Dahlia Variabilis Research Articles

Evaluation of Different Dahlia (Dahlia variabilis L.) Hybrids for Better Growth and Yield of Flowers under Prayagraj Agro Climatic Conditions

The present investigation entitled, Evaluation of Different Dahlia (Dahlia variabilis L.) Hybrids for Better Growth and Yield of Flowers under Prayagraj Agro Climatic Conditions was under taken in the Department of Horticulture, Naini Agriculture Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, U.P. during winter season (2022 to 2023). The experiment was laid out with nine hybrids each replicated thrice in Randomized Block Design. Among the nine hybrids, hybrid Eternity (H2) reported significantly better performance in terms of plant growth parameters like plant height (89.93 cm), number of leaves per plant (133.87), number of branches per plant (11.53), average length of branches (59.67 cm) and stem diameter (2.61 cm). Whereas in terms of Yield parameters, hybrid Chandra Vaga (H7) reported significantly better performance like number of flowers per plant (20.30), number of flowers per plot (121.80), flower yield per ha (73,08,000).

Exogenous Application of Growth Regulators Improves the Growth and Quality of Dahlia variabilis L.

Dahlia (Dahlia variabilis L.), a bulb crop sold as cut flower, garden ornamental/potted plant, becomes a popular cut flower in the world. This experiment was designed to study the effects of foliar applied gibberellic acid, zinc, ascorbic acid, and thiamine on the growth and flower attributes of dahlia. The study was conducted under greenhouse conditions at the Floriculture Research Area, University of Agriculture, Faisalabad, Pakistan. There were thirteen treatment with three levels each; gibberellic acid, zinc sulphate, ascorbic acid, and thiamine. First, foliar application was done at vegetative stage (after 45 d of transplantation) and second, at the flowering stage. Application of gibberellic acid at 100 ppm significantly improved plant height (92.67 cm). Application of zinc at 0.50% produced the maximum number of flowers (28.47), diameter of flower (100.19 mm), and fresh weight of flower (11.16 g). Foliar application of thiamine increased nutrient accumulation in leaves of dahlia. The nitrogen contents (4.43 %) increased to maximum in response to treatment comprising ascorbic acid, whereas phosphorus content (1.41 mg g-1) and potassium contents (19.45 mg g-1) were at maximum in response to thiamine. The highest chlorophyll a (4.37 mg g-1) and b (2.04 mg g-1) contents were recorded in treatment comprising thiamine at 150 ppm. The highest carbohydrate contents (35.14%) were recorded in zinc application response. Application of thiamine significantly reduced the days of flowering and flower diameter. Overall, it can be recommended that application of thiamine at 150 ppm is more responsive to improve the growth and quality of dahlia flower as compared to gibberellic acid, zinc, and ascorbic acid.

Pre and postharvest characteristics of Dahlia pinnata var. pinnata, cav. As affected by SiO2 and CaCO3 nanoparticles under two different planting dates

Agriculture faces many challenges because of climate changes. The nutrients present in nano-sized form improve plant productivity, especially when used at the appropriate planting time. Field experiments were conducted as a factorial experiment for evaluating two planting dates (20th September and 20th October), foliar application with nanoparticles (NPs) including silica nanoparticles (SiO2-NPs) at 1.5 and 3 mM, calcium carbonate nanoparticles (CaCO3-NPs) at 5 and 10 mM and distilled water (control) on pre- and post-harvest characteristics of Dahlia pinnata var. pinnata Cav. The results indicate that the interactions during the late planting time (20th October) and exogenous applications of SiO2-NPs at 1.5 mM or CaCO3-NPs at 10 mM have improved plant growth including plant height, stem diameter, fresh and dry weights of plant, leaf area, inflorescence diameter, inflorescence stalk length, branches number, tuber numbers, inflorescences number on the plant, and the vase life. At the same time, insignificant differences appeared in the interaction during the planting dates and SiO2 or CaCO3 -NPs concentrations on inflorescence stalk diameter, total soluble solids, membrane stability index, maximum increase in fresh weight (FW), and Si and Ca contents. In addition, all exogenous applications of NPs at the late planting time promoted the plant growth characteristics like lignin %, cellulose %, inflorescence water content, change in FW, and total water uptake. Moreover, the controls through the two planting dates recorded the maximum change in water uptake and water loss values. In short, it can be recommended to use SiO2-NPs at 1.5 mM or CaCO3-NPs at 10 mM as a foliar application at the late planting time (20th October) for obtaining the optimum quantitative and qualitative parameters of D. pinnata.

FORMULASI SEDIAAN GEL EKSTRAK ETANOL UMBI DAHLIA ( Dahlia variabilis )TERHADAP PERTUMBUHAN BAKTERI Stapylococcus aureus PENYEBAB INFEKSI KULIT

Dahlia tubers (Dahlia variabilis) are plants that are often found in the higglands. The content in Dahlia tubers is able to inhibit microbial growth. The compound content of Dahlia tubers includes alkaloids, flavaanoids, sapnonins and tannins. One of the diseases caused by microbes is a skin infection. The purpose of this study was to make a gel preparation from the ethanolic extract of dahlia bulbs and to test whether the formulation was able to inhibit the growth of Stapylococcus aureus bacteria at concentrations of 4%, 6% and 8%. The extraction used in this research is the maceration method with 96% ethanol as solvent. Evaluation test of gel preparations and antibacterial activity test by discdiffusion method. Then the one way ANOVA test was carried out. The results showed different result in each formulation. Based on the average results of the antibacterial activity test, the inhibition zones of F) were 17,0 mm, F1 18,13 mm, F2 was 19,73 mm, and F3 8,23 mm. The results of this study conuluded that the extraction of Dahlia tubers had antibacterial activity due to the presence of an inhibitory zone around the paper disc in a petri dish. Further research needs to be done with other methods.

Green Indicators-An Ecofriendly Endpoint

Although acid-base titrations can be done using numerous indicators which are either synthetic or semi-synthetic, the investigation was started for natural compounds as the former ones result in polluting the habitat despite their limited availability, complicated method of preparation, and expensiveness. Equivalence point determination is the point of interest in neutralization titrations. With the change in pH, the indicators which are natural, usually end up giving a sharp color change. Plant-derived pigments that are of various shades and tints generally vary in their dyeing nature by altering pH. An indicator is a substance that exhibits the property of interchangeable color of the reaction mixture when reaching the vicinity of point with the change in pH. Acid-base titration indicators are normally weak acids or bases. Hibiscus rosa-sinensis, Ipomoea biloba, Dahlia pinnata, etc. are among the typical neutralization indicators that are extracted from plants. These natural Indicators are easily available and economical. In this review, we are discussing an overview of plant extracts, and natural pH indicators, and their significance in correspondence to analytical chemistry is illustrated.

Influence of Funneliformis mosseae in the growth and accumulation of dry biomass in Dalia plants

Objetive: in the production of Dahlia spp., only chemical fertilization has been used, and an option that has not yet been explored is the implementation of a microbial inoculant. Therefore, the objective of this study was to evaluate the effect of the mycorrhizal fungus Funneliformis mosseae on the growth and development of the dahlia (Dahlia variabilis var. Variegated dwarf). Design/methodology/approach: the seeds were sown in polyethylene bags containing a mixture of black soil, peat moss, and agrolite. A completely randomized design was used, and the treatment structure was 2x3 factorial. The study factors were F. mosseae, chemical fertilization, and substrate sterilization. Results: an analysis of variance was performed, and the mean values of the treatments were compared with Tukey’s test (α = 0.05). Conclusions: with the inoculation of F. mosseae, a significant increase was obtained in the study variables: plant height, stem diameter, number of buds and flowers per plant; leaf + stem, flower, root, and total biomass, compared to non-inoculated plants. A colonization of 89 % in the roots was recorded. A limitation of the study is that the effect of the inoculum on plant growth can vary according to the mycorrhiza species used. In conclusion, inoculation with Funneliformis mosseae increased growth and biomass accumulation in Dahlia plants.

Senescence in dahlia flowers is regulated by a complex interplay between flower age and floret position.

Mechanisms regulating flower senescence are not fully understood in any species and are particularly complex in composite flowers. Dahlia (Dahlia pinnata Cav.) florets develop sequentially, hence each composite flower head includes florets of different developmental stages as the whole flower head ages. Moreover, the wide range of available cultivars enables assessment of intraspecific variation. Transcriptomes were compared amongst inner (younger) and outer (older) florets of two flower head ages to assess the effect of floret vs. flower head ageing. More gene expression, including ethylene and cytokinin pathway expression changed between inner and outer florets of older flower heads than between inner florets of younger and older flower heads. Additionally, based on Arabidopsis network analysis, different patterns of co-expressed ethylene response genes were elicited. This suggests that changes occur in young inner florets as the whole flower head ages that are different to ageing florets within a flower head. In some species floral senescence is orchestrated by the plant growth regulator ethylene. However, there is both inter and intra-species variation in its importance. There is a lack of conclusive data regarding ethylene sensitivity in dahlia. Speed of senescence progression, effects of ethylene signalling perturbation, and patterns of ethylene biosynthesis gene expression differed across three dahlia cultivars ('Sylvia', 'Karma Prospero' and 'Onesta') suggesting differences in the role of ethylene in their floral senescence, while effects of exogenous cytokinin were less cultivar-specific.

Breeding Long Vase Life by Crossing and Selection for Five Generations in Dahlia (<i>Dahlia variabilis</i>) Cut Flowers, and Selection of Fourth-Generation Line 003-15 with Ultra-Long Vase Life

Genetic improvement of flower vase life is an important breeding target for ornamental plants. As the vase life of cut dahlia (Dahlia variabilis) flowers is very short, we initiated a conventional crossbreeding research program in 2014 to improve it. We evaluated the vase life of dahlia seedlings during summer (from July to early September) to develop dahlias that grow and bloom under high temperatures and have excellent vase life for Japanese summer conditions. Crossing and selection over five generations greatly improved vase life. The mean vase life increased from 4.4 days in the 1st generation, derived from 22 parental cultivars, to 8.0 days in the 5th generation, a net increase of 3.6 days. Mean vase life increased significantly by 1.6 days from the 4th to the 5th generation, indicating continued improvement. The mean vase life of the 12 lines selected from the 3rd and 4th generations ranged between 6.0 and 15.9 days in distilled water and from 7.8 to 14.6 days in GLA solution (10 g·L−1 glucose, 0.5 mL·L−1 CMIT/MIT [isothiazolinone derivatives], and 50 mg·L−1 aluminum sulfate). Vase life was further extended by 0.5 to 4.0 days using 6-benzylaminopurine (BA) sprays compared to GLA alone. In particular, the 4th-generation line 003-15 vase life was 13.8 to 15.9 days (2.5× that of ‘Kamakura’, a leading white dahlia cultivar in Japan) in distilled water, 12.0 to 14.6 days (1.8× to 2.2×) in GLA, and 13.9 to 15.3 days (1.7× to 1.9×) in GLA+BA in winter and spring. Cut flowers of line 003-15 harvested under high temperatures in July–August and at 28°C with GLA treatment also had long vase life. The pedigree of line 003-15 suggests that genes related to long vase life derived from ‘Micchan’ (with a long vase life) may have accumulated or duplicated in line 003-15. Finally, four selected lines, including 003-15, had high ethylene sensitivity, as 10 μL·L−1 ethylene treatment caused petal abscission in 2.0 to 2.8 days.

Bitki Gelişimini Teşvik Eden Rizobakteri ve Mikoriza Uygulamalarının Zinnia elegans L. ve Dahlia variabilis L.’in Gelişimine Etkisi

This study was carried out to determine the effects of plant growth-promoting rhizobacteria and mycorrhiza treatments on the development of Zinnia elegans L. ‘Zesty’ and Dahlia variabilis L. ‘Figaro Violet’ cultivars. In the study, a suspension was first prepared from bacterial isolates developed at 25±2 °C for 24 hours. The prepared suspensions were adjusted to an absorbance value of 0,3 at 600 nanometers in a spectrophotometer. D. variabilis seedlings were immersed in suspensions prepared from ZE-12, ZE-13 and ZE-12+ZE-13, Z. elegans seedlings were immersed in suspensions prepared from ZE-2, ZE-7, ZE-12, ZE-13, ZE-12+ZE-13 for 30 minutes. In addition, Z. elegans seedlings were kept in mycorrhiza prepared at a concentration of 5000 ppm for 10 seconds. At the end of the period, flower seedlings were planted in pots with a mixture of peat and perlite. As the control group, seedlings without rhizobacteria and mycorrhiza treatment were used in both cultivars. The experiment was established with 3 replications and 10 plants per replication. The applications made in the D. variabilis experiment remained the same as the control in all other parameters except root dry weight. ZE-13 application was effective on root dry weight. It was determined that the applications made in Z. elegans seedlings increased the flower stem thickness and the number of leaves, especially the ZE-13 application was the most effective application. In conclusion, with this study, it was revealed that rhizobacteria and mycorrhiza applications, which are of natural origin and do not harm the environment, have the potential to be used in ornamental plants cultivation, and that these applications should be expanded.

Rhizospheric microbiomics integrated with plant transcriptomics provides insight into the Cd response mechanisms of the newly identified Cd accumulator Dahlia pinnata.

Phytoremediation that depends on excellent plant resources and effective enhancing measures is important for remediating heavy metal-contaminated soils. This study investigated the cadmium (Cd) tolerance and accumulation characteristics of Dahlia pinnata Cav. to evaluate its Cd phytoremediation potential. Testing in soils spiked with 5-45 mg kg-1 Cd showed that D. pinnata has a strong Cd tolerance capacity and appreciable shoot Cd bioconcentration factors (0.80-1.32) and translocation factors (0.81-1.59), indicating that D. pinnata can be defined as a Cd accumulator. In the rhizosphere, Cd stress (45 mg kg-1 Cd) did not change the soil physicochemical properties but influenced the bacterial community composition compared to control conditions. Notably, the increased abundance of the bacterial phylum Patescibacteria and the dominance of several Cd-tolerant plant growth-promoting rhizobacteria (e.g., Sphingomonas, Gemmatimonas, Bryobacter, Flavisolibacter, Nocardioides, and Bradyrhizobium) likely facilitated Cd tolerance and accumulation in D. pinnata. Comparative transcriptomic analysis showed that Cd significantly induced (P < 0.001) the expression of genes involved in lignin synthesis in D. pinnata roots and leaves, which are likely to fix Cd2+ to the cell wall and inhibit Cd entry into the cytoplasm. Moreover, Cd induced a sophisticated signal transduction network that initiated detoxification processes in roots as well as ethylene synthesis from methionine metabolism to regulate Cd responses in leaves. This study suggests that D. pinnata can be potentially used for phytoextraction and improves our understanding of Cd-response mechanisms in plants from rhizospheric and molecular perspectives.

Effect of Plant Growth Retardants on Growth and Flowering of Dahlia (Dahlia variabilis L.) CV. Edinburgh

The present investigation was conducted in the Research Field, Department of Horticulture, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, from November 2021 to March 2022 to study the effect of plant growth retardants on the growth and flowering of dahlia (Dahlia variabilis L.) cv. Edinburgh. The seedlings were planted at a spacing of 50cm x 50cm from row to row and plant to plant to accommodate nine plants per 3- meter square area. The experiment's design used a Randomized Block Design with thirteen treatments that were duplicated three times. The plants were watered immediately after planting and at weekly intervals during the growing period. Based on the present investigation, the treatment T12 maleic hydrazide@1200ppm was found best in terms of plant growth parameters, flower, and yield of Dahlia. In terms of economics, the maximum Cost Benefit ratio (1: 2.62) was also found in treatment T12 maleic hydrazide@1200ppm, whereas the minimum Cost benefit ratio (1:1.33) was recorded in treatment T0 (Control).

Farklı kök bakterisi ve mikoriza uygulamalarının yıldız çiçeği (Dahlia variabilis) fidelerinin büyüme ve gelişimine etkileri

Amaç: Bu çalışma, bitki gelişimini teşvik eden farklı kök bakterisi ve mikoriza uygulamalarının kesme çiçek ve dış mekân süs bitkisi olarak dünya genelinde üretimi yaygın olan ve Türkiye’de de gittikçe yaygınlaşan Dahlia variabilis (Yıldız çiçeği) bitkisinde tohumdan fideye kadar geçen aşamada, büyüme ve gelişimine etkilerini belirlemek amacıyla yapılmıştır. Yöntem ve Bulgular: Çalışma kapsamında, Dahlia variabilis ‘Violet’ çeşidine ait tohumlara, Enterobacter cloacae (ZE-2), Bacillus cereus (ZE-7), Pseudomonas putida (ZE-12), Acinetobacter calcoaceticus (ZE-13), Burkholderia cepecia (7-a-2) bakteri türleri ve ticari olarak satışı bulunan mikoriza (5000 ppm) uygulanmıştır. Çalışmada, uygulamaların fide büyüme ve gelişimine etkilerini belirlemek için; çimlenme oranı (%), fide boyu (cm), gövde çapı (mm), yaprak sayısı (adet), bitki yaş ağırlığı (g), bitki kuru ağırlığı (g), kök uzunluğu (cm), kök yaş ağırlığı (g), kök kuru ağırlığı (g) ve SPAD değeri ile klorofil içeriği ölçülmüştür. Çalışma sonunda, yapılan uygulamaların Yıldız çiçeği üzerinde farklı etkilere sahip olduğu belirlenmiştir. Pseudomonas putida (ZE-12) uygulamasının kontrole kıyasla %12 oranında çimlenmeyi artırdığı, Acinetobacter calcoaceticus (ZE-13) bakterisinin fide boyunda %32.9’luk artış sağladığı belirlenmiştir. Genel Yorum: Sonuç olarak, bu çalışma ile doğal kökenli olan ve çevreye zararı olmayan bu bakterilerin süs bitkilerinde fide yetiştiriciliğinde kullanılabilme potansiyeline sahip olduğu belirlenmiş olup, süs bitkileri üretim sektöründe bu uygulamaların kullanımının yaygınlaştırılması önem arz etmektedir. Çalışmanın Önemi ve Etkisi: Dahlia bitkisi, Dünya’da tanınmasına rağmen Türkiye’de bu konuda pek fazla bilgi bulunmamaktadır. Ayrıca Dahlia bitkisinin tohumdan fide aşamasına kadar geçen sürede, daha kaliteli fideler elde etmek için yeni izole edilen bakteri türlerinin kullanımı da oldukça sınırlıdır. Bu çalışma ile sürdürülebilir yöntemler arasında yer alan bakteri ve mikoriza uygulamaları ile fide kalitesini iyileştirmek önem arz etmektedir.

Determination of Calcium Levels with XRF and Literature Review of its Bioavailability in Vitro of Dahlia Tubers Syrop (Dahlia Pinnata Cav.)

Calcium bioavailability (Ca) states the ratio of available calcium to the amount of calcium consumed during metabolic processes. The bioavailability of Ca is calculated by the difference between the amount of Ca in the consumed food product and the excreted feces. In this research, calcium can be obtained from dahlia tuber syrup (Dahlia pinnata Cav.). The purpose of this study was to discuss the determination of Ca levels and a literature review of the Ca bioavailability of dahlia tuber syrup (Dahlia pinnata Cav.) in vitro. The content of Ca in dahlia tubers was determined experimentally using an XRF (X-Ray Fluorescence) instrument. The bioavailability of Ca was determined by predicting the ratio of inulin and Ca content. The results showed that the Ca content of dahlia tuber syrup was 197,57 ppm. The bioavailability of Ca in dahlia tuber syrup in vitro was predicted from a relatively high ratio of inulin content of around 65-86% and FOS levels from hydrolysis of 5% dahlia tuber inulin about 15,41-29,38% or an average of 22,395%, on Ca levels is 81,46-85,33%. The results of the study on the bioavailability of Ca in dahlia tuber syrup (Dahlia pinnata Cav.) have a fairly high level. The high bioavailability of Ca can increase calcium absorption in the body and have health effects, among others, for heart and bone health.

A novel aldo-keto reductase gene is involved in 6'-deoxychalcone biosynthesis in dahlia (Dahlia variabilis).

A novel gene belonging to the aldo-keto reductase 13 family is involved in isoliquiritigenin biosynthesis in dahlia. The yellow pigments of dahlia flowers are derived from 6'-deoxychalcones, which are synthesized via a two-step process, involving the conversion of 3-malonyl-CoA and 4-coumaloyl-CoA into isoliquiritigenin in the first step, and the subsequent generation of butein from isoliquiritigenin. The first step reaction is catalyzed by chalcone synthase (CHS) and aldo-keto reductase (AKR). AKR has been implicated in the isoflavone biosynthesis in legumes, however, isolation of butein biosynthesis related AKR members are yet to be reported. A comparative RNA-seq analysis between two dahlia cultivars, 'Shukuhai' and its butein-deficient lateral mutant 'Rinka', was used in this study to identify a novel AKR gene involved in 6'-deoxychalcone biosynthesis. DvAKR1 encoded a AKR 13 sub-family protein with significant differential expression levels, and was phylogenetically distinct from the chalcone reductases, which belongs to the AKR 4A sub-family in legumes. DNA sequence variation and expression profiles of DvAKR1 gene were correlated with 6'-deoxychalcone accumulation in the tested dahlia cultivars. A single over-expression analysis of DvAKR1 was not sufficient to initiate the accumulation of isoliquiritigenin in tobacco, in contrast, its co-overexpression with a chalcone 4'-O-glucosyltransferase (Am4'CGT) from Antirrhinum majus and a MYB transcription factor, CaMYBA from Capsicum annuum successfully induced isoliquiritigenin accumulation. In addition, DvAKR1 homologous gene expression was detected in Coreopsideae species accumulating 6'-deoxychalcone, but not in Asteraceae species lacking 6'-deoxychalcone production. These results not only demonstrate the involvement of DvAKR1 in the biosynthesis of 6'-deoxychalcone in dahlia, but also show that 6'-deoxychalcone occurrence in Coreopsideae species developed evolutionarily independent from legume species.

A foliar spray application of indole-3-butyric acid promotes rooting of herbaceous annual cuttings similarly or better than a basal dip

Foliar rooting hormone applications containing indole-3-butyric acid (IBA) to unrooted vegetative cuttings have gained popularity as they reduce labor costs and the risk of spreading diseases compared to standard basal dips. The objective of this study was to quantify if foliar applied 20% IBA promotes adventitious rooting of herbaceous annuals similarly to a basal dip application of IBA + 1-napthaleneacetic acid (NAA). Dahlia (Dahlia pinnata) Venti™ ‘Passion Fruit’, osteospermum (Osteospermum ecklonis) Serenity™ ‘Lavender Frost’, scaevola (Scaevola aemula) Scalora® ‘Brilliant’ and geranium (Pelargonium × hortorum) Sunrise™ ‘Lavender + Red Eye’ cuttings received a foliar spray of 0, 150, 300, or 600 mg·L–1 IBA at 0.2 L·m–2; 150 or 300 mg·L–1 IBA at 0.8 L·m–2; or a basal dip of 100 mg·L–1 + 50 mg·L–1 or 200 mg·L–1 + 100 mg·L–1 IBA + NAA. In most cases, cuttings receiving a foliar application of 300 mg·L–1 IBA at 0.8 L·m–2 had either comparable or greater root dry mass than cuttings receiving a basal dip of IBA + NAA and outperformed the control. After 14 d, root dry mass was generally greatest when cutting were treated with 300 mg·L–1 IBA at 0.8 L·m–2 and was an equal or better alternative to a basal dip. For the most effective results, rooting hormones should be utilized when the DLI integral is <12 mol·m–2·d–1.

Mites and insects occurring on some leafy ornamentals and floricultural plants in Howrah and Purba Medinipur districts of West Bengal, with their economic importance

The present paper deals with a total of 26 species of mites under 10 families, 17 genera and 3 orders as well as 10 species of insects under 5 families, 9 genera and 3 orders, collected from some floricultural and leafy ornamental plants in Howrah and Purba Medinipur districts of West Bengal. It may be mentioned here that these two districts are the largest producers of these plants. Among the mites, there are 14 species under 4 families and 8 genera which belong to phytophagous group, 10 species under 4 families and 7 genera belong to predatory group and remaining 2 species under as many families and genera belong to fungal feeding group. All the species of mites and insects are listed with their respective host/habitat plants, collection localities as well as their economic importance, if any. The most injurious species of mites which were observed in the field are Tetranychus urticae on Dahlia variabilis, Oligonychus biharensis on Rosa centifolia, Eutetranychus orientalis on Tabernaemontana divaricata and, Eotetranychus suginamensis on Nyctanthes arbor-tristis. Among the predatory mites, Amblyseius largoensis and Amblyseius herbicolus are important predators on phytophagous mites and the occurrence of the other predatory mites are only occasional. Among the insects, Ferrisia virgata, Aphis gossypii and Scirothrips sp. on Codiaeum variegatum, and Ferrisia virgata on Hibiscus rosa-sinensis, respectively were found abundantly.

First purified recombinant CYP75B including transmembrane helix with unexpected high substrate specificity to (2R)-naringenin

Anthochlor pigments (chalcones and aurones) play an important role in yellow flower colourization, the formation of UV-honey guides and show numerous health benefits. The B-ring hydroxylation of chalcones is performed by membrane bound cytochrome P450 enzymes. It was assumed that usual flavonoid 3′-hydroxlases (F3′Hs) are responsible for the 3,4- dihydroxy pattern of chalcones, however, we previously showed that a specialized F3′H, namely chalcone 3-hydroxylase (CH3H), is necessary for the hydroxylation of chalcones. In this study, a sequence encoding membrane bound CH3H from Dahlia variabilis was recombinantly expressed in yeast and a purification procedure was developed. The optimized purification procedure led to an overall recovery of 30% recombinant DvCH3H with a purity of more than 84%. The enzyme was biochemically characterized with regard to its kinetic parameters on various substrates, including racemic naringenin, as well as its enantiomers (2S)-, and (2R)-naringenin, apigenin and kaempferol. We report for the first time the characterization of a purified Cytochrome P450 enzyme from the flavonoid biosynthesis pathway, including the transmembrane helix. Further, we show for the first time that recombinant DvCH3H displays a higher affinity for (2R)-naringenin than for (2S)-naringenin, although (2R)-flavanones are not naturally formed by chalcone isomerase.

Genetic Divergence Analysis of Dahlia (Dahlia variabilis L.) Genotypes

The present investigation was carried out to assess the extent of genetic variability, heritability, genetic advance and genetic divergence using 35 dahlia (Dahlia variabilis L.) genotypes with 20 characters. Moderate to high GCV and PCV were recorded for almost all the characters under study emphasizing the existence of variation in the population. All the characters (except plant spread and width of the tuber) showed high heritability along with higher or moderate genotypic coefficient of variation and genetic advance indicating that most likely the heritability was due to additive gene effects and the genotypes under study were highly diverse. The inter-cluster average D2 value was maximum between the cluster V and III (D2=6704.46) and minimum inter cluster distance was obtained between cluster IV and I (D2 =1256.64).

Studies on Component Characters Association with Flower Yield of Dahlia (Dahlia variabilis L.) Genotypes

Thirty five genotypes of dahlia (Dahlia variabilis L.) were studied for fifteen different growth, flowering, quality and yield traits for the association of different characters with flower yield per plant (g). The results indicated a significant and desirable correlation between flower yield per plant with the characters like number of secondary branches per plant, number of leaves, leaf area, duration of the crop, flower diameter, number of petals per flower, stalk length, individual flower weight, number of flowers per plant, number of tubers per plant at genotypic and phenotypic level respectively.. This provides a knowledge regarding association of various characters among themselves and to estimate the inherent association between genes.

Performance of dahlia (Dahlia variabilis L.) genotypes for floral and yield attributes

The experiment on “Performance of dahlia (Dahlia variabilis L.) genotypes for floral and yield attributes” was carried out at the Department of Floriculture and Landscape Architecture, College of Horticulture, Sirsi, University of Horticultural Sciences, Bagalkot, Karnataka with a view to find out the best genotypes for floral and yield characters. Among 35 genotypes HUBD-26 recorded minimum days to flowering (31.40 days), maximum flower yield per plant (559.03 g) and flower yield per hectare (207.05 q). Whereas Genotype HUBD-21 recorded longest duration of flowering (84.80 days) and HUBD-30 (13.52 cm) showed highest flower diameter. The number of petals per flower was recorded maximum (104.30) in genotype HUBD-25.