For many decades, Dieffenbachia species and cultivars, members of the family Araceae, have been important to the ornamental tropical foliage plant industry. Dieffenbachia s’ ability to adapt to interior environments, its ease of production, and
Richard J. Henny, J. Chen and D.J. Norman
Richard J. Henny, James R. Holm, Jianjun Chen and Michelle Scheiber
Cultivars of the aroid genus Dieffenbachia are valued as ornamental plants for their attractive foliage, ease of production, and their durability as living specimens for interior decoration. Since 1980, with the control of flowering and
R. J. Henny, J. Chen and D.J. Norman
Species and cultivars of Dieffenbachia Schott. (Araceae Juss.) have been important ornamental foliage plants for many decades. Their attractive foliar variegation, adaptability to interior environments, and ease of production are major reasons for their importance as ornamental foliage plants. Approximately 20 cultivars are commercially produced in Florida. Previously, most new cultivars were clones introduced from the wild or chance mutations of existing cultivars. Currently, cultivars are introduced into production from plant breeding programs (Henny 1995a, b; Henny and Chen, 2003; Henny et al., 1987). The hybrid Dieffenbachia `Sterling' was developed by the tropical foliage plant breeding program at the Mid-Florida Research and Education Center.
Qiansheng Li, Jianjun Chen, Robert H. Stamps and Lawrence R. Parsons
in breeding programs for developing new cultivars with chilling tolerance ( Henny and Chen, 2004 ). Dieffenbachia , commonly known as dumb cane, is a member of the family Araceae and ranks among the top five most popular foliage plant genera
Silvia Jiménez, Mónica Pérez, Blanca María Plaza, Roberto Salinas and María Teresa Lao
prediction of the P nutritional needs of Dieffenbachia amoena to increase P use efficiency in a recycled system, although this model can also be applied in principle to other plant species. To achieve this, P uptake has been correlated to climate parameters
Silvia Jiménez Becker, Maria Teresa Lao and Mari Luz Segura
). Dieffenbachia amoena ‘Tropic Snow’ responds better to mixed N nutrition ( Jiménez and Lao, 2005 ). Therefore, to prevent nutrient disturbances and to optimize growth in closed hydroponics systems, specific knowledge is required for each particular plant species
Silvia Jiménez Becker, Blanca María Plaza and María Teresa Lao
potassium uptake; and 3) the development of empirical models that permit the prediction of the K nutritional needs of Dieffenbachia amoena . To achieve this, K uptake has been correlated to temperature (T), vapor pressure deficit (VPD), global radiation (Rg
Margaret J. McMahon, A.J. Pertuit Jr. and James E. Arnold
Leaves of chilled `Moss-Agate' Episcia (Mart.) plants exhibited direct chilling injury (i.e., watersoaked browning of leaf blade interveinal areas within 24 h of exposure to low temperature) immediately following exposure in darkness to 10C for 0.5 or 1.0 h. Chlorophyll fluorescence peak: initial ratios and terminal: peak ratios of chilled Episcia were -reduced 20% and 25%, respectively, 3 h after chilling, a result suggesting possible photosystem II damage. Total leaf chlorophyll content was reduced by 17% within 3 h of chilling and CO2uptake also was reduced at this time. Leaves of chilled `Rudolph Roehrs' Dieffenbachia maculata (Lodd.) (D. Roehrsii Hort.) plants expressed no visible injury within 24 h of 1.2C chilling in darkness for 36,48, or 60 h, but CO2uptake was reduced by 70% compared to the control 3 h after chilling. Visible injury began to appear 27 h after chilling, and the older leaf blades of all chilled plants exhibited a watersoaked appearance 75 h after chilling. Chlorophyll fluorescence peak: initial ratios of chilled Dieffenbachia did not vary, and terminal: peak ratios were not reduced until 147 h after chilling, when the injured tissue was extremely flaccid and translucent. Chilling reduced the chlorophyll content of Dieffenbachia by 10% in some plants 27 h after chilling and by 35%. in all plants 75 h after chilling. Transpiration rate was reduced and stomata] diffusive resistance increased 27 h after chilling.
D.J. Norman, R.J. Henny and J.M.F. Yuen
Twenty commonly grown Dieffenbachia cultivars were tested for their resistance to diseases affecting production caused by the following bacterial and fungal pathogens: Xanthomonas campestris pv. dieffenbachiae (McCulloch and Pirone) Dye, Erwinia chrysanthemi Burk, Fusarium solani Sacc, and Myrothecium roridum Tode ex Fr. Two isolates of each pathogen were used to compare heterogenic pathogen populations to the relatively homogenetic asexually produced cultivars. Cultivars having horizontal resistance toward tested pathogens could then easily be identified. The cultivars Camille, Compacta, and Parachute showed the broadest horizontal resistance, with resistance toward three of the four pathogen groups tested. Disease resistance identified in this research permits the selection of plants to be used in breeding, and also creates a baseline to compare resistance of newly developed cultivars.
Jianjun Chen, Richard J. Henny, David J. Norman, Pachanoor S. Devanand and Chih-Cheng T. Chao
Dieffenbachia Schott is an important ornamental foliage plant genus. A total of 30 species has been recognized, but most cultivars come from or are related to a single species, D. maculata (Lodd.) G. Don. At least 11 of the cultivars are sports or somaclonal variants. As a result, the potential lack of genetic diversity in cultivated Dieffenbachia has become a concern. However, no research has been conducted to determine the genetic relatedness of the cultivars. This study analyzed the genetic similarity of 42 Dieffenbachia cultivars using amplified fragment length polymorphism (AFLP) markers. Six primer sets, selected from an initial screening of 48, generated a total of 453 scorable AFLP fragments of which 323 (71%) are polymorphic. All cultivars were clearly differentiated by their AFLP fingerprints. A dendrogram was constructed using the unweighted pair-group method of arithmetic averages, and principal coordinated analysis was carried out to show multiple dimensions of the distribution of the cultivars. The 42 cultivars were divided into three clusters; clusters I and II comprise 18 and 23 cultivars, respectively. Jaccard's similarity coefficients for cultivars in the clusters I and II varied from 0.44 to 0.95 and 0.41 to 0.87, respectively. These results indicate that broadening the genetic variability in the Dieffenbachia gene pool is needed, but the genetic similarity of many cultivars is not as close as previously thought. Additionally, Jaccard's similarity coefficients between most sports or somaclonal variants and their parents were 0.73 or lower, suggesting that accumulation of somatic mutations through tissue culture may play a role in the increased variation between some sports or variants and their parents.