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Zhanao Deng - One of the best experts on this subject based on the ideXlab platform.
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morphological cytological and molecular marker analyses of tapestry Caladium variants reveal diverse genetic changes and enable association of leaf coloration pattern loci with molecular markers
Plant Cell Tissue and Organ Culture, 2020Co-Authors: Zhe Cao, Zhanao DengAbstract:Somaclonal variation and induced mutation are highly valuable sources of genetic variation for genetic improvement and research in horticultural crops; cellular and molecular characterization can greatly facilitate their uses in these areas. In the present study, 20 Caladium variants were identified among ‘Tapestry’ plants that were regenerated from leaf cultures treated with or without colchicine. These variants showed changes in leaf main vein color and coloration pattern and were separated into ten groups based on leaf morphological changes. Five variants contained 3.3–9.7% more nuclear DNA than the wildtype and gained one, two or three chromosomes, while four variants contained 3.0–4.8% less nuclear DNA and lost one chromosome. Five, out of 22, simple sequence repeat-based molecular markers detected DNA banding pattern changes in 13 of the 20 variants. Two molecular markers (CaM24 and CaM62) detected DNA banding pattern changes in the same four variants, suggesting that these two markers may be located in the same chromosomal segment. Strong association between leaf characteristics (leaf blotching and main vein color) and molecular banding pattern changes with molecular marker CaM42 were observed in six variants, indicating that CaM42 may be associated with gene loci controlling leaf blotching and leaf main vein color in Caladium. Detailed characterization of ‘Tapestry’ Caladium variants revealed changes in nuclear DNA content, chromosome number and molecular marker banding pattern and associated gene loci controlling leaf characters with molecular markers.
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Morphological, cytological and molecular marker analyses of ‘Tapestry’ Caladium variants reveal diverse genetic changes and enable association of leaf coloration pattern loci with molecular markers
Plant Cell Tissue and Organ Culture (PCTOC), 2020Co-Authors: Zhanao DengAbstract:Somaclonal variation and induced mutation are highly valuable sources of genetic variation for genetic improvement and research in horticultural crops; cellular and molecular characterization can greatly facilitate their uses in these areas. In the present study, 20 Caladium variants were identified among ‘Tapestry’ plants that were regenerated from leaf cultures treated with or without colchicine. These variants showed changes in leaf main vein color and coloration pattern and were separated into ten groups based on leaf morphological changes. Five variants contained 3.3–9.7% more nuclear DNA than the wildtype and gained one, two or three chromosomes, while four variants contained 3.0–4.8% less nuclear DNA and lost one chromosome. Five, out of 22, simple sequence repeat-based molecular markers detected DNA banding pattern changes in 13 of the 20 variants. Two molecular markers (CaM24 and CaM62) detected DNA banding pattern changes in the same four variants, suggesting that these two markers may be located in the same chromosomal segment. Strong association between leaf characteristics (leaf blotching and main vein color) and molecular banding pattern changes with molecular marker CaM42 were observed in six variants, indicating that CaM42 may be associated with gene loci controlling leaf blotching and leaf main vein color in Caladium. Detailed characterization of ‘Tapestry’ Caladium variants revealed changes in nuclear DNA content, chromosome number and molecular marker banding pattern and associated gene loci controlling leaf characters with molecular markers.
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Caladium Cultivars ‘Cosmic Delight’, ‘Fiesta’ and ‘Hearts Desire’
EDIS, 2017Co-Authors: Zhanao DengAbstract:Caladiums are commonly grown in containers, hanging baskets or planted directly in the landscape as accent and border plants. Florida growers supply the majority of the Caladium tubers used throughout the United States and around the world. The University of Florida’s Institute of Food and Agricultural Sciences (UF/IFAS) has maintained a Caladium breeding program at the Gulf Coast Research and Education Center (GCREC). This program released three new Caladium cultivars, ‘Cosmic Delight’, ‘Fiesta’, and ‘Hearts Desire’, in 2015. This publication describes the origin and plant characteristics of these new cultivars, their tuber yield potential in production trials, and plant performances in container and landscape trials. These new cultivar introductions will be valuable to the Florida Caladium tuber-production industry, the greenhouse/nursery industries, and commercial landscape maintenance companies.
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De Novo Assembly, Annotation, and Characterization of Root Transcriptomes of Three Caladium Cultivars with a Focus on Necrotrophic Pathogen Resistance/Defense-Related Genes.
International journal of molecular sciences, 2017Co-Authors: Zhe Cao, Zhanao DengAbstract:Roots are vital to plant survival and crop yield, yet few efforts have been made to characterize the expressed genes in the roots of non-model plants (root transcriptomes). This study was conducted to sequence, assemble, annotate, and characterize the root transcriptomes of three Caladium cultivars (Caladium × hortulanum) using RNA-Seq. The Caladium cultivars used in this study have different levels of resistance to Pythiummyriotylum, the most damaging necrotrophic pathogen to Caladium roots. Forty-six to 61 million clean reads were obtained for each Caladium root transcriptome. De novo assembly of the reads resulted in approximately 130,000 unigenes. Based on bioinformatic analysis, 71,825 (52.3%) Caladium unigenes were annotated for putative functions, 48,417 (67.4%) and 31,417 (72.7%) were assigned to Gene Ontology (GO) and Clusters of Orthologous Groups (COG), respectively, and 46,406 (64.6%) unigenes were assigned to 128 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. A total of 4518 distinct unigenes were observed only in Pythium-resistant "Candidum" roots, of which 98 seemed to be involved in disease resistance and defense responses. In addition, 28,837 simple sequence repeat sites and 44,628 single nucleotide polymorphism sites were identified among the three Caladium cultivars. These root transcriptome data will be valuable for further genetic improvement of Caladium and related aroids.
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a single gene controls leaf background color in Caladium araceae and is tightly linked to genes for leaf main vein color spotting and rugosity
Horticulture research, 2017Co-Authors: Qian Yang, Zhanao DengAbstract:Modern cultivated Caladiums (Caladium×hortulanum) are grown for their long-lasting and colorful leaves. Understanding the mode of inheritance for Caladium leaf characteristics is critical for plant breeders to select appropriate parents, predict progeny performance, estimate breeding population sizes needed, and increase breeding efficiencies. This study was conducted to determine the mode of inheritance of two leaf background colors (lemon and green) in Caladium and to understand their relationships with four other important leaf characteristics including leaf shape, main vein color, spotting, and rugosity. Seven Caladium cultivars and three breeding lines were used as parents in 19 crosses, and their progeny were phenotyped for segregation of leaf traits. Results showed that the two leaf background colors are controlled by a single nuclear locus, with two alleles, LEM and lem, which control the dominant lemon and the recessive green leaf background color, respectively. The lemon-colored cultivar ‘Miss Muffet’ and breeding lines UF-52 and UF-53 have a heterozygous genotype LEMlem. Chi-square tests showed that the leaf background color locus LEM is independent from the leaf shape locus F, but is tightly linked to three loci (S, V and RLF) controlling leaf spotting, main vein color, and rugosity in Caladium. A linkage map that consists of four loci controlling major Caladium leaf characteristics and extends ~15 cM was developed based on the observed recombination frequencies. This is the first report on the mode of inheritance of leaf background colors in Caladium and in the Araceae family. The information gained in this study will be very useful for Caladium breeding and study of the inheritance of leaf colors in other ornamental aroids, an important group of ornamental plants in the world. An analysis of the genes underlying leaf color in a popular ornamental enhances prospects for breeding novel color combinations. Cultivated Caladium species — known as ‘elephant ears’ — in the family Araceae are widely grown for their decorative leaves. Using a traditional crossbreeding approach, Zhanao Deng at the University of Florida, USA, and colleagues have explored the genetics of Caladium background leaf color. They found the two main variants, lemon and green, are inherited in a simple ‘Mendelian’ fashion, with lemon dominant to green. They then checked for associations between leaf color and other traits. While leaf shape was inherited separately, leaf spotting, vein color and rugosity (texture) all appeared to be closely linked to background leaf color. This information will be useful for breeding not only Caladiums, but also other understudied ornamental Araceae.
Brent K. Harbaugh - One of the best experts on this subject based on the ideXlab platform.
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uf 4412 and uf 4424 red lance leaved Caladium cultivars
Hortscience, 2013Co-Authors: Zhanao Deng, Brent K. Harbaugh, Natalia A. PeresAbstract:Cultivated Caladiums (Caladium 3hortulanum Birdsey, Araceae Juss.) are valued for their colorful and variable-shaped leaves (Harbaugh and Tjia, 1985; Wilfret, 1993). Cultivars generally are divided into three groups according to leaf shape and size: fancy-, lance-, and strap-leaved (Wilfret, 1986). Fancy-leaved Caladiums produce large round–ovate to triangular leaves with three main veins, two large basal lobes partially to fully joined, and a petiole attached to the back of the leaf blade. Strap-leaved Caladiums have linear leaves with one main vein and no obvious basal lobes. Lance-leaved Caladiums produce leaves intermediate between fancy and strap types: leaves sagittate to cordate–lanceolate in shape, basal lobes obvious to barely obvious, and petioles attached to the base of the leaves (Deng and Harbaugh, 2006a). The majority of Caladium cultivars in commercial production are fancy-leaved (Bell et al., 1998; Deng et al., 2011). However, there has been an increasing demand for lanceleaved cultivars. Florida growers, the primary supplier of Caladium tubers used in the world, reported greater than 50% more acres used for producing lance-leaved Caladiums in 2008 than in 1998 (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Plants of lance-leaved cultivars generally are more compact with smaller leaves and shorter petioles than fancy-leaved Caladiums. Tubers produced by lance-leaved Caladiums tend to be more branched (Deng and Harbaugh, 2008). Therefore, lance-leaved Caladiums are adaptable to different container sizes, do not require tuber de-eyeing for pot plant production, and are less expensive and easier to ship from production sites to markets. These characteristics result in significant benefits to growers producing and marketing potted Caladium plants (Deng and Harbaugh, 2008). Lance-leaved Caladiums may be more resilient to wind damage, drought, sunburn, and shading than fancy-leaved Caladiums and may do better than the latter in the landscape when such stresses occur (Deng and Harbaugh, 2008). However, many lance-leaved Caladiums often produce small tubers (Wilfret, 1983). Tubers are both the planting stock and the crop for Caladium growers. Thus, tuber yield is one of the most important factors determining a cultivar’s economic value for commercial production of Caladium tubers. Growers cannot produce cultivars profitably without adequate tuber yield and have to eliminate them from commercial production. Thus, developing new lance-leaved Caladium cultivars with adequate tuber yield potential has been a priority breeding objective for the University of Florida (UF) Caladium breeding program since its beginning in 1976. Currently, ‘Florida Sweetheart’ is the most popular lance-leaved commercial cultivar of any color, and ‘Florida Red Ruffles’ is the most popular red lance-leaved commercial cultivar among Caladium growers, greenhouse growers, and nurseries (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Both cultivars were introduced by the UF Caladium breeding program. Plants of ‘Florida Sweetheart’ are compact and produce wide lance leaves with a rosy color and relatively large tubers (Wilfret, 1991a). ‘Florida Red Ruffles’ has a compact, upright growth habit and excellent sunburn tolerance (Wilfret 1991b). UF 4412 (Fig. 1) and UF 4424 (Fig. 2) are attractive lance-leaved cultivars with novel, distinct combinations of plant and foliar characteristics. UF 4412 leaves are heartshaped like ‘Florida Sweetheart’ but have a large red center and numerous netted red veins. UF 4412 plants are taller and produce longer and wider leaves than ‘Florida Sweetheart’ plants. UF 4424 leaves are cordate– lanceolate-like ‘Florida Red Ruffles’ leaves but have a large, glossy, red center and numerous red, thick veins. UF 4412 and UF 4424 were comparable or superior in replicated field, greenhouse, and landscape trials
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UF 4412 and UF 4424—Red Lance-leaved Caladium Cultivars
HortScience, 2013Co-Authors: Zhanao Deng, Brent K. Harbaugh, Natalia A. PeresAbstract:Cultivated Caladiums (Caladium 3hortulanum Birdsey, Araceae Juss.) are valued for their colorful and variable-shaped leaves (Harbaugh and Tjia, 1985; Wilfret, 1993). Cultivars generally are divided into three groups according to leaf shape and size: fancy-, lance-, and strap-leaved (Wilfret, 1986). Fancy-leaved Caladiums produce large round–ovate to triangular leaves with three main veins, two large basal lobes partially to fully joined, and a petiole attached to the back of the leaf blade. Strap-leaved Caladiums have linear leaves with one main vein and no obvious basal lobes. Lance-leaved Caladiums produce leaves intermediate between fancy and strap types: leaves sagittate to cordate–lanceolate in shape, basal lobes obvious to barely obvious, and petioles attached to the base of the leaves (Deng and Harbaugh, 2006a). The majority of Caladium cultivars in commercial production are fancy-leaved (Bell et al., 1998; Deng et al., 2011). However, there has been an increasing demand for lanceleaved cultivars. Florida growers, the primary supplier of Caladium tubers used in the world, reported greater than 50% more acres used for producing lance-leaved Caladiums in 2008 than in 1998 (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Plants of lance-leaved cultivars generally are more compact with smaller leaves and shorter petioles than fancy-leaved Caladiums. Tubers produced by lance-leaved Caladiums tend to be more branched (Deng and Harbaugh, 2008). Therefore, lance-leaved Caladiums are adaptable to different container sizes, do not require tuber de-eyeing for pot plant production, and are less expensive and easier to ship from production sites to markets. These characteristics result in significant benefits to growers producing and marketing potted Caladium plants (Deng and Harbaugh, 2008). Lance-leaved Caladiums may be more resilient to wind damage, drought, sunburn, and shading than fancy-leaved Caladiums and may do better than the latter in the landscape when such stresses occur (Deng and Harbaugh, 2008). However, many lance-leaved Caladiums often produce small tubers (Wilfret, 1983). Tubers are both the planting stock and the crop for Caladium growers. Thus, tuber yield is one of the most important factors determining a cultivar’s economic value for commercial production of Caladium tubers. Growers cannot produce cultivars profitably without adequate tuber yield and have to eliminate them from commercial production. Thus, developing new lance-leaved Caladium cultivars with adequate tuber yield potential has been a priority breeding objective for the University of Florida (UF) Caladium breeding program since its beginning in 1976. Currently, ‘Florida Sweetheart’ is the most popular lance-leaved commercial cultivar of any color, and ‘Florida Red Ruffles’ is the most popular red lance-leaved commercial cultivar among Caladium growers, greenhouse growers, and nurseries (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Both cultivars were introduced by the UF Caladium breeding program. Plants of ‘Florida Sweetheart’ are compact and produce wide lance leaves with a rosy color and relatively large tubers (Wilfret, 1991a). ‘Florida Red Ruffles’ has a compact, upright growth habit and excellent sunburn tolerance (Wilfret 1991b). UF 4412 (Fig. 1) and UF 4424 (Fig. 2) are attractive lance-leaved cultivars with novel, distinct combinations of plant and foliar characteristics. UF 4412 leaves are heartshaped like ‘Florida Sweetheart’ but have a large red center and numerous netted red veins. UF 4412 plants are taller and produce longer and wider leaves than ‘Florida Sweetheart’ plants. UF 4424 leaves are cordate– lanceolate-like ‘Florida Red Ruffles’ leaves but have a large, glossy, red center and numerous red, thick veins. UF 4412 and UF 4424 were comparable or superior in replicated field, greenhouse, and landscape trials
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UF 44-4: A Dwarf Red Lance-leaved Caladium Cultivar
HortScience, 2011Co-Authors: Zhanao Deng, Brent K. HarbaughAbstract:Cultivated Caladiums (Caladium·hortulanum Birdsey) are valued for their bright colorful leaves (Evans et al., 1992). They can be broadly classified into three groups based on leaf shape: fancy, lance, and strap (Deng and Harbaugh, 2006; Wilfret, 1986). Fancy-leaved Caladiums have heart-shaped leaves with three main veins, petiole attachment peltate, and they have two large basal lobes. Strap-leaved Caladiums have narrow, linear leaves with one main vein and no obvious basal lobes. Lance leaves are intermediate between fancy and strap types with leaf blades that are broad sagittate to cordate– lanceolate. Basal lobes on different lanceleaved cultivars range from obvious to barely visible. In addition to leaf shape, lance-leaved Caladiums differ from fancy-leaved Caladiums in a number of plant, foliar, and tuber characteristics. Plants of lance-leaved Caladiums are generally shorter and have thicker and denser leaves than fancy-leaved Caladiums. Tubers are more branched, and main eyes are less dominant over secondary eyes compared with fancyleaved cultivars. De-eyeing (removal or destruction of the main eye or bud on tubers) is generally not necessary when forcing multibranched tubers of lance-leaved Caladiums in containers, even in small pots (4 inches in diameter). With a compact growth habit, lance-leaved Caladiums are very adaptable to different types and sizes of containers. Shorter and/or smaller pot plants are easier and less expensive to ship. Lance-leaved Caladiums also appear to be more resilient to sunburns, wind damage, drought, and shading than fancy-leaved Caladiums. These characteristics allow lance-leaved Caladiums to perform well in the landscape when such stresses occur. The majority (greater than 95%) of Caladium tubers used in the United States and abroad are produced in Florida. Florida growers supply as many as 50 to 70 million Caladium tubers to greenhouse growers, nurseries, and homeowners throughout the United States and Canada and to some 40 countries in Europe and Asia. The majority of Caladium cultivars in commercial production are the fancy-leaved type (Bell et al., 1998; Deng et al., 2005). However, during the past two or three decades, the demand for lance-leaved cultivars has increased steadily. For example, Florida growers planted greater than 50% more acres with lance-leaved cultivars in 2003 than in 1998 (Bell et al., 1998; Deng et al., 2005). Lance-leaved cultivars are expected to gain even greater popularity in the future. UF 44-4 is an attractive lance-leaved cultivar with a novel combination of leaf characteristics (bright red color, slightly undulate, and rounded leaf shape) (Figs. 1 and 2). In replicated field and greenhouse trials, it was comparable or superior to ‘Florida Red Ruffles’ and ‘Florida Sweetheart’ (the most popular red lance-leaved commercial cultivar and the most popular lance-leaved cultivar in all colors, respectively) in tuber yield potential, pot plant quality, and landscape performance. UF 44-4 is well suited for producing pot plants and hanging baskets, and de-eyeing is not required for forcing in smallor medium-sized containers (11.4 to 15.3 cm).
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Leaf Blotching in Caladium (Araceae) Is Under Simple Genetic Control and Tightly Linked to Vein Color
HortScience, 2009Co-Authors: Zhanao Deng, Brent K. HarbaughAbstract:Cultivated Caladiums (Caladium ·hortulanum Birdsey) are valued as important pot and landscape plants because of their bright, colorful leaves. Improving leaf characteristics or generating new combinations of these characteristics has been one of the most important breeding objectives in Caladium. A major leaf characteristic in Caladium is leaf blotching, the presence of numerous irregularly shaped color areas between major veins on leaf blades. This pattern of coloration in combination with bright colors has resulted in the popularity of a number of Caladium cultivars. In this study, controlled crosses were made among three blotched and six nonblotched Caladium cultivars. Their progeny were analyzed to understand the mode of inheritance of leaf blotching and its genetic relationship with the color of main leaf veins. Progeny of selfing nonblotched or crossing nonblotched cultivars were all nonblotched; selfing blotched cultivars (Carolyn Whorton, White Christmas, and Florida Blizzard) or crossing 'Florida Blizzard' and 'Carolyn Whorton' resulted in a 3:1 ratio (blotched:non- blotched); and progeny from crosses between blotched and nonblotched cultivars segregated in a 1:1 ratio (blotched:nonblotched). These results indicate that leaf blotching is controlled by a single nuclear locus with two alleles (B and b). x 2 analysis of the joint segregation between leaf blotching and vein color (V) in five crosses showed that the blotching allele Bis linked to the green vein alleleV g . 'Carolyn Whorton', 'White Christmas', and 'Florida Blizzard' are heterozygous for leaf blotching, and their genotype for leaf blotching and vein color (V r , V w , and V g for red, white, and green veins, respectively) are V r b//V g B, V g b//V g B, and V w b//V g B, respectively. This information will be valuable for planning crosses and breeding populations to develop new blotched Caladium cultivars. The information gainedin thisstudy may be helpful for understanding the inheritance of similar traits in other aroids.
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Caladium 75-14, a Spotted, Fancy-leaved Cultivar for Containers and Sunny Landscapes
HortScience, 2009Co-Authors: Zhanao Deng, Brent K. HarbaughAbstract:As a common pot and landscape plant, Caladium (Caladium ·hortulanum Birdsey, Araceae Juss.) is valued for its colorful leaves and low maintenance requirements (Evans et al., 1992). Commercial Caladium plants are grown from tubers. Central Florida growers produce greater than 95% of the tubers for the worldwide market (Bell et al., 1998; Deng et al., 2005). Tuber yield is one of the primary factors determining a Caladium cultivar’s production value and whether the cultivar will be acceptable to growers and viable in commercial production. Poor tuber yield has been one of the main reasons why many early cultivars were removed from commercial tuber production and many new breeding lines with novel colors or coloration patterns have not become commercialized. Developing Caladium cultivars with good tuber yield has been one of the main breeding objectives for the University of Florida’s Caladium breeding program at the Gulf Coast Research and Education Center since the program began in 1976. Caladium 75-14 (Figs. 1 and 2) is a new spotted, fancy-leaved cultivar with superior tuber yield. Plants of Caladium 75-14 are vigorous and can quickly fill a landscape space. Its leaves are resistant to sunburn, allowing this cultivar to perform well in full-sun landscapes. With its multiple branching habit and plant vigor, Caladium 75-14 produces high-quality plants in container forcing.
Zhe Cao - One of the best experts on this subject based on the ideXlab platform.
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morphological cytological and molecular marker analyses of tapestry Caladium variants reveal diverse genetic changes and enable association of leaf coloration pattern loci with molecular markers
Plant Cell Tissue and Organ Culture, 2020Co-Authors: Zhe Cao, Zhanao DengAbstract:Somaclonal variation and induced mutation are highly valuable sources of genetic variation for genetic improvement and research in horticultural crops; cellular and molecular characterization can greatly facilitate their uses in these areas. In the present study, 20 Caladium variants were identified among ‘Tapestry’ plants that were regenerated from leaf cultures treated with or without colchicine. These variants showed changes in leaf main vein color and coloration pattern and were separated into ten groups based on leaf morphological changes. Five variants contained 3.3–9.7% more nuclear DNA than the wildtype and gained one, two or three chromosomes, while four variants contained 3.0–4.8% less nuclear DNA and lost one chromosome. Five, out of 22, simple sequence repeat-based molecular markers detected DNA banding pattern changes in 13 of the 20 variants. Two molecular markers (CaM24 and CaM62) detected DNA banding pattern changes in the same four variants, suggesting that these two markers may be located in the same chromosomal segment. Strong association between leaf characteristics (leaf blotching and main vein color) and molecular banding pattern changes with molecular marker CaM42 were observed in six variants, indicating that CaM42 may be associated with gene loci controlling leaf blotching and leaf main vein color in Caladium. Detailed characterization of ‘Tapestry’ Caladium variants revealed changes in nuclear DNA content, chromosome number and molecular marker banding pattern and associated gene loci controlling leaf characters with molecular markers.
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De Novo Assembly, Annotation, and Characterization of Root Transcriptomes of Three Caladium Cultivars with a Focus on Necrotrophic Pathogen Resistance/Defense-Related Genes.
International journal of molecular sciences, 2017Co-Authors: Zhe Cao, Zhanao DengAbstract:Roots are vital to plant survival and crop yield, yet few efforts have been made to characterize the expressed genes in the roots of non-model plants (root transcriptomes). This study was conducted to sequence, assemble, annotate, and characterize the root transcriptomes of three Caladium cultivars (Caladium × hortulanum) using RNA-Seq. The Caladium cultivars used in this study have different levels of resistance to Pythiummyriotylum, the most damaging necrotrophic pathogen to Caladium roots. Forty-six to 61 million clean reads were obtained for each Caladium root transcriptome. De novo assembly of the reads resulted in approximately 130,000 unigenes. Based on bioinformatic analysis, 71,825 (52.3%) Caladium unigenes were annotated for putative functions, 48,417 (67.4%) and 31,417 (72.7%) were assigned to Gene Ontology (GO) and Clusters of Orthologous Groups (COG), respectively, and 46,406 (64.6%) unigenes were assigned to 128 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. A total of 4518 distinct unigenes were observed only in Pythium-resistant "Candidum" roots, of which 98 seemed to be involved in disease resistance and defense responses. In addition, 28,837 simple sequence repeat sites and 44,628 single nucleotide polymorphism sites were identified among the three Caladium cultivars. These root transcriptome data will be valuable for further genetic improvement of Caladium and related aroids.
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a single gene controls leaf background color in Caladium araceae and is tightly linked to genes for leaf main vein color spotting and rugosity
Horticulture research, 2017Co-Authors: Zhe Cao, Qian Yang, Shunzhao Sui, Zhanao DengAbstract:Modern cultivated Caladiums (Caladium×hortulanum) are grown for their long-lasting and colorful leaves. Understanding the mode of inheritance for Caladium leaf characteristics is critical for plant breeders to select appropriate parents, predict progeny performance, estimate breeding population sizes needed, and increase breeding efficiencies. This study was conducted to determine the mode of inheritance of two leaf background colors (lemon and green) in Caladium and to understand their relationships with four other important leaf characteristics including leaf shape, main vein color, spotting, and rugosity. Seven Caladium cultivars and three breeding lines were used as parents in 19 crosses, and their progeny were phenotyped for segregation of leaf traits. Results showed that the two leaf background colors are controlled by a single nuclear locus, with two alleles, LEM and lem, which control the dominant lemon and the recessive green leaf background color, respectively. The lemon-colored cultivar 'Miss Muffet' and breeding lines UF-52 and UF-53 have a heterozygous genotype LEMlem. Chi-square tests showed that the leaf background color locus LEM is independent from the leaf shape locus F, but is tightly linked to three loci (S, V and RLF) controlling leaf spotting, main vein color, and rugosity in Caladium. A linkage map that consists of four loci controlling major Caladium leaf characteristics and extends ~15 cM was developed based on the observed recombination frequencies. This is the first report on the mode of inheritance of leaf background colors in Caladium and in the Araceae family. The information gained in this study will be very useful for Caladium breeding and study of the inheritance of leaf colors in other ornamental aroids, an important group of ornamental plants in the world.
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Inheritance of Rugose Leaf in Caladium and Genetic Relationships with Leaf Shape, Main Vein Color, and Leaf Spotting
Journal of the American Society for Horticultural Science, 2016Co-Authors: Zhe Cao, Qian Yang, Shunzhao Sui, Zhanao DengAbstract:A number of Caladium cultivars (Caladium ×hortulanum), including Miss Muffet and Gingerland, produce rugose leaves. The rugosity on these leaves is an intriguing characteristic, often resulting in an increased ornamental value. This study was conducted to understand the mode of inheritance of this trait and to determine its genetic relationship with other foliar characteristics including leaf shape, main vein color, and leaf spotting in Caladiums. Sixteen Caladium cultivars/breeding lines were crossed and 20 populations were produced; progeny of these populations were phenotyped for rugose leaf as well as leaf shape, main vein color, and leaf spotting. Results showed that a single locus with two alleles controlled the presence or absence of rugose leaves in these populations. The locus was designated as RLF, with the dominant RLF allele for rugose leaves and the recessive allele rlf for nonrugose (flat) leaves. Rugose cultivars Miss Muffet and Gingerland and breeding line UF-317 possessed the heterozygous genotype RLFrlf. Rugose leaf was inherited independently from leaf shape, but linked with the green main vein allele (Vg) at the V locus and the leaf spotting allele (S) at the S locus. Three-point analysis of the segregation of the three linked traits in reciprocal crosses between ‘Miss Muffet’ and nonrugose ‘Candidum’ indicated a genetic linkage map with the gene order of S locus locating between the V and the RLF loci. The information obtained from this study will be useful for developing breeding strategies for producing new Caladium cultivars with or without rugose leaves, and can facilitate the understanding of the mode of inheritance for rugose leaves in other aroids and other plants.
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Induction, regeneration and characterization of tetraploids and variants in ‘Tapestry’ Caladium
Plant Cell Tissue and Organ Culture (PCTOC), 2014Co-Authors: Xiao-dong Cai, Zhe Cao, Zhanao DengAbstract:Caladium (Caladium × hortulanum Birdsey) is an important ornamental aroid that is valued for its long-lasting colorful foliage. Genetic improvement and cultivar development in Caladium have been primarily achieved through sexual hybridization, and there is a strong need to explore in vitro-based approaches to generate novel phenotypic variations in Caladium. This study was conducted to develop an efficient in vitro chromosome doubling technique for Caladium, to assess the effects of chromosome doubling on Caladium leaf morphology, and to identify promising Caladium tetraploids for breeding. Leaf segments of ‘Tapestry’ Caladium were pre-cultured in vitro, treated with colchicine, and then cultured to regenerate tetraploid plants. Out of 501 established plants, 56 showed considerable variation from the wildtype in leaf shape, color, coloration pattern, and/or thickness. Ploidy analysis showed that 48 appeared to be tetraploids, and the remaining eight appeared to be diploids. In two treatments with 0.1 or 0.2 % (w/v) colchicine for 4 days, 13.74 and 24.14 % of the regenerated plants were tetraploids. Caladium tetraploids exhibited round and thick leaves with thick petioles. These morphological changes were a reliable morphological indicator for visual screening for tetraploids in Caladium. Based on observed morphological changes, the eight diploid variants were categorized into five variant types (VT1–VT5), and the 48 tetraploid variants were categorized into another five variant types (VT6–VT10). Most Caladium plants in VT1, VT2, VT3, VT6, and VT7 showed much improved ornamental values and held potential as promising new selections for container and landscape performance trials and tuber yield tests. Nuclear DNA content and chromosome number analysis were conducted on 17 representative variants; results revealed the two diploid variants had gained one or two additional chromosomes, one tetraploid variant gained four additional chromosomes, and two tetraploid variants lost two or four chromosomes. These results demonstrate for the first time in Caladium that in vitro induction of tetraploids is a very powerful tool for generating novel phenotypes for genetic improvement and breeding and that chromosome gain or loss is a common type of cytological variation in Caladium.
Natalia A. Peres - One of the best experts on this subject based on the ideXlab platform.
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uf 4412 and uf 4424 red lance leaved Caladium cultivars
Hortscience, 2013Co-Authors: Zhanao Deng, Brent K. Harbaugh, Natalia A. PeresAbstract:Cultivated Caladiums (Caladium 3hortulanum Birdsey, Araceae Juss.) are valued for their colorful and variable-shaped leaves (Harbaugh and Tjia, 1985; Wilfret, 1993). Cultivars generally are divided into three groups according to leaf shape and size: fancy-, lance-, and strap-leaved (Wilfret, 1986). Fancy-leaved Caladiums produce large round–ovate to triangular leaves with three main veins, two large basal lobes partially to fully joined, and a petiole attached to the back of the leaf blade. Strap-leaved Caladiums have linear leaves with one main vein and no obvious basal lobes. Lance-leaved Caladiums produce leaves intermediate between fancy and strap types: leaves sagittate to cordate–lanceolate in shape, basal lobes obvious to barely obvious, and petioles attached to the base of the leaves (Deng and Harbaugh, 2006a). The majority of Caladium cultivars in commercial production are fancy-leaved (Bell et al., 1998; Deng et al., 2011). However, there has been an increasing demand for lanceleaved cultivars. Florida growers, the primary supplier of Caladium tubers used in the world, reported greater than 50% more acres used for producing lance-leaved Caladiums in 2008 than in 1998 (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Plants of lance-leaved cultivars generally are more compact with smaller leaves and shorter petioles than fancy-leaved Caladiums. Tubers produced by lance-leaved Caladiums tend to be more branched (Deng and Harbaugh, 2008). Therefore, lance-leaved Caladiums are adaptable to different container sizes, do not require tuber de-eyeing for pot plant production, and are less expensive and easier to ship from production sites to markets. These characteristics result in significant benefits to growers producing and marketing potted Caladium plants (Deng and Harbaugh, 2008). Lance-leaved Caladiums may be more resilient to wind damage, drought, sunburn, and shading than fancy-leaved Caladiums and may do better than the latter in the landscape when such stresses occur (Deng and Harbaugh, 2008). However, many lance-leaved Caladiums often produce small tubers (Wilfret, 1983). Tubers are both the planting stock and the crop for Caladium growers. Thus, tuber yield is one of the most important factors determining a cultivar’s economic value for commercial production of Caladium tubers. Growers cannot produce cultivars profitably without adequate tuber yield and have to eliminate them from commercial production. Thus, developing new lance-leaved Caladium cultivars with adequate tuber yield potential has been a priority breeding objective for the University of Florida (UF) Caladium breeding program since its beginning in 1976. Currently, ‘Florida Sweetheart’ is the most popular lance-leaved commercial cultivar of any color, and ‘Florida Red Ruffles’ is the most popular red lance-leaved commercial cultivar among Caladium growers, greenhouse growers, and nurseries (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Both cultivars were introduced by the UF Caladium breeding program. Plants of ‘Florida Sweetheart’ are compact and produce wide lance leaves with a rosy color and relatively large tubers (Wilfret, 1991a). ‘Florida Red Ruffles’ has a compact, upright growth habit and excellent sunburn tolerance (Wilfret 1991b). UF 4412 (Fig. 1) and UF 4424 (Fig. 2) are attractive lance-leaved cultivars with novel, distinct combinations of plant and foliar characteristics. UF 4412 leaves are heartshaped like ‘Florida Sweetheart’ but have a large red center and numerous netted red veins. UF 4412 plants are taller and produce longer and wider leaves than ‘Florida Sweetheart’ plants. UF 4424 leaves are cordate– lanceolate-like ‘Florida Red Ruffles’ leaves but have a large, glossy, red center and numerous red, thick veins. UF 4412 and UF 4424 were comparable or superior in replicated field, greenhouse, and landscape trials
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UF 4412 and UF 4424—Red Lance-leaved Caladium Cultivars
HortScience, 2013Co-Authors: Zhanao Deng, Brent K. Harbaugh, Natalia A. PeresAbstract:Cultivated Caladiums (Caladium 3hortulanum Birdsey, Araceae Juss.) are valued for their colorful and variable-shaped leaves (Harbaugh and Tjia, 1985; Wilfret, 1993). Cultivars generally are divided into three groups according to leaf shape and size: fancy-, lance-, and strap-leaved (Wilfret, 1986). Fancy-leaved Caladiums produce large round–ovate to triangular leaves with three main veins, two large basal lobes partially to fully joined, and a petiole attached to the back of the leaf blade. Strap-leaved Caladiums have linear leaves with one main vein and no obvious basal lobes. Lance-leaved Caladiums produce leaves intermediate between fancy and strap types: leaves sagittate to cordate–lanceolate in shape, basal lobes obvious to barely obvious, and petioles attached to the base of the leaves (Deng and Harbaugh, 2006a). The majority of Caladium cultivars in commercial production are fancy-leaved (Bell et al., 1998; Deng et al., 2011). However, there has been an increasing demand for lanceleaved cultivars. Florida growers, the primary supplier of Caladium tubers used in the world, reported greater than 50% more acres used for producing lance-leaved Caladiums in 2008 than in 1998 (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Plants of lance-leaved cultivars generally are more compact with smaller leaves and shorter petioles than fancy-leaved Caladiums. Tubers produced by lance-leaved Caladiums tend to be more branched (Deng and Harbaugh, 2008). Therefore, lance-leaved Caladiums are adaptable to different container sizes, do not require tuber de-eyeing for pot plant production, and are less expensive and easier to ship from production sites to markets. These characteristics result in significant benefits to growers producing and marketing potted Caladium plants (Deng and Harbaugh, 2008). Lance-leaved Caladiums may be more resilient to wind damage, drought, sunburn, and shading than fancy-leaved Caladiums and may do better than the latter in the landscape when such stresses occur (Deng and Harbaugh, 2008). However, many lance-leaved Caladiums often produce small tubers (Wilfret, 1983). Tubers are both the planting stock and the crop for Caladium growers. Thus, tuber yield is one of the most important factors determining a cultivar’s economic value for commercial production of Caladium tubers. Growers cannot produce cultivars profitably without adequate tuber yield and have to eliminate them from commercial production. Thus, developing new lance-leaved Caladium cultivars with adequate tuber yield potential has been a priority breeding objective for the University of Florida (UF) Caladium breeding program since its beginning in 1976. Currently, ‘Florida Sweetheart’ is the most popular lance-leaved commercial cultivar of any color, and ‘Florida Red Ruffles’ is the most popular red lance-leaved commercial cultivar among Caladium growers, greenhouse growers, and nurseries (Bell et al., 1998; Deng and Alleyne, 2009; Deng et al., 2011). Both cultivars were introduced by the UF Caladium breeding program. Plants of ‘Florida Sweetheart’ are compact and produce wide lance leaves with a rosy color and relatively large tubers (Wilfret, 1991a). ‘Florida Red Ruffles’ has a compact, upright growth habit and excellent sunburn tolerance (Wilfret 1991b). UF 4412 (Fig. 1) and UF 4424 (Fig. 2) are attractive lance-leaved cultivars with novel, distinct combinations of plant and foliar characteristics. UF 4412 leaves are heartshaped like ‘Florida Sweetheart’ but have a large red center and numerous netted red veins. UF 4412 plants are taller and produce longer and wider leaves than ‘Florida Sweetheart’ plants. UF 4424 leaves are cordate– lanceolate-like ‘Florida Red Ruffles’ leaves but have a large, glossy, red center and numerous red, thick veins. UF 4412 and UF 4424 were comparable or superior in replicated field, greenhouse, and landscape trials
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Characterization of Strains of Xanthomonas axonopodis pv. dieffenbachiae from Bacterial Blight of Caladium and Identification of Sources of Resistance for Breeding Improved Cultivars
HortScience, 2010Co-Authors: T. E. Seijo, Natalia A. Peres, Zhanao DengAbstract:Bacterial blight., caused by Xanthomonas axonopodis pv. dieffenbachiae (Xad), is the most common foliar disease of Caladium, an ornamental aroid grown for its colorful foliage. The disease can reduce the marketability of Caladiums produced as potted plants and lower the yield of Caladiums grown for tuber production. Three bacterial strains were isolated from symptomatic Caladiums and identified as Xad using fatty, acid analysis, carbon source use, and the sequence of the 16S-23S spacer, and tested for virulence against three susceptible cultivars. Two strains were virulent to all of the cultivars; however, one strain was differentially, pathogenic, virulent against two cultivars, but not to the usually highly, susceptible 'Candidum'. In greenhouse inoculation tests of 17 cultivars and one breeding line, four cultivars were ranked as highly susceptible, nine as moderately susceptible, and five as resistant. Ten of these cultivars were also evaluated with natural infection in the field with good agreement between the results of the greenhouse and field evaluations. Cultivars White Queen, Florida Red Ruffles, Florida Sweetheart, Candidum Jr., and Mrs. Arno Nehrling have been identified as resistant to bacterial blight in greenhouse or field evaluations and can potentially, be used in future breeding efforts to produce improved cultivars.
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Toward Breeding for Resistance to Fusarium Tuber Rot in Caladium: Inoculation Technique and Sources of Resistance
HortScience, 2007Co-Authors: Fahrettin Goktepe, Zhanao Deng, Brent K. Harbaugh, Natalia A. Peres, T. E. Seijo, Robert J. McgovernAbstract:Fusarium tuber rot, incited by Fusarium solani, is the major cause of losses of tuber quality and quantity in Caladium (Caladium ·hortulanum) during storage and production. To develop a reliable inoculation method for evaluating cultivar suscepti- bility to Fusarium tuber rot and identifying sources of resistance, the effect of temperature on the mycelial growth of F. solani in vitro and on tuber rot in vivo was examined.TheoptimaltemperaturewasthenusedtostudytheaggressivenessofF.solani isolates. The effect of temperature (13, 18, 23, 28, and 33 8C) on radial mycelial growth of nine F. solani isolates in vitro was determined, and all responded similarly to temperature variables, with optimal growth predicted to be at 30.5 8C. The relationship of these temperatures to disease development was then determined for the most aggressive F. solani isolate 05-20 and it was found that disease development in inoculated tubers was greatest at low temperatures (13 and 18 8C). Cold damage to tubers was observed at 13 8C; therefore, 18 8C was chosen for all future disease screening. The aggressiveness of nine isolates was tested on two Caladium cultivars. Significant differ- ences among isolates were observed for the diameter of rotted tissue in both cultivars, indicating that choice of isolate was important for screening. Isolates 05-20 and 05-257 were highly aggressive on both cultivars. Tubers of 17 commercial Caladium cultivars were inoculated withthree isolates (04-03, 05-20, and 05-527) and incubated at 18 8C. The interaction between isolates and cultivars was highly significant (P < 0.0001), indicating that cultivars were not equally susceptible to different pathogenic isolates of F. solani. Lesion diameters differed significantly (P < 0.0001) among cultivars/isolates and ranged from 9.5 mm ('Rosebud' and 'White Christmas' for isolate 04-03) to 23.9 mm ('Carolyn Whorton' for isolate 05-20). The cultivars were ranked for susceptibility to tuber rot within each isolate and the normalized total rank for the three isolates was used to place cultivars into four categories: resistant ('Candidum', 'Rosebud', 'White Christmas', 'Florida Sweetheart', and 'Aaron'), moderately resistant ('White Wing' and 'Red Flash'), susceptible ('Candidum Jr.', 'White Queen', 'Red Frill', 'Florida Cardinal', 'Miss Muffet', and 'Postman Joyner'), and highly susceptible ('Fannie Munson', 'Gingerland', 'Frieda Hemple', and 'Carolyn Whorton'). The availability of these sources of host plant resistance, aggressive isolates, and resistance assessment techniques will facilitate the development of new Fusarium-resistant Caladium cultivars.
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Techniques to Evaluate Caladium Cultivars for Host Resistance to Fusarium Tuber Rot
HortScience, 2006Co-Authors: Fahrettin Goktepe, Zhanao Deng, Brent K. Harbaugh, T. E. Seijo, Natalia A. PeresAbstract:Caladiums, widely used in containers and landscapes as ornamental plants for their bright colorful leaves, are generally forced or grown from tubers. Commercial production of these tubers in central Florida is through dividing “seed” tubers and growing them in fields. Tuber quality is therefore of critical importance to success in container forcing, landscape use, and tuber production. Fusarium tuber rot (Fusarium solani) has been recognized as the most-destructive disease that affects Caladium tuber quality. There is anecdotal evidence from growers indicating the existence of resistance in commercial Caladium cultivars. To identify and confirm the source of fusarium tuber rot resistance in Caladium, F. solani isolates have been collected from rotting tubers grown under different soil conditions and from different locations. The pathogenecity of these isolates has been tested through artificial inoculation of fresh harvested and/or stored tubers, and a number of highly virulent isolates have been identified. These isolates have been used to refine inoculation and disease evaluation techniques. Two techniques, spraying a conidial suspension onto fresh cut surfaces and inserting Fusarium-infested carnation leaf segments into artificial wounds, have proven to yield consistent resistance/susceptibility ratings among cultivars of known difference in resistance to fusarium tuber rot. Appropriate incubation temperatures and humidity seem to be very critical for disease development and evaluation. The two techniques have been used to evaluate 35 cultivars. Several cultivars, including `Candidum', showed a high level of resistance to fusarium tuber rot, and may be good breeding parent for developing new resistant cultivars.
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induction of tetraploids in red flash Caladium using colchicine and oryzalin morphological cytological photosynthetic and chilling tolerance analysis
Scientia Horticulturae, 2020Co-Authors: Yuan-shan Zhang, Jin-jin Chen, Jia-xin Duan, Yun-mei Cao, Xiao-dong CaiAbstract:Abstract In vitro pre-cultured leaf segments of ‘Red Flash’ Caladium (Caladium × hortulanum Birdsey) were treated with 0.1%, 0.2% and 0.3% (w/v) colchicine, or 0.001%, 0.002% and 0.003% (w/v) oryzalin for 2, 4 and 6 days, respectively, with the aim to develop an efficient polyploid induction protocol for Caladium, and to identify promising Caladium variants for cultivar development and chilling tolerance breeding. A total of 206 out of 723 plants were found to exhibit stable and remarkable morphological changes, and were grouped into 10 variant types based on differences in leaf shape, color, and/or coloration. As many as 93 plants were identified preliminary as tetraploids by flow cytometry, and the most efficient way for chromosome doubling seemed to be exposed to 0.002% oryzalin for 6 days. Chromosome counting were performed to further determine the ploidy level of the variants as extensive variation of mean fluorescence intensity (MFI) were recorded among them, and results showed that chromosome gains or losses occurred frequently in the established variants. As compared to the wild type, tetraploidization resulted in plants with rounder and thicker leaves, larger petiole diameter, higher plant height, lower leaf number per plant, and lower stomatal density, and significantly increased the net photosynthesis rate, transpiration rate, and stomatal conductance. Furthermore, enhanced chilling tolerance were observed in the tetraploids (T1), as evidenced by their higher superoxide dismutase (SOD) activity, peroxidase (POD) activity and proline (Pro) content, and a lower relative electrical conductivity (REC) and malondialdehyde (MDA) content in the leaves compared with those of the diploid counterparts and the diploid aneuploids (SVT1) during chilling stress. The variants associated with valuable phenotypic traits including the tetraploids, diploid variants, diploid aneuploids, and tetraploid aneuploids hold considerable potential for cultivar development, genetic study and chromosome engineering in Caladium.
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Morphological, cytological, and pigment analysis of leaf color variants regenerated from long-term subcultured Caladium callus
In Vitro Cellular & Developmental Biology - Plant, 2020Co-Authors: Jin-jin Chen, Yuan-shan Zhang, Jia-xin Duan, Yun-mei Cao, Xiao-dong CaiAbstract:Cultivated Caladiums (Caladium × hortulanum Birdsey) are popular ornamental plants. Although somaclonal variation occurs frequently in Caladium during tissue culture, little research has been conducted on obtaining and detecting variants from long-term callus cultures. Herein, plants were regenerated from ‘Red Flash’ Caladium calluses subcultured for approximately 40 mo, and 116 out of 520 established plants were grouped into 14 somaclonal variation types based on their morphological differences. Nuclear DNA content of six types (SVT1, SVT2, SVT4, SVT5, SVT8, and SVT10) varied from − 1.08% to 0.33% compared with the wild type, and these variants shared a similar chromosome number to the wild Caladium (2n = 2x = 30). Three types (SVT3, SVT7, and SVT9) containing 2.82 to 5.42% less nuclear DNA content was the result of losing one or two chromosomes, and one type (SVT6) with significantly lower cellular DNA content was due to losing four chromosomes. Four types (SVT11–SVT14) contained 85.16 to 101.52% more DNA content and the SVT12 and the SVT13 had a double number of chromosomes (2n = 4x = 60), while the SVT11 and SVT14 had four more chromosomes and six less chromosomes as compared with a typical tetraploid, respectively. Correlation analysis suggested that leaf thickness, leaf index, and stomatal characteristics could be used as indicators of plant ploidy in Caladium. A wide variation of pigment content was found among the variation types, and the content of chlorophyll, flavonoid, and anthocyanin had a significant positive correlation with the color parameters a* and b*. Leaf color variants created by prolonged in vitro callus cultures might hold great promise for Caladium breeding.
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Induction of tetraploids in ‘Red Flash’ Caladium using colchicine and oryzalin: Morphological, cytological, photosynthetic and chilling tolerance analysis
Scientia Horticulturae, 2020Co-Authors: Yuan-shan Zhang, Jin-jin Chen, Jia-xin Duan, Yun-mei Cao, Xiao-dong CaiAbstract:Abstract In vitro pre-cultured leaf segments of ‘Red Flash’ Caladium (Caladium × hortulanum Birdsey) were treated with 0.1%, 0.2% and 0.3% (w/v) colchicine, or 0.001%, 0.002% and 0.003% (w/v) oryzalin for 2, 4 and 6 days, respectively, with the aim to develop an efficient polyploid induction protocol for Caladium, and to identify promising Caladium variants for cultivar development and chilling tolerance breeding. A total of 206 out of 723 plants were found to exhibit stable and remarkable morphological changes, and were grouped into 10 variant types based on differences in leaf shape, color, and/or coloration. As many as 93 plants were identified preliminary as tetraploids by flow cytometry, and the most efficient way for chromosome doubling seemed to be exposed to 0.002% oryzalin for 6 days. Chromosome counting were performed to further determine the ploidy level of the variants as extensive variation of mean fluorescence intensity (MFI) were recorded among them, and results showed that chromosome gains or losses occurred frequently in the established variants. As compared to the wild type, tetraploidization resulted in plants with rounder and thicker leaves, larger petiole diameter, higher plant height, lower leaf number per plant, and lower stomatal density, and significantly increased the net photosynthesis rate, transpiration rate, and stomatal conductance. Furthermore, enhanced chilling tolerance were observed in the tetraploids (T1), as evidenced by their higher superoxide dismutase (SOD) activity, peroxidase (POD) activity and proline (Pro) content, and a lower relative electrical conductivity (REC) and malondialdehyde (MDA) content in the leaves compared with those of the diploid counterparts and the diploid aneuploids (SVT1) during chilling stress. The variants associated with valuable phenotypic traits including the tetraploids, diploid variants, diploid aneuploids, and tetraploid aneuploids hold considerable potential for cultivar development, genetic study and chromosome engineering in Caladium.
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Induction, regeneration and characterization of tetraploids and variants in ‘Tapestry’ Caladium
Plant Cell Tissue and Organ Culture (PCTOC), 2014Co-Authors: Xiao-dong Cai, Zhe Cao, Zhanao DengAbstract:Caladium (Caladium × hortulanum Birdsey) is an important ornamental aroid that is valued for its long-lasting colorful foliage. Genetic improvement and cultivar development in Caladium have been primarily achieved through sexual hybridization, and there is a strong need to explore in vitro-based approaches to generate novel phenotypic variations in Caladium. This study was conducted to develop an efficient in vitro chromosome doubling technique for Caladium, to assess the effects of chromosome doubling on Caladium leaf morphology, and to identify promising Caladium tetraploids for breeding. Leaf segments of ‘Tapestry’ Caladium were pre-cultured in vitro, treated with colchicine, and then cultured to regenerate tetraploid plants. Out of 501 established plants, 56 showed considerable variation from the wildtype in leaf shape, color, coloration pattern, and/or thickness. Ploidy analysis showed that 48 appeared to be tetraploids, and the remaining eight appeared to be diploids. In two treatments with 0.1 or 0.2 % (w/v) colchicine for 4 days, 13.74 and 24.14 % of the regenerated plants were tetraploids. Caladium tetraploids exhibited round and thick leaves with thick petioles. These morphological changes were a reliable morphological indicator for visual screening for tetraploids in Caladium. Based on observed morphological changes, the eight diploid variants were categorized into five variant types (VT1–VT5), and the 48 tetraploid variants were categorized into another five variant types (VT6–VT10). Most Caladium plants in VT1, VT2, VT3, VT6, and VT7 showed much improved ornamental values and held potential as promising new selections for container and landscape performance trials and tuber yield tests. Nuclear DNA content and chromosome number analysis were conducted on 17 representative variants; results revealed the two diploid variants had gained one or two additional chromosomes, one tetraploid variant gained four additional chromosomes, and two tetraploid variants lost two or four chromosomes. These results demonstrate for the first time in Caladium that in vitro induction of tetraploids is a very powerful tool for generating novel phenotypes for genetic improvement and breeding and that chromosome gain or loss is a common type of cytological variation in Caladium.