Freesia Cultivars Research Articles

Biological effect of gamma and electron beam to target turning X-ray irradiation on two varieties of freesia in M3 generation

The study was carried out to explore the effects of 60Co-γ irradiation and electron beam to target turning X-ray (EBTTX) irradiation in the M3 generation to accelerate the breeding process of freesia. Bulbs of two varieties of freesia “Freesia armstrongii W. Watson” and “Freesia corymbosa (Burm.f.) N. E. Br” were exposed to 4 doses of 60Co-γ and EBTTX irradiation (25, 50, 75, and 100 Gy). The stimulatory effect on germination rate, survival rate, plant height, leaf number, leaf area, root number, root length, flowering plant rate, and pedicel length of two freesia cultivars at 25 Gy of 60Co-γ irradiation dose was better than EBTTX in M3 generation. High irradiation dose exhibited stronger inhibitory effects on these plants' growth parameters and even the survival rate of two freesia cultivars was 0.00% at 100 Gy irradiation dose for both types of irradiation. The total chlorophyll content of freesia “Freesia armstrongii W. Watson” and “Freesia corymbosa (Burm.f.) N. E. Br” reached the maximum under the radiation dose of 25 Gy. With the increase in radiation dose, the content of MDA, SOD, and POD in the leaves of both varieties of freesia increased gradually. In the M3 generation of the two freesia varieties, five new mutant plants such as dwarf plants, altered flower color, and increased petal numbers were found. A high frequency of mean mutations was found in EBTTX irradiated plants (4.16% and 3.3%) than in gamma-irradiated plants (2.4% and 2.5%) at 50 Gy as compared with control in Freesia armstrongii W. Watson and Freesia corymbosa (Burm.f.) N. E. Br.

Bioresource collection of flower crops in FRC SSC of RAS and its use in breeding research

The paper deals with topical issues of introduction and breeding research in the framework of import substitution in the floriculture industry. An extensive gene pool of flower crops has been mobilized at the Federal Research Centre the Subtropical Scientific Centre of the Russian Academy of Sciences (Sochi). On the basis of the Centre’s collections, apart from scientific purposes of conserving biodiversity, researching plants resistance and adaptability, as well as developing methods for studying cultivar samples, etc., there are practical tasks of obtaining planting material and cut flowers, including off-season periods, and using them in various forms of floral decoration, which are being solved. Bioresource collections include 1,499 cultivar samples, of which 34.29 % are perennial herbaceous plants, 20.61 % are bulbous and bulbotuberiferous, 16.94 % are irises, 14.34 % are pelargoniums, 9.47 % are species of natural flora, 4.34 % are chrysanthemums. The collections are also the basis for conducting breeding research in order to create highly ornamental, original, environmentally resistant and productive cultivars in the Centre with different flowering periods. Over the past 10 years, 85 cultivars of flower crops have been created (including 36 pelargoniums, 15 freesias and anemones, 12 chrysanthemums, 4 gerberas, 2 primroses, 1 tulip). The obtained cultivars are highly ornamental and resistant to bio- and abiotic factors. Freesia, anemone and pelargonium cultivars registered in the State Register of Breeding Achievements of the Russian Federation belong only to the FRC SSC of RAS.

Composition of Flavonoids in the Petals of Freesia and Prediction of Four Novel Transcription Factors Involving in Freesia Flavonoid Pathway.

Freesia hybrida is rich in flower colors with beautiful flower shapes and pleasant aroma. Flavonoids are vital to the color formation of its flowers. In this study, five Freesia cultivars with different flower colors were used to study on the level of accumulation of their flavonoids and expression of flavonoid-related genes and further explore new novel transcription factor (TF). Ultra-high-performance liquid chromatography and VION ion mobility quadrupole time-of-flight mass spectrometer (UPLC-Q-TOF-MS) were used to determine the flavonoids. Combined with transcriptome sequencing technology, the molecular mechanism of the flavonoid metabolism difference in Freesia was revealed. A total of 10 anthoxanthin components and 12 anthocyanin components were detected using UPLC-Q-TOF-MS. All six common anthocyanin aglycones in high plants, including cyanidin, delphinidin, petunidin, peonidin, malvidin, and pelargonidin, were detected in Freesia at first time in this study. In orange, yellow, and white cultivars, anthoxanthins gradually decreased with the opening of the petals, while in red and purple cultivars, anthoxanthins first increased and then decreased. No anthocyanin was detected in yellow and white cultivars, while anthocyanins increased with the opening of the petals and reached their maximum at the flowering stage (S3) in other three cultivars. The correlation analysis revealed that the color of Freesia petals was closely related to the composition and content of anthoxanthins and anthocyanins. Petals of five cultivars at S3 were then selected for transcriptome sequencing by using the Illumina Hiseq 4000 platform, and a total of 100,539 unigenes were obtained. There were totally 5,162 differentially expressed genes (DEGs) when the four colored cultivars were compared with the white cultivar at S3. Comparing all DEGs with gene ontology (GO), KEGG, and Pfam databases, it was found that the genes involved in the flavonoid biosynthesis pathway were significantly different. In addition, AP2, WRKY, and bHLH TF families ranked the top three among all differently expressed TFs in all DEGs. Quantitative real-time PCR (qRT-PCR) technology was used to analyze the expression patterns of the structural genes of flavonoid biosynthesis pathway in Freesia. The results showed that metabolic process was affected significantly by structural genes in this pathway, such as CHS1, CHI2, DFR1, ANS1, 3GT1, and FLS1. Cluster analysis was performed by using all annotated WRKY and AP2 TFs and the above structural genes based on their relatively expression. Four novel candidate TFs of WRKY and AP2 family were screened. Their spatiotemporal expression patterns revealed that these four novel TFs may participate in the regulation of the flavonoid biosynthesis, thus controlling its color formation in Freesia petals.

Biological effects of electron beam to target turning X-ray (EBTTX) on two freesia (Freesia hybrida) cultivars.

Electron beam to target turning X-ray (EBTTX) is an emerging irradiation technology that can potentially accelerate the breeding process of plants. The biological effects of EBTTX irradiation on the two freesia cultivars (the red freesia and the purple freesia) were investigated by establishing an irradiation-mediated mutation breeding protocol. The germination rate, survival rate, plant height, leaf number and area, root number and length of the two freesia cultivars decreased following different irradiation doses (25, 50, 75, and 100-Gy). A high irradiation dose exhibited stronger inhibition effects on these plant growth parameters, and the survival rate of the two freesia cultivars was 0.00% following the 100-Gy irradiation treatment. The median lethal dose (LD50) based on survival rates was 54.28-Gy for the red freesia and 60.11-Gy for the purple freesia. The flowering rate, flower number, and pollen vigor were significantly decreased by irradiation treatment. At 75-Gy irradiation, the flowering rate, flower number and pollen viability of the two varieties reached the minimum, exhibiting strong inhibitory effects. Meanwhile, 75-Gy irradiation significantly decreased the chlorophyll content and increased the malondialdehyde (MDA) content of the two freesia cultivars. Furthermore, as the irradiation dose increased, the changes in the micro-morphology of the leaf epidermis and pollen gradually increased according to a scanning electron microscope (SEM) analysis. These results are expected to provide useful information for the mutation breeding of different freesia cultivars and other flowering plants.

Analysis of Relative Scent Intensity, Volatile Compounds and Gene Expression in Freesia "Shiny Gold".

Scent is one of the most important economic traits in Freesia hybrida. “Shiny Gold”, a popular cultivar in South Korea, is widely cultivated for its scent. The relative scent intensity of “Shiny Gold” was approximately 16% higher in full-bloomed flower when compared to the yellow bud stage, while tissue-specifically, tepals showed higher intensity in electronic-nose (e-nose) analysis. E-nose analysis also showed that the scent intensity of “Shiny Gold” was higher and lower than “10C3-424” and “10C3-894”, respectively, and was similar to “Yvonne”. These results correlated to those of the olfactory tests. In total, 19 volatile compounds, including linalool, β-ocimene, D-limonene, trans-β-ionone were detected in gas chromatography–mass spectrometry analysis. Among these, linalool was the major volatile compound, accounting for 38.7% in “Shiny Gold”. Linalool synthase and TPS gene expression corresponded to the scent intensity of the four cultivars, with the lowest expression in the “10C3-424”. TPS 2, TPS 3, TPS 5, TPS 6 and TPS 8 were highly expressed in both bud and flower in “Shiny Gold”, while the expression of TPS 4 was lower, relative to other TPS genes in both the flowering stages. These results may aid in enhancing scent composition in Freesia cultivars using marker-assisted selection.

Comparative analysis of photosynthetic indicators in freesia hybrids on the Black sea coast of Krasnodar region

The paper discusses some features in Freesia refracta pigment system and possible use of this option as a plant diagnostic characteristic on the resistance in limiting environments. The study included freesia cultivars and hybrid forms selected in the Russian Research Institute of Horticulture and Subtropical Crops, which had different flowering terms. A detailed analysis was provided on any changes in the photosynthetic pigments content during the growing process. There are parameters of slow chlorophyll fluorescence induction (vitality index, ratio of photosynthetic activity and estimated coefficient of photosynthetic activity) in the leaves of different cultivars and hybrid forms. In order to determine the dependences between photosynthetic pigments content and parameters of slow chlorophyll fluorescence induction in freesia cultivars and hybrid forms pair correlation coefficient; it was calculated between these features among all hybrids and cultivars in general. The relationship recorded between optical indicators, and structural features of the pigment system will allow us to develop a method of rapid diagnosis of photosynthetic activity in freesia on the Black Sea coast of the Krasnodar region.

First Report of Freesia sneak virus in Commercial Freesia hybrida Cultivars in Korea

In order to investigate the virus infection rate of commercial freesia cultivars in early February 2013, 19 freesia cultivars showing necrotic purple speckles or streaks on leaves, purple streaks parallel to the midrib, and necrotic speckles on leaves were collected from three different regions (Suwon and Icheon in Gyeonggi Province and Jeonju in North Jeonla Province) and used for virus detection. Nucleic acid extracts were analyzed for detection of major freesia-infecting viruses including Freesia sneak virus (FreSV) by reverse transcription (RT)-PCR with specific primer pairs. The FreSV CP gene was amplified using primer pair FreSV-F (5'-TTAGATAGTGAATCCATAAGCTGC-3') and FreSV-R (5'-ATGTCTGGAAAATACTCCGTCCAA-3'). The approximately 1.3-kb fragment of the FreSV amplified product was cloned and sequenced (GenBank Accession No. KC771891 to 98). The nucleotide sequences of CP gene of FreSV korean isolates showed 99.2 to 99.8% similarity to other FreSV isolates DQ885455, FJ807730, and GU071089, which are registered in GenBank. FreSV was detected from 71.7% of 138 plants tested while the infection rate of Freesia mosaic virus (FreMV) was 34.8%. Neither Bean yellow mosaic virus (BYMV) nor Tobacco rattle virus (TRV) were detected from any plants tested in this study. In certain cultivars, such as 'Bluebau' (II) and 'Pretty women,' most plants planted in the field showed purple streak symptoms on the leaves. In conclusion, FreSV was detected from some symptomatic freesia cultivars showing purple streak or speckles on leaves with or without necrotic spots and necrotic speckles on leaves. FreSV is currently widespread in Korea and some freesia plants were mixed infected with FreMV. FreSV has been occurring in the Netherlands for over 40 years (2). It is a plant virus in the family Ophioviridae and Ophiovirus genus. Once it occurs in freesia plantation fields, eradication is almost impossible because FreSV is transmitted by zoospores of Olpidium brassicae, which is a soilborne root-infecting fungus (3). Resting spores of O. brassicae can remain dormant in the soil and can be infective for 20 years (1). To produce virus-free freesia plants, growers should consider whether or not their fields are contaminated with O. brassicae carrying FreSV. To our knowledge, this is the first report of FreSV in freesia plants in Korea.

CDNA cloning and characterization of UDP-glucose: anthocyanidin 3-O-glucosyltransferase in Freesia hybrida

The enzyme that catalyzes the formation of the first stable anthocyanin in the biosynthesis of natural compounds is UDP-glucose: anthocyanidin 3-O-glucosyltransferase (UF3GT). A cDNA clone (Fh3GT1) encoding UF3GT was isolated from Freesia hybrida. Phylogenetic tree analysis indicated that Fh3GT1 was a novel member of glycosyltransferase, which was classified into monocot subgroups. Semi-quantitative RT-PCR analysis detected transcripts of Fh3GT1 in different organs of F. hybrida and in petals of Freesia cultivars of different colors, and the expression level reached the maximum at the fully opened stage of petals. Characterization of the enzymatic assays indicated that Fh3GT1 had a role in anthocyanin glycoside biosyntheses in vitro. To elucidate the function of Fh3GT1, RNA interference vector (pART-Fh3GT1i) was constructed, and introduced into Petunia grandiflora by Agrobacterium-mediated transformation. Integration of the Fh3GT1 in petunia genome was confirmed by PCR and Southern blotting. SqRT-PCR revealed that the endogenous Ph3GT1 mRNA expression levels decreased in transgenic lines compared with the wild-type. The content of total anthocyanin pigments also decreased with the reduction of mRNA transcript levels, and the transgenic petunia plants had significant changes on their flower colors. In summary, this work identified a UF3GT gene from Freesia hybrida and demonstrated a method to modify plant flower color by redirecting the anthocyanin biosynthesis.

TOTAL SOLUBLE SUGARS IN TULIP BULBS AND FREESIA CORMS DURING STORAGE

In general, bulbs and corms of ornamental plants are highly recommended to store in ambient temperature for certain periods of time depending on the production strategies. During the storage period, many physiological changes occur in bulbs and corms. In this study, total soluble sugars of tulip bulbs (Tulipa gesneriana L. 'Negrita' and 'Cassini') and freesia corms (Freesia reflecta Klatt. 'Polaris' and 'Aladin') were investigated during different storage conditions. The bulbs and corms were stored in either non-cold (18-25°C and 55-65% RH) or cold (5±1°C and 70-85% RH) storage conditions. Total soluble sugars and loss of weight in bulbs and corms stored in both conditions were evaluated for 120 days with 40 days intervals. Loss of weight in bulbs and corms increased linearly in both storage conditions. In general, total soluble sugar contents were higher in tulip than in freesia. In addition, significant varietal differences were detected between the cultivars. In tulip cultivars, total soluble sugar contents were higher in cold-stored bulbs than that in non-cold stored ones, whereas no significant difference between storage conditions was detected in corms of freesia cultivars. The results indicated significant differences between species as well as cultivars in response to storage conditions.

Distinct Respiration and Physiological Changes during Flower Development and Senescence in Two Freesia Cultivars

Two cultivars of Freesia hybrida, ‘Shangnong Jinhuanghou’ and ‘Shangnong Hongtaige’, were used to study the respiration rate and physiological responses during flower development and senescence. Phenotypically, the vase life of ‘Shangnong Hongtaige’ was significantly shorter than that of ‘Shangnong Jinhuanghou’. At the whole flower level, both cultivars displayed similar change patterns on respiration rate. However, the change patterns in tepals, stamens, and pistils showed some differences in the two cultivars. A respiratory climacteric existed in most organs in both cultivars except for the stamen of ‘Shangnong Jinhuanghou’. During flower development and senescence, the levels of soluble proteins and soluble sugars were very high at early stages, followed by a dramatic decrease, and the lowest levels occurred in wilted tepals in both cultivars. Superoxide dismutase (SOD) activities increased slightly at early developmental stages followed by a constant decrease in two cultivars, and SOD activities in ‘Shangnong Jinhuanghou’ were significantly higher than those in ‘Shangnong Hongtaige’. Peroxidase activities showed a constant increase before tepals started wilting followed by a decrease in wilted tepals in both cultivars. In both cultivars, electrolytic leakage and malondialdehyde (MDA) content in tepals increased with the progression of development and senescence. MDA content in ‘Shangnong Hongtaige’ was much higher than that in ‘Shangnong Jinhuanghou’. These results indicated that the respiratory climacteric, the decrease of antioxidant enzyme activities, the peroxidation of membrane lipid, and the loss of soluble compounds could be considered as indicators of flower senescence in Freesia.

Study on quality and quantity aspects of some new Freesia cultivars in the second year of culture.

Freesia hybrida is one of the most cultivated cut flowers worldwide. Modern technologies recommend cultivating Freesia in rotation with chrysanthemum and tomatoes, to avoid pests and diseases apparition into culture of that are the main cause of species degeneration. The greatest expenses in a Freesia culture from bulbs are made on the achievement of the bulbs but they compensate the quality and quantity of the flowers. In our research, the cultivars have been cultivated in a modern greenhouse and as we couldn’t do a rotation of crops, we prevented their apparition into culture by thermal disinfection of soil before setting the crops and pest control by preventing them with several treatments recommended in this matter. The results show that the lowest number of flower stalks was recorded by ‘Striped Sun’ cv. while ‘Troubadur’ cv. has shown a higher number of floral stalks in the second year. Other researched aspects have shown a diminution of the values to the first year. The greatest diminution of the floral stem length was recorded by ‘Algarve’ cv. while ‘Yvonne’ cv. has recorded greater values of the same character in the second year. The degeneration appeared different to the researched cultivars on the aspects mentioned in the paper, even if all had benefited of the same cultural conditions.

Volatile Compounds in the Flowers of Freesia Parental Species and Hybrids

Abstract For centuries, freesia has been one of the most important crops in the floriculture industry. Here, aqua‐space samples collected from entire flowers of diploid Freesia refracta, three tetraploid freesia cultivars, and interspecific hybrids of three tetraploid freesia cultivars were analyzed using gas chromatograph coupled with mass selective detector. In all, 75 different compounds were identified. The compounds were mainly terpenes, hydrocarbons, alcohols, fatty acid esters and aromatic class compounds. Among these, linalool was detected from all the sweet‐scented flowers except for scentless white tetraploid F. hybrida. Stable inheritance of linalool between F. hybrida and their F1 progeny was observed. Based on the present analyses, the relationship between the aroma of freesia and linalool was discussed.

COMPARISON OF SILVER THIOSULFATE WITH 1-METHYLCYCLOPROPENE ON 19 CUT FLOWER TAXA

The effects of silver thiosulfate (STS; AVB) and 1-methylcyclopropene (1-MCP; Ethylbloc) were determined on 14 commonly-grown cut flower species, represented by one to three cultivars per species. Stems were unpacked, sorted, and placed in either deionized water (DI) and subjected to 1-MCP (740 nL L') or ambient air for 4 h or DI plus STS at either 0.1 mM (Alstroemeria) or 0.2 mM (all other species) for 4 h. After treatment, stems were removed, placed in polyethylene sleeves and stored either wet in DI water or dry in plastic-lined floral boxes at 5°C in the dark for 4 days. After storage bunches were placed in DI water under 12 h (76 to 100 μmol m -2 s -1 ) light per day. Flowers were monitored daily to determine the end of wholesale vase life, which was designated as the first day a change was noticed in the flower or inflorescence that would typically prevent it from being sold by a wholesaler or retailer. The consumer vase life was also recorded for each stem and was designated as the day a typical consumer would dispose of it. The 19 cut flower taxa could be organized into four groups based on effectiveness of STS and 1-MCP: (1) Both STS and 1-MCP increased vase life but STS was more effective: Dianthus caryophyllus (all three cultivars), Bouvardia, Lilium (Asiatic), and Lathyrus odorata. (2) Both STS and 1-MCP prevented the negative effects of dry storage: Freesia (both cultivars) and Chamelaucium (one cultivar). (3) STS increased vase life while 1-MCP did not: Alstroemeria, Delphinium, Matthiola, and Gypsophila. (4) STS and 1-MCP either had no effect or a negative effect: Consolida, Eustoma, Ranunculus, Antirrhinum, and Chamelaucium (one cultivar).

Identification of a Genome-specific RAPD Marker to Freesia corymbosa (Burm. f.) N. E. Br. among Freesia Cultivars (F. hybrida hort.) to Detect their Lineage

A RAPD marker genome-specific to pink-flowered Freesia corymbosa (Burm. f.) N. E. Br., which was generated by using OPG-12 primer, is a DNA fragment with 837 bp nucleotide sequence. A pair of primers were also designed for generating a 637 bp SCAR marker. Both RAPD and SCAR markers were detected in all three accessions of Freesia corymbosa and absent in 32 accessions of eight Freesia species tested. The markers were detected in most cultivars having red, pink, blue, purple and violet perianths, which support our hypothesis that pinkishtone perianth color of freesia cultivars originated from the pink-flowered Freesia corymbosa. However, a SCAR band at 637 bp appeared in some yellow- and white-flowered cultivars. The lineage of freesia cultivars is discussed.

First Report of Phytoplasma Infection in Freesia Plant.

Disease symptoms including leaf chlorotic and necrotic spots and stripes resembling freesia leaf necrosis (disease of unknown etiology [2]) were observed in freesia (Freesia × hybrida Klatt.) plants (cvs. Aladyn, Blue Lady, Cortine, Gompy, and White Rapid) naturally infected with Freesia mosaic virus (FMV) and grown in the greenhouse in Poland. The aim of this work was to study the association of the leaf symptoms occurring in freesia cultivars with phytoplasma infection and to identify it. To detect the possible presence of phytoplasmas in freesias, plants showing leaf symptoms (five cultivars) and symptomless plants ('Blue Lady', 'Cortine', and 'Gompy') were assayed for the presence of phytoplasma 16S rDNA fragment by polymerase chain reaction (PCR). For phytoplasma detection samples of young leaves and corms of 15 symptomatic and five symptomless freesias were taken. The samples were collected from the selected plants infected with FMV. In addition, leaf samples from healthy Catharanthus roseus plants and those infected with AKV reference strain of aster yellows (AY) phytoplasma group, subgroup I-B (supplied by W. Jarausch, INRA Bordeaux, France), were included for comparison. The amplification was performed using the universal-rA/fA or R16F1/R0 and group specific-R16(I)F1/R1 phytoplasma primer pairs (1). Phytoplasma identification was accompanied by digestion with AluI and MseI restriction endonucleases and restriction length polymorphism (RFLP) analysis of the R(I)F1/R1 or rA/fA products. DNA amplification product was observed in all nested PCRs containing template DNA derived from the leaves and corms of all symptomatic as well as symptomless and FMV-affected freesias except symptomless freesia 'Cortine'. Based on RFLP analysis of PCR products and the comparison of the RFLP patterns with those of the strain AKV of aster yellows phytoplasma group (AY I-B), the associated phytoplasmas were identified as phytoplasma 16S rRNA group I, subgroup B. This work provides the first evidence that freesias examined were naturally infected with aster yellows phytoplasma. Detection of phytoplasma in diseased and symptomless but FMV-affected freesias underlines the need to know the role of this pathogen in the etiology of freesia diseases.

Assimilative Lighting with High-pressure Sodium Lamps Reduces Freesia Quality

Four freesia cultivars were exposed to 24 hour·day-1 high-pressure sodium (HPS) lighting during various stages of their development. Upon emergence, freesia plants were exposed to the following four lighting treatments: 1) ambient; 2) ambient until shoot length was 5 to 8 cm followed by HPS lighting until flowering; 3) HPS lighting until shoot length was 5 to 8 cm followed by ambient lighting; and 4) continuous HPS lighting. Supplemental HPS lighting was provided at 37 μmol·m-2·s-1 at plant level in a glasshouse. Continuous lighting or lighting during flower development hastened flowering but reduced the number of flowering stems per corm, as well as stem length and weight. Lighting during the vegetative and flower initiation periods produced minor effects. The main benefit of supplemental lighting was found in total corm weight.

Leaf-yellowing in combination with corm necrosis in freesia caused by bean yellow mosaic virus: Factors involved in syndrome development

In freesia cv. Aurora grown in the field for cutflower production, a disease occurred with symptoms of leaf-yellowing in combination with corm necrosis (LYCN). It is shown that this disease is caused by bean yellow mosaic virus (BYMV). No differences in symptoms of LYCN were observed between the freesia cultivars Aurora, Imperial and Rose Marie. Most BYMV isolates gave rise to LYCN; the isolates from crocus andIxia sp. did not. LYCN was stimulated by a high BYMV concentration in the inoculum, a temperature above 20°C, inoculation soon after emergence of the freesias, and by the absence of freesia mosaic virus. Freesias with mosaic symptoms and infected with a cross-protecting BYMV strain, did not show symptoms of leaf-yellowing and/or corm necrosis after inoculation with BYMV-Cm. The presence of the unknown agent causing leaf necrosis in freesias did not have an influence on symptom development after infection with BYMV.