Canna Cultivars Research Articles

Molecular characterization of Canna yellow streak virus with divergent coat protein N-terminal fragment in Iraq.

Canna yellow streak virus (CaYSV,familyPotyviridae)infects many canna cultivars, which have been widely cultivated in the Iraqi gardens for ornamental purposes. The genetic variability within multiple genomic regions of CaYSV population has been demonstrated in the 3' part, particularly in the coat protein (CP). This work was aimed to characterize CaYSV and investigate its variability from canna plants in Iraq. Leaves of canna plants grown in severalgardens in Baghdad were tested by potyvirus group antibodies and RT-PCR. Analysis of the nucleotide (nt) sequences corresponding to the 3' part of the virus genomerevealed the highest identity (81.6-90.6%) with known CaYSV isolates. Phylogenetic analysis of the coat protein (CP) genesequence placed the Iraqiisolates in a separate clade with members of group A. This distinction was evidenced by unique amino acid changes found within the N-terminal motif of the CP. This is the first report of phylogenetically distinct CaYSV in Iraq. This is the first report of phylogenetically distinct CaYSV with divergent CP N-terminus in Iraq.

Comprehensive evaluation of waterlogging tolerance of eleven Canna cultivars at flowering stage

To identify and screen the waterlogging-tolerant cultivars of Canna spp. and establish a comprehensive, mathematical evaluation model of Canna plants, morphological characteristics and physiological indices were recorded and measured using the leaves of 11 cultivars. Their waterlogging tolerance was overall evaluated by calculating the waterlogging injury index (WII) and waterlogging tolerance coefficient (WTC) based on the morphological traits and physiological indices. Results revealed that after waterlogging stress, adventitious roots appeared in all cultivars, whose length and number increased as the stress persisted. Among the tested species, there were more adventitious roots observed in C. edulis Ker, C. waracewiezii Dietr. and C. orchioides Bailey., while C. indica L., C. flaccida Salisb., and C. generalis Bailey. had few adventitious roots. Additionally, the edges of the lower leaves of C. edulis Ker. cv. ‘PLRF’, ‘Xingyu-1′, ‘Xingyu-2′ and C. orchioides Bailey. cv. ‘Sajin’ yellowed the most and experienced the worst scorch. Damage was less obvious on C. generalis Bailey. cv. ‘Mohong’ leaves after waterlogging stress for 21 d Furthermore, ‘Mohong’ was determined to be the most waterlogging tolerant cultivar and had the lowest WII value (0.400), while the ‘PLRF’ had the highest (0.840) and clustered into the waterlogging-sensitive group. Four physiological indices, including catalase (CAT), peroxidase (POD), soluble sugar (SS) and malonaldehyde (MDA) increased (WTC > 1) after waterlogging, while soluble protein (SP) decreased (WTC < 1) in all cultivars. Changes in the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX) differed among cultivars. Principal component analysis (PCA) transformed the 7 physiological indices into 4 independent, comprehensive indices, whose cumulative contribution ratio reached 96.062%. The 11 cultivars were divided into 4 categories based on the comprehensive evaluation value (D). ‘Mohong’, in the waterlogging-tolerant group had the highest D value (0.912). C. waracewiezii Dietr. cv. ‘Ziye Xiaojuhong’, C. generalis Bailey. cv. ‘Grand Due’, C. orchioides Bailey. cv. ‘Suihua Chenghong’ and C. indica L. belonged to the intermediate waterlogging-tolerant group with D values of 0.652, 0.616, 0.590 and 0.533, respectively. C. orchioides Bailey. cv. ‘Lüyecheng’, C. flaccida Salisb. cv. ‘Yellow Canna’, ‘Xingyu-1′ and ‘Xingyu-2′ were clustered into the low waterlogging-tolerant group with the D values of 0.458, 0.455, 0.421 and 0.368, respectively. Lastly, ‘Sajin’ and ‘PLRF’ clustered into the sensitive waterlogging tolerant group with the lowest D value of 0.201 and 0.170, respectively. The stepwise regression analysis showed that CAT, POD, SOD, APX, SS and MDA, can be used to evaluate and predict the waterlogging tolerance of different Canna lily cultivars.

Accumulation dynamics and physicochemical variability of starch in cultivars of Canna edulis Ker

ABSTRACT Canna edulis, also known as achira or sagu, is widely grown in South America because its rhizomes are a major source of starch for food and agroindustry. This study aimed to assess the accumulation rate and physicochemical changes of starch from four canna cultivars (Verde, Nativa, Maituna and Morada), grown under a traditional system, in the southwest region of Colombia. The rhizomes were harvested after planting (between five and nine months) to extract and characterize the starch. It was found that the starch yield (% wb) was related to the plant development age, reaching a maximum at eight months for all cultivars (12.78 ± 0.19 % - Verde; 12.46 ± 0.18 % - Maituna; 12.17 ± 0.19 % - Nativa; 11.10 ± 0.18 % - Morada). The average chemical composition (% wb) of the native starch throughout the rhizome development, for all cultivars, was: 86.68 % of starch, 1.12 % of protein, 0.43 % of dietary fiber, 0.14 % of ash and 11.57 % of moisture. At the optimum harvest age, the minimum and maximum amylose contents were 45.63 % (Maituna) and 54.47 % (Verde). The starch granule size among the cultivars showed a normal distribution, with a range of 40 µm to 80 µm and mean of 59.9 µm. The pasting curves per cultivar showed that the starch generated very high viscosity gels, unstable to the heating-cooling cycles, and high retrogradation.

THE EFFECT OF FUNGAL ACTIVITY ON PHOTOSYNTHETIC PARAMETERS OF DIFFERENT CANNA CULTIVARS UNDER FIELD CONDITIONS

Three-year studies (2014–2016) were conducted in Lublin in the south-east Poland. The objects of research were the plants of ten canna cultivars: ‘Aida’, ‘America’, ‘Botanica’, ‘Cherry Red’, ‘La Boheme’, ‘Lucifer’, ‘Picasso’, ‘Robert Kemp’, ‘President’ and ‘Wyoming’. Observations were carried out each year in October. Plants with symptoms of stem and root rot, leaves yellowing and wilt were noticed on the investigated plantations. The plants were studied with regard to photosynthetic activity and also by disease index for all cultivars and statistical analysis was carried out upon them. The effect of disease index on photosynthetic intensity and transpiration was determined after the calculation of Pearson’s correlation coefficient. Infected plants were collected for mycological analysis. The results of mycological analysis showed that canna plants were colonized by Fusarium spp., Sclerotinia spp. and Alternaria spp. Alternaria alternata, Fusarium oxysporum, Fusarium avenaceum and Sclerotinia sclerotiorum predominated among pathogenic species. The best health status and the lowest number of colonies were noticed for plants of cv. ‘Botanica’. The infection of canna leaves by pathogenic fungi has negatively affected the intensity of photosynthesis, transpiration, stomatal conductance and sub-stomatal CO2 concentration and it was largely related to the degree of infestation of specified varieties of canna. The photosynthesis process was limited especially in ‘La Boheme’, ‘Picasso’, ‘Cherry Red’ and ‘President’ cultivars, which were infected most frequently by pathogenic fungi. It was confirmed by negative Pearson’s coefficient.

Arsenic accumulation in Canna: Effect on antioxidative defense system

Three Canna cultivars namely Canna red dazzler (CR), Canna flaccida (CF) and Canna cala lillies (CL) were selected to examine the uptake of arsenic and antioxidative response at four different arsenic concentrations (10, 20, 30 and 50 mg kg¯1). The study consisted of three harvestings at an interval of 45 days each, and at each harvest arsenic uptake and antioxidant activity were examined. The arsenic uptake and antioxidant activity were more in roots as compared to shoots. The percentage uptake of arsenate by CL, CF and CR at 10, 20, 30 and 50 mg kg¯1 were 52, 43, 36, 35 for CL, 39, 40, 35, 34 for CF and 45, 41, 37, 33 for CR respectively. The antioxidant enzymatic activity was higher in CL and CR than CF cultivar. The overall enzymatic antioxidants had their activities increased from first to second harvesting and were significantly higher in the third harvesting in all the three varieties as compared to control. Results suggested that Canna cultivars can be a better option for rhizofiltration or phytostabilization rather than phytoextraction and as it has an effective antioxidative mechanism in reducing the arsenic stress.

Low-cost shoot multiplication and improved growth in different cultivars of Canna indica.

Canna (Canna indica L.) is an ornamental landscape plant used specially for the garden borders and beds. It grows in tropical and subtropical countries including India. Canna is a less explored crop, mainly because it is a slow growing monocot with extremely hard seed coat and difficult to establish in vitro, as bacterial contamination is carried through the soil-grown rhizome. Many cultivars (ca. 150) of canna are being maintained in the garden germplasm of National Botanical Research Institute. To obtain 100% in vitro seed germination, chipping off of seeds with a sterilized nail clipper and soaking for 24-48h or until radical emergence was a prerequisite. To obtain a foolproof tissue culture protocol of canna, in the present study, shoot multiplication was obtained through rhizome axillary buds. Among semisolid, liquid submerged and liquid media with glass beads, the highest multiplication of shoots (10) was obtained in liquid media with glass beads in 'Canna Flaccida' cv. within 6weeks of culture incubation. During a comparative analysis of shoot regeneration among ten most attractive selected cultivars of canna, two did not respond, whereas a significant difference was obtained among eight cultivars. The regenerated shoots were rooted, acclimatized, and transferred to the pots, where they grew normally.

Global gene expression and pigment analysis of two contrasting flower color cultivars of Canna

Development of flower color in plants is a complex process. Among others, it is an important trait for ornamental flowering plants. Canna is a flowering ornamental plant of family Cannaceae. To understand the molecular mechanism of flower color development in Canna, RNA sequencing from flower tissues of two contrasting flower color cultivars, Red President (RP) and Tropical Sunrise (TS) was performed. More than 27.0 million and 19.0 million clean reads were obtained from RP and TS, respectively. The combined clean reads were assembled into 147,295 unigenes. The Canna unigenes showed maximum homology with Populus trichocarpa (26.79%). A total of 2702 unigenes expressed differentially between the two cultivars of which 1972 were up-regulated and 730 were down-regulated in RP. Phenylpropanoid and flavonoid biosynthetic processes were the significant processes in RP. Expression of a vast number of transcription factors including MYB, bHLH, ARF, and WRKY were higher in RP than TS. The expression analysis of RNA sequencing data was validated by qRT-PCR analysis. Further, concentration of measured anthocyanidins and flavonols were very low or absent in TS, corroborating largely with our transcriptome data. These findings may help in understanding flower color development in Canna and in future crop breeding program.

Molecular characterization of viruses infecting canna in Russia

Canna yellow streak virus (CaYSV), Canna yellow mottle virus (CaYMV), Bean yellow mosaic virus (BYMV), and Cucumber mosaic virus (CMV) were detected by reverse transcription-polymerase chain reaction in 16 local and introduced canna cultivars grown in the collection of the Nikita Botanical Gardens, Crimea. CaYSV was detected in all the cultivars tested, and most of the cultivars had mixed infection with two or three viruses. Analysis of the 3′-terminal genomic sequences revealed a high degree of diversity among isolates of CaYSV and BYMV suggesting their multiple introductions in the Gardens. Phylogenetic analysis of the coat protein (CP) gene showed that all the Crimean BYMV isolates together with the Chinese and the Indian ones from canna formed a separate cluster of canna-adapted isolates. Unique amino acid substitutions at positions 58, 70, 106, 168 and 215 of the CP were found in all isolates from canna that may be relevant to the adaptation of BYMV to this host. The sequences of the CaYMV isolates were highly conserved. The sequence identities of their ORF3 genomic segment ranged from 98.7–100% and from 97.7–100% at the nucleotide and amino acid levels, respectively. The CMV isolate was most closely related to the isolate Fny (D10538) from muskmelon. This is the first report of CaYSV, CaYMV, BYMV and CMV on canna in Russia confirming their worldwide distribution on this culture.

Identification and Expression Analyses of miRNAs from Two Contrasting Flower Color Cultivars of Canna by Deep Sequencing

miRNAs are endogenous small RNA (sRNA) that play critical roles in plant development processes. Canna is an ornamental plant belonging to family Cannaceae. Here, we report for the first time the identification and differential expression of miRNAs in two contrasting flower color cultivars of Canna, Tropical sunrise and Red president. A total of 313 known miRNAs belonging to 78 miRNA families were identified from both the cultivars. Thirty one miRNAs (17 miRNA families) were specific to Tropical sunrise and 43 miRNAs (10 miRNA families) were specific to Red president. Thirty two and 18 putative new miRNAs were identified from Tropical sunrise and Red president, respectively. One hundred and nine miRNAs were differentially expressed in the two cultivars targeting 1343 genes. Among these, 16 miRNAs families targeting60 genes were involved in flower development related traits and five miRNA families targeting five genes were involved in phenyl propanoid and pigment metabolic processes. We further validated the expression analysis of a few miRNA and their target genes by qRT-PCR. Transcription factors were the major miRNA targets identified. Target validation of a few randomly selected miRNAs by RLM-RACE was performed but was successful with only miR162. These findings will help in understanding flower development processes, particularly the color development in Canna.

不同栽培方式对美人蕉生长发育及生理特性的影响

本文比较了盆栽、水培和地栽三种不同栽培条件对5种不同美人蕉植株生长发育和生理特性的差异。结果表明，地栽方式有利于根系尤其是主根的伸长，水培有利于美人蕉侧根以及毛细根数量的增加和根系表面积的增大，后者对于植物养分吸收与生长发育更为有效。水培条件还对美人蕉的植株有一定的矮化作用，使其根冠比增大。测定不同品种在水培和地栽条件下基于叶绿素荧光参数的光合速率无明显差异，而5种美人蕉在盆栽条件下的光合效率、生长速率均最低。因此，美人蕉极具水培花卉的潜质。 The cultivation experiments were conducted to study the differences in potted culture, hydroponics and soil culture on the growth development and physiological traits on five Canna cultivars. The results showed that soil culture was conductive to roots growth, especially the taproot of Cannas. In contrast, hydroponics could increase quantity of lateral roots and capillary root and magnify root cap area. The latter could facilitate nutrient uptake and growth development of plants. Meanwhile, hydroponics could dwarf Canna plants and increase the root cap ratio. Expressed by fluorescence parameters, photosynthetic efficiency of Canna plants had no significant difference between the hydroponics treatment and the soil culture treatment. Five Canna cultivars by potted culture had the lowest level of photosynthetic efficiency and growth rate. Thus, Canna could be used as hydroponic ornamental flowers.

ОСОБЕННОСТИ КЛОНАЛЬНОГО МИКРОРАЗМНОЖЕНИЯ КАННЫ САДОВОЙ (Canna × Hybrida hort.)

Regenerants of Canna ( Canna  hybrida hort. ) cvs. Suevia, Dar Vostoka and Livadia have been obtained. Dependence of viability and regenerative capacity of Canna microshoots on genotype has been found. The optimal concentrations of growth regulators that influence on morphogenesis in vitro have been determined. At the micropropagation stage of different cultivars of Canna it needs the addition of 1.24-1.91 mg/l thidiazuron to culture medium. The active rooting of Canna microshoots cvs. Dar Vostoka and Suevia on the culture medium Murashige & Skoog and Pierik with auxins -indol3-acetic acid and -naphthylacetic acid have been observed. The ability of Canna cv. Suevia micro-shoots to spontaneous root formation has been shown. The formation of meristemoids in culture in vitro of Canna explants have been confirmed by the results of histological investigations.

First report of Canna yellow mottle virus on Canna from India

Canna (Canna indica) is a popular landscape plant known for its attractive foliage and flowers and is grown in tropical and subtropical countries including India. Various cultivars of canna are being maintained as germplasm at the Botanic Garden, NBRI, Lucknow. During a survey in September 2012, necrotic striping, severe veinal chlorosis, yellow mosaic and veinal streaking symptoms were observed on the leaves of different canna cultivars (Fig. 1a-d), with the disease incidence between 17 and 35% at NBRI. Subsequently, similar symptoms were found on canna in other gardens in Lucknow. Symptoms observed were similar to those described previously for canna yellow mottle disease and associated with Canna yellow mottle virus (CaYMV) (Pappu et al., 2008; Marino et al., 2008). For virus detection, total genomic DNA was isolated from leaf samples of 13 plants with symptoms and one without, and subjected to PCR using CaYMV specific primers (CaYMV-3 and CaYMV-4; Momol et al., 2004). PCR resulted in an amplicon of the expected size (~550 bp) in all the 13 samples with symptoms, but not in the sample from the symptomless plant, indicating the presence of CaYMV in the diseased plants. Subsequently the 13 amplicons obtained from 10 different cultivars of Canna indica and C. flaccida were cloned, sequenced and deposited in GenBank (Table 1). These accessions, in BLASTn analysis, were shown to share 93-99% nucleotide sequence identity with the available CaYMV isolate sequences from around the world. Further, phylogenetic analysis of sequences under study by MEGA5.1 (Tamura et al., 2011) using a neighbour-joining method clearly clustered them together with CaYMV (Fig. 2). Based on sequence comparison and phylogenetic analysis, the virus isolates in this study were identified as CaYMV. To the best of our knowledge, this is the first report of natural occurrence of CaYMV on canna from India. CaYMV may be considered as posing a phytosanitary risk for further spread in canna since it is being propagated through suckers or rhizomes.

Production of discernible disease phenotypes in Canna by five plant viruses belonging to the genera Potyvirus,Cucumovirus and Badnavirus

Cannas are tropical and subtropical flowering perennial plants. The genus contains many species but most commercially grown cultivars are interspecific hybrids selected for their attractive foliage and flowers. Canna production is so lucrative that there are farmers and nurseries dedicated solely to its production. The specific issue that the canna industry faces is virus diseases. In this study, rhizomes of 24 canna cultivars were gathered and diagnostics conducted to detect Bean yellow mosaic virus (BYMV, Potyvirus), Canna yellow mottle virus (CaYMV, Badnavirus), Canna yellow streak virus (CaYSV, Potyvirus), Cucumber mosaic virus (CMV, Cucumovirus) and Tomato aspermy virus (TAV, Cucumovirus). Visual assessment of disease symptoms and diagnostic tests were carried out to identify the prevalent diseases and describe the symptoms that are associated with virus infection. BYMV, CaYMV and CaYSV caused severe mosaic and necrosis either in the leaf lamina or veins of infected leaves. Potyvirus infection suppressed red colouration in the foliage of some varieties. CaYMV and CaYSV often appeared in the same plant, suggesting they might represent a viral complex. CMV and TAV were rarely seen in these populations. Interestingly, CaYMV but not CaYSV could be mechanically inoculated to Phaseolus vulgaris plants.

AFLP based genetic relationship and population structure analysis of Canna—An ornamental plant

Genetic relationships among 42 cultivars of Canna were determined by using amplified fragment length polymorphism (AFLP) marker. A total of 1607 DNA fragments was produced with 25 AFLP primer combinations and out of which 1491 (92.78%) were found polymorphic and 116 (7.22%) monomorphic. The number of polymorphic fragments varied from 33 (E-ACA/M-CAA) to 86 (E-ACT/M-CAA) with an average of 59.6 per primer combination and percent polymorphism varied from 81.7% (E-AAG/M-CAA) to 100% (E-ACC/M-CTT) with an average of 92.8% per primer combination. The polymorphism information content (PIC) value ranged from 0.24 to 0.35 with an average of 0.30 per fragment and the highest PIC value (0.35) was noticed for primer combination E-AAG/M-CAC followed by E-ACT/M-CTA, E-ACA/M-CAA, E-AAG/M-CAA (0.34). Marker index (MI) and resolving power (RP) varied from 11.22 to 26.66 and 17.10 to 40.00 respectively. Jaccard's similarity coefficient varied from 0.33 to 0.72 with an average of 0.49±0.03. The maximum genetic similarities (72%) were noticed between the cultivar NBC_1 and NBC_2; NBC_16 and NBC_19 followed by NBC_19 and NBC_30 (70%). Based upon genetic similarity coefficient the cultivars NBC_43, NBC_24, NBC_38, NBC_22, NBC_29 and NBC_36 were found to be most divergent among all the cultivars. The UPGMA clustering revealed four major groups accommodating 93% cultivars and three cultivars each of different species i.e. C. argentina (NBC_24), C. latifolia (NBC_43) and C. generalis (NBC_13) did not grouped with any clusters. Model based clustering obtained from STRUCTURE analysis also reveals similar pattern of grouping.

Oxidative stress and non-enzymatic antioxidants in leaves of three edible canna cultivars under drought stress

The physiological responses of three edible canna cultivars (Canna edulis ker. cv. ‘PLRF’, ‘Xingyu-1’, and ‘Xingyu-2’) to continuous drought stress for 35 days were investigated by characterizing the water saturation deficit (WSD), relative electrical conductivity (REC), superoxidative radical content (SRC), ascorbic acid (AsA) content, glutathione (GSH) content and protein content. It was observed that WSD, REC, SRC progressively increased in the upper leaves of three cultivars under both control and drought treatments. The content changes of AsA, GSH and water soluble protein were lower in ‘Xingyu-2’ than in ‘Xingyu-1’ and ‘PLRF’, in upper leaves than in lower leaves. Compared with control, drought stress aggravated these physiological changes in all three cultivars. The correlation analysis showed that there were significant correlations between indexes except for protein content, which significantly correlated only with SRC. These indicated that drought stress directly led to water loss, and then the REC increased, while the GSH and AsA played major roles in removing the SRC. These results revealed that ‘Xingyu-2’ was more tolerant to drought stress than ‘PLRF’ and ‘Xingyu-1’ and the lower leaves were more sensitive than the upper leaves. The present study not only provides new insights into mechanisms of acclimation and tolerance to drought stress in edible canna but also provides clues for improving drought tolerance of edible canna through breeding or genetic engineering.

Free radical scavenging activity of ornamental and edible cultivars of Canna found in Eastern India

Canna, the only genus of family Cannaceae, found in eastern India have gained economic importance for their starchy rhizomes and attractive flowers. The rhizome of some edible cultivars are consumed as food and herbal medicines in rural areas. The presence of total phenols, flavonoids and DPPH scavenging activity of both cold and hot extracts and their correlations have been studied for eleven cultivars of Canna spp. Antioxidants, quercetin and gallic acid equivalence of phenolic compounds were determined spectrophotometrically. It has been found that total phenol, flavonoids and DPPH free radical scavenging activity were higher in hot extracts than in cold. Further studies gave an idea about the correlation between phenol and flavonoid contents of both cold and hot extracts, but both the above said parameters were not correlated with DPPH scavenging activity. Finally it can be concluded that higher DPPH scavenging activities in all these Canna cultivars may not be due to the presence of endogenous phenols and flavonoids but these may be due to any other phytochemicals.

Characteristics of Clear Noodles Prepared from Edible Canna Starches

ABSTRACT: Clear noodles were prepared from starches of 3 edible canna cultivars namely; Thai‐purple, Thaigreen, and Japanese‐green. The effects of amount of gelatinized starch, moisture content of dough, and holding temperature after cooking on noodle appearance were investigated. Ten percent gelatinized starch, 55% moisture content, and holding temperature at 4°C for 24 h gave clear noodles with appearance, cooking loss, and rehydration ratio comparable to commercial mung bean noodles. However, the canna noodles were of inferior tensile strength. Moisture content of the canna noodles was 15.24% to 15.46%. Their chemical compositions on dry weight basis were as follows: 89.41% to 91.63% starch, 0.21% to 0.33% protein, &gt; 0.01% lipid, 0.16% to 0.20% ash. Measured diameters of noodles were in the range of 0.73 to 0.88 mm. The cooking losses were 0.93% to 0.55% dry weight, whereas tensile stresses were 17.44 to 22.77 g/mm2. The energy values derived from 100 g of canna noodles were 358.48 to 367.84 kcal. Sensory evaluation by descriptive test revealed that there were no significant differences (P ≤ 0.05) in the general acceptability between the canna noodles and the commercial mung bean noodles. By paired‐comparison test, however, the commercial mung bean noodle A was more favorable.

A comparative study of edible canna ( Canna edulis) starch from different cultivars. Part I. Chemical composition and physicochemical properties

The chemical composition and physicochemical properties of starches isolated from three cultivars (Japanese-green, Thai-green and Thai-purple) of edible canna rhizomes were studied. Scanning electron microscopy investigations showed that the starch granules from all cultivars of canna were oval-shaped granules with smooth surfaces and were around 10–100 μm in sizes. Proximate composition studies showed that the protein content in the canna samples varied between 0.069 and 0.078%, lipid between 0.014 and 0.019% and ash between 0.25 and 0.33%. All canna starches contained considerably high phosphorus (371–399 ppm), followed by calcium (113–154 ppm) and potassium (35–61 ppm). The absolute amylose content ranged from 19 to 25%. All three starches displayed a B-type X-ray diffraction pattern. The viscograms of canna starches determined by Rapid Visco Analyzer showed that Thai-green and Japanese-green starches paste were quite stable during cooking and had high setback. The enthalpy for gelatinization and dissociation of retrograded canna starches, investigated using differential scanning calorimeter, were 17.6–18.4 and 12.3–15.0 J/g of starch, respectively. The results obtained from freeze-thaw stability and light transmittance measurements indicated that all canna starches had a high tendency for retrogradation.

Resistance of Canna Cultivars to Canna Rust and Hippeastrum Mosaic

Abstract Fifty-two cultivars of cannas (Canna X generalis L.H. Bailey and C. indica L.) were evaluated in a field planting for relative susceptibility to Hippeastrum mosaic (HM), a disease caused by Hippeastrum mosaic virus. The cultivars ‘Mrs. Pierre S. DuPont’ and ‘Pink Gem’ were the most susceptible to HM, while 2 red-leaved cultivars, ‘Wyoming’ and ‘Ambassador’, were highly resistant. Thirty-eight cultivars of cannas grown in containers were evaluated for susceptibility to canna rust (Puccinia thaliae Dietel). The cultivars ‘Halloween’ and ‘Yellow King Humbert’ were highly susceptible to rust, while the most resistant cultivars, ‘Louis Cayeaux’ and ‘La Boheme’, were still moderately susceptible. No single cultivar exhibited good resistance to both HM and rust.