon, Oxy and NK Brio, confectionery variety Djinn, two parental lines of the hybrid Oxy – VK876 B and VK195, as well as a perennial wild growing hexaploid species H. tuberosus L. Pollen was stained with acetoorcein and viewed under a microscope Micros MS 20. The diameter of pollen grains in the hybrids Factor, NK Brio, Typhoon, Oxy, the line VK195 and the cultivar Djinn varied from 34 to 31 μm. The line VK876 B and H. tuberosus were characterized by the lowest values of this trait – 29 and 27 μm, respectively. For the line VK876 B and the hybrid Oxy, significant morphological heterogeneity of pollen was observed, which was expressed in a correspondingly high proportion of abnormal pollen grains – 34 and 26%. At the same time, there was a two-peak distribution of the values of the diameter of pollen grains. The morphological heterogeneity of the pollen grains of the hybrid Oxy is associated with the dominant inheritance of this trait from the maternal CMS-form VK876 A, since the paternal line VK195 has a normal characteristic of pollen grains. The pollen of the hybrid NK Brio showed a significantly higher (by 25%) seed setting in crossing with the CMS tester than that of the hybrid Oxy, which confirms the assumption that there is a relation between an increased proportion of abnormal pollen grains and reduced pollen fertility.

Combined linkage and association mapping of flowering time in Sunflower (Helianthus annuus L.)

Association mapping and linkage mapping were used to identify quantitative trait loci (QTL) and/or causative mutations involved in the control of flowering time in cultivated sunflower Helianthus annuus. A panel of 384 inbred lines was phenotyped through testcrosses with two tester inbred lines across 15 location×year combinations. A recombinant inbred line (RIL) population comprising 273 lines was phenotyped both per se and through testcrosses with one or two testers in 16 location×year combinations. In the association mapping approach, kinship estimation using 5,923 single nucleotide polymorphisms was found to be the best covariate to correct for effects of panel structure. Linkage disequilibrium decay ranged from 0.08 to 0.26cM for a threshold of 0.20, after correcting for structure effects, depending on the linkage group (LG) and the ancestry of inbred lines. A possible hitchhiking effect is hypothesized for LG10 and LG08. A total of 11 regions across 10LGs were found to be associated with flowering time, and QTLs were mapped on 11LGs in the RIL population. Whereas eight regions were demonstrated to be common between the two approaches, the linkage disequilibrium approach did not detect a documented QTL that was confirmed using the linkage mapping approach.

Cultivated Helianthus annuus differs from two wild relatives in germination response to simulated drought stress

Wild sunflowers are a source of desirable traits for improving cultivated sunflower Helianthus annuus (ANN). Two wild species of sunflower, H. argophyllus (ARG) native to coastal sand dunes and H. niveus ssp. tephrodes (TEPH) native to the desert sand dunes, have been hypothesized to be drought resistant. We tested the expectation that these wild species would have higher percent germination and more uniform germination under simulated drought stress conditions compared to cultivated ANN. In a growth chamber study, we assessed germination of ANN, ARG and TEPH (three representative accessions for each species) under four osmotic stress treatments imposed using polyethylene glycol to simulate varying levels of drought stress: 0, -0.4, -0.8 and -1.2 MPa. As expected, all three species responded to increasing simulated drought stress with decreased percent germination assessed after seven days and delayed germination timing and uniformity assessed with logistic regressions. ARG responded marginally better than ANN with a greater percent germination at -1.2 MPa and greater uniformity at 0 and -0.4 MPa. Although the ARG advantage was small, this suggests that ARG × ANN recombinant hybrids may deserve further investigation to see if desirable alleles can be identified for improving cultivated ANN germination and establishment under mild drought conditions. In contrast, TEPH responded with substantially lower percent germination and less uniformity than ANN, suggesting that it is unlikely that TEPH will be useful as a donor of desirable drought resistance alleles.

Plant response to lead in the presence or absence EDTA in two sunflower genotypes (cultivated H. annuus cv. 1114 and interspecific line H. annuus × H. argophyllus)

The aim of the present work was to study the response of two sunflower genotypes (cultivated sunflower Helianthus annuus cv. 1114 and newly developed genotype H. annuus × Helianthus argophyllus) to Pb medium-term stress and the role of exogenously applied EDTA in alleviating Pb toxicity in hydroponics. Plant growth, morpho-anatomical characteristics of the leaf tissues, electrolyte leakage, total antioxidant activity, free radical scavenging capacity, total flavonoid content, and superoxide dismutase isoenzyme profile were studied by conventional methods. Differential responses of both genotypes to Pb supplied in the nutrient solution were recorded. Pb treatment induced a decrease in the relative growth rate, disturbance of plasma membrane integrity, and changes in the morpho-anatomical characteristics of the leaf tissues and in the antioxidant capacity, which were more pronounced in the cultivated sunflower H. annuus cv. 1114. The new genotype demonstrated higher tolerance to Pb when compared with the cultivar. This was mainly due to increased photosynthetically active area, maintenance of plasma membrane integrity, permanently high total antioxidant activity, and free radical scavenging capacity as well as total flavonoid content. The addition of EDTA into the nutrient solution led to limitation of the negative impact of Pb ions on the above parameters in both genotypes. This could be related to the reduced content of Pb in the roots, stems, and leaves, suggesting that the presence of EDTA limited the uptake of Pb. The comparative analysis of the responses to Pb treatment showed that the deleterious effect of Pb was more pronounced in the cultivated sunflower H. annuus cv. 1114. The new genotype H. annuus × H. argophyllus was more productive and demonstrated higher tolerance to Pb medium-term stress, which could indicate that it may possess certain mechanisms to tolerate high Pb concentrations. This character could be inherited from the wild parent used in the interspecific hybridization. The ability of EDTA to prevent Pb absorption by the plants could underly the mechanism of limiting of the negative impact of Pb ions. Hence, EDTA cannot be used to enhance Pb absorption from nutrient solution by sunflower plants for phytoremediation purposes.

Obtención de híbridos intergenéricos Helianthus annuus x Tithonia rotundifolia y su análisis morfológico y molecular

Se realizó el cruzamiento entre el girasol cultivado Helianthus annuus y la especie silvestre con potencial ornamental Tithonia rotundifolia. De tres materiales cultivados: AN-3, Primavera y HA 89, sólo se tuvo éxito con la línea pública de girasol cultivado HA 89 como progenitor femenino. A su vez el masculino fue una población de T. rotundifolia recolectada en el estado de Guerrero, México. Se produjeron 826 aquenios híbridos bien desarrollados, con una tasa de éxito de cuatro en 1000 aquenios potenciales. Dentro de una muestra de 49 plantas establecidas en el campo experimental, se observaron dos clases fenotípicas: a) individuos con muchas inflorescencias pequeñas y b) otros con cabezuela solitaria grande y con pocas o ninguna inflorescencia axilar. Ambos tipos fueron caracterizados morfológicamente y presentaron rasgos claramente híbridos. Además, se analizó la huella genética, a través del polimorfismo en la longitud de los fragmentos amplificados (AFLPs), de una muestra de diez tríos familiares de cruzamientos, con un promedio de 28 polimorfismos por trío. El análisis de huella genética de las plantas complementó al estudio morfológico, permitió constatar la naturaleza híbrida de las progenies y descartar el fenómeno del cruzamiento parcial. Todas las plantas experimentales obtenidas resultaron ser estériles. Del presente trabajo se desprende que se requiere de manipulación cromosómica o técnicas de cultivo de tejidos para el desarrollo de híbridos fértiles con potencial ornamental.

Genomic instability in sunflower interspecific hybrids

The expression of genomic instability was studied at the phenotypical (morphological characters, electrophoretic spectra of seed storage proteins) and molecular (DNA amplification products) levels in interspecific hybrids (ISHs) from crosses of inbred lines of cultivated sunflower Helianthus annuus with perennial species of the genus Helianthus and in introgressive lines (ILs) produced on their basis. Unstable state of the locus determining the trait of lower branching was proved by the method of hybridological analysis. It was shown with the use of RAPD markers that the IL genome is characterized by instability even after long-term inbreeding (in generations F8-F12). In progenies of different combinations of interspecific crosses, identical polymorphous variants-were revealed for a seed storage protein, helianthinin, and for DNA fragments homologous to structural genes of functionally important proteins, suggesting the nonrandom character of ISH genome variation. This variation may be determined by genome reorganizations under the action of a genome shock induced by interspecific hybridization. The factors inducing reorganizations in the genome include the activity of mobile genetic elements (MGEs). Using primers specific to different MGE families, nucleotide sequences with a high level of homology to the sequences of fragments of the mobile elements MuDR, Far1, CACTA, Stowaway, and Tourist were identified in the sunflower genome. The possibility of using MGE fragments for sunflower genotyping was demonstrated.

Characterization of Hybrids, forms and Lines, Obtained from Interspecific Hybridization of Cultivated Sunflower Helianthus Annuus L. with Wild Species of Genus Helianthus

ABSTRACTThe interspecific hybrids, produced from crosses between cultivated sunflower (Helianthus annuus) and 16 wild species of genus Helianthus. The rate of cross-compatibility was different. The F1 plants had an annual or perennial growth cycle, branched stem and different anthocyanin coloration, vegetation period and seed colour. The hybrid nature of the some F1 plants was confirmed trough cytological, RAPD and electrophoretic analyses of seed storage proteins.Breeding of the new sunflower forms and lines was carried out through backcrossing to cultivated sunflower, self-pollination and sib-pollination and selection in generations. Most of the new obtained lines were resistant to some fungal diseases and the parasite Orobanche cumana and had high combining ability. It was established that some of them carried Rf genes for CMS Pet-1. Genes that controlled such characters as period of vegetation, plant height, type of branching, size and form of inflorerescence and seeds, high seed oil content were transferred, too. These characters make the lines suitable to including for heterosis breeding in sunflower.

Construction of an RFLP linkage map for cultivated sunflower

An RFLP linkage map was constructed for cultivated sunflower Helianthus annuus L., based on 271 loci detected by 232 cDNA probes. Ninety-three F2 plants of a cross between inbred lines RHA 271 and HA 234 were used as the mapping population. These genetic markers plus a fertility restoration gene, Rf 1, defined 20 linkage groups, covering 1164 cM of the sunflower genome. Of the 71 loci 202 had codominant genotypic segregation, with the rest showing dominant segregation. Thirty-two of the 232 probes gave multiple locus segregation. There were 39 clusters of tightly linked markers with 0 cM distance among loci. This map has an average marker-to-marker distance of 4.6 cM, with 11 markerless regions exceeding 20 cM.

Hybridization of Helianthus Praecox SSP. Praecox Engl. & Gray (2N = 34) with Cultivated Sunflower Helianthus Annuus L. (2N = 34). II. Investigations of Backcross and SIB-Pollinated Generations

Hybridization of Helianthus Praecox SSP. Praecox Engl. & Gray (2N = 34) with Cultivated Sunflower Helianthus Annuus L. (2N = 34). II. Investigations of Backcross and SIB-Pollinated Generations

Photosynthesis, dry matter accumulation and distribution in the wild sunflower Helianthus petiolaris and the cultivated sunflower Helianthus annuus as influenced by water deficits.

This study reports on the effects of water deficits on photosynthesis, plant growth and carbon allocation in the wild sunflower Helianthus petiolaris and in the cultivated sunflower Helianthus annuus grown under controlled conditions in the glasshouse. Water deficits reduced the rate of net photosynthesis and the dry weight of leaves, stems, roots and reproductive parts in both species. The root-to-shoot ratio of about 0.05 in H. petiolaris was lower than the root-to-shoot ratio of about 0.15 in H. annuus. Water stress did not affect the root-to-shoot ratio, but increased the percentage of roots at depth in H. annuus. The decrease in growth induced by water deficits was a consequence of a reduction in both leaf area production and net photosynthesis. Flowering occurred earlier in H. petiolaris than in H. annuus with a consequent earlier allocation of carbon to reproductive parts in the wild compared to the cultivated sunflower. The time to budding and flowering of either species was not altered by mild water stress, but was delayed by severe water deficits. During mild water stress carbon allocation to stems decreased, but that to reproductive parts increased. When plants were severely stressed and then rewatered the proportion af carbon allocated to leaves increased and the proportion allocated to stems decreased when compared to unstressed plants. The adaptative role of these features is discussed.