Kozai, 2004 ). Plants in the genus Zantedeschia K. Koch, referred to as a group as calla lilies, are important ornamental plants in demand internationally throughout the year ( Halligan et al., 2004 ; Leal-Rojas et al., 2007 ). Both white and colored
Maren E. Veatch-Blohm and Lindsay Morningstar
Ramona A. Reiser and Robert W. Langhans
The release of latent buds (adaptive reiteration) and aerial shoot architecture of the rhizomatous calla lily plant has been researched for pot production. Rhizome mapping has explicitly shown vegetative and floral bud positioning in relation to tissue growth and expansion. Floral initiation normally occurred only on the mother portion of rhizomes. Gibberellic acid (GA3) application enhanced this phenomenon and caused initiation on daughter ramets. Bud excision performed at planting through Day 16 microscopically revealed lack of floral initiation in dissected meristems prior to planting, transition by Day 4, elongation beginning at Day 8 and `small to medium sized spadixes present by Day 12 and 16. Floral development was similar in treated and untreated primary buds, but delayed in secondary and tertiary buds with elongation occurring by Day 16. Pretreatment of GA3 prior to planting revealed spadix presence at Day 0. Floral development correlated with ramet size showed most flowers on largest ramets but formation on all sizes with GA3 treatment. GA3 also caused increased vegetative bud formation on rhizomes.
James S. Gerik, Ian D. Greene, Peter Beckman, and Clyde L. Elmore
Two field trials were conducted from 2002 until 2004 to evaluate several chemicals as alternatives to methyl bromide for the production of calla lily (Zantedeschia sp.) rhizomes. Various rates and chemical combinations were tested. The chemicals were applied through a drip irrigation system. The chemicals included iodomethane, chloropicrin, 1,3-dichloropropene, metham, sodium furfural, and sodium azide. None of the treatments reduced the viability of seed of mallow (Malva parviflora) previously buried in the plots. Propagules of nutsedge (Cyperus esculentus) and seed of mustard (Brassica nigra) were controlled by iodomethane + chloropicrin, 1,3-dichloropropene + chloropicrin, chloropicrin alone, 1,3-dichloropropene alone, and furfural + metham sodium. Propagules of calla were controlled by all of the treatments except sodium azide and furfural + metham sodium. In the first trial, all treatments reduced the populations of soilborne plant pathogens, including Pythium spp., Phytophthora spp., and Fusarium oxysporum, except for sodium, which did not reduce the population of Phytophthora spp. In the second trial, all treatments controlled Pythium spp. but only a high rate of iodomethane + chloropicrin reduced the population of F. oxysporum. For all treatments, the incidence of disease caused by soilborne pathogens was reduced compared to the nontreated control. The number and value of harvested rhizomes were greater among all of the treatments, except for sodium azide, compared to the control. The harvested value of the crop for the best treatments increased significantly compared to the control. A successful crop of calla rhizomes can be produced by combinations of iodomethane, chloropicrin, 1,3-dichloropropene, and metham sodium.
Junne-Jih Chen, Ming-Chung Liu, and Yang-Hsiu Ho
Tuber production of calla lily (Zantedeschia elliottiana Spreng cv. Super Gold) was investigated using three size ranges (7-10, 4-7, and <4 mm shoot diameter) of in vitro plantlets acclimated in either pots or soil beds in a protected house. The shoots and tubers of large plantlets exhibited higher rates of dry-matter accumulation than did those of small plantlets. The diameter of tubers harvested from pots ranged from 0.67 to 4.1 cm with median values of 2.7, 2.1, and 1.9 cm for the plants derived from large, medium, and small plantlets, respectively. Plants grown in soil beds, regardless of size, produced larger tubers than did those grown in pots. Tubers >3 cm in diameter developed on 25% and 52% of plants grown in pots and soil beds, respectively. Our results suggest that improved calla lily production could be realized by using larger in vitro plantlets as the source material and growing them in soil beds in a protected house.
Yulan Xiao and Toyoki Kozai
A photoautotrophic or sugar-free medium micropropagation system (PAM) using five large culture vessels (volume = 120 L each) with a forced ventilation unit for supplying CO2-enriched air was developed and applied to commercial production of calla lily (Zantedeschia elliottiana) and china fir (Cunninghamia lanceolata) plantlets. The culture period of calla lily plantlets in the PAM was reduced by 50%, compared with that in a conventional, photomixotrophic micropropagation system (PMM) using small vessels each containing a sugar-containing medium. Percent survival ex vitro of calla lily plantlets from the PAM was 95%, while that from the PMM was 60%. The production cost of calla lily in the PAM was reduced by about 40%, compared with that in the PMM, and the initial investment per plantlet for the PAM was ≈10% lower than that for the PMM. The sales price of ex vitro acclimatized calla lily plantlet was increased by 25% due to its higher quality, compared with plantlets produced in the PMM.
Julie A. Plummer, T. Eddie Welsh, and Allan M. Armitage
Zantedeschia aethiopica (L.) K. Spreng. `Childsiana' is a dwarf white calla lily with potential for pot culture. Nine stages of flower development from macrobud to senescence were described and shelf life under a low-light postproduction environment was examined. Flowers at the macrobud stage opened in the postproduction environment. Plants with flowers at the macrobud stage (Stage 1) and plants with spathes fully opened but before pollen shed (Stage 5) had shelf lives of 26 and 11 days, respectively.
Theo J. Blom and Wayne Brown
Four sterilants-bactericides (Physan-20, Fixed Copper, Phyton-27, and Virkon) were compared as preplanting dips of Zantedeschia elliottiana Engl. W. Wats `Yellow' (a susceptible cultivar) rhizomes to reduce plant losses due to latent field-infected Erwinia carotovora soft rot during greenhouse forcing as a flowering potted plant. All sterilant solutions were prepared in combination with Promalin, a commercially available product containing gibberellic acid (GA) used to enhance flowering. An additional group of rhizomes was inoculated with E. carotovora sp. as a preplanting dip in combination with the GA treatment but were not treated with a bactericide. Rhizomes were wounded by making two cuts on the distal part of the rhizome or left unwounded before application of the preplant dip treatments. After potting, plants were fertilized with either a high (3.0 mmol·L-1) or a low (1.0 mmol·L-1) calcium nutrient solution through subirrigation. More than 90% of the inoculated rhizomes collapsed within 5 weeks after potting due to bacterial soft rot. With the uninoculated rhizomes, the copper-based compounds (Fixed Copper or Phyton-27) provided better control of bacterial soft rot than either Physan-20 or Virkon only during the first 6 weeks of forcing. During the remainder of the forcing period, there were no differences in weekly losses of rhizomes with the four sterilants. Confirmation of Erwinia carotovora subsp. carotovora (Jones) Bergey et al. as the causal organism was made throughout the experiment. Incisions on the rhizome before planting or calcium nutrition during forcing did not have any significant effect on disease severity. Rhizomes treated with solutions of the copper-based compounds produced 0.5 flowers less per rhizome than either Physan-20 or Virkon. High calcium fertilization resulted in an increase of 0.5 flowers per plant compared to low calcium nutrition.
Ramona A. Reiser and Robert J. McGovern
Zantedeschia elliotiana `Flame' is a yellow calla with unique rust-colored blush, which is prone to a fungal/bacterial disease complex. Keeping calla rhizomes healthy and free of weakening by the most common fungal organisms Fusarium and Rhizoctonia, which minimizes secondary invasion and toppling by Erwinia carotova soft rot, the most prevalent cause of calla loss in production. Rhizomes were treated by pre-plant bulb dip or post plant drench either with fungicide or bactericide alone or in combination. Pot loss totaled with plants showing a lack of vigor resulted in 8%, 12%, and 14% loss in the most effective three treatments, which were: 1) the common commercial pretreatment (Champ II, Dithane, and Agtrol) 2) control plants and 3) RootShield (Trichoderma harzianum T-22). Upper (leaf and stem) plant fresh weights corresponded having heaviest weights of 47.8, 53.4, and 51.1 g and lower (bulb and root) with 129.5, 135.8, and 127.7 g/plant. The three least-effective treatments were streptomycin sulfate, Kocide 101, and ammonium bicarbonate, which showed losses of 26%, 30%, and 36%. Fresh weights coincided at 30.5, 39.9, and 36.7 g/upper portion and 117.1, 116.5, and 113.1 g/lower portion, lightest of all treatments. The remaining four fungicides with streptomycin sulfate, in order of effectiveness at 16%, 16%, 18%, and 20% loss, were Consyst, Banrot, Medallion, and Heritage. When loss exceeded 20%, flower number/plant also declined. Because plant survival and vigor were not increased with trial chemicals, the common commercial pretreatment or no treatment at all is recommended. Continued research might reveal beneficial optimum rates for other chemicals.
Brian E. Corr and Richard E. Widmer
The influences of irradiance level, day length, temperature, and leaf area on growth and flowering of Zantedeschia elliottiana Engl. W. Wats (yellow calla lily) and Z. rehmannii (pink calla lily) were determined. Plants grown with 45% or 15% of natural irradiance were taller than those grown under full natural irradiance but flowered at the same time and produced a similar number of flowers. Leaf removal treatments had no effect on any characteristic measured. Plants grown with a night interruption (NI; 2200 hr to 0200 hr) were taller than those under short days (SD = 8 hours), but flowered at the same time and produced a similar number of flowers. Plants were grown with air at 15 or 20C in combination with medium temperatures at ambient level (1C less than air temperature) or a constant 20 or 25C. Z. rehmannii grown with the medium at 20 or 25C and air at 1.5 or 20C flowered faster and were taller than plants grown with air at 15C and with the medium at ambient temperature, but plants from all temperatures produced the same number of flowers over a 120-day cycle. When plants grown with a NI in the first cycle were replanted and grown through a second cycle, they were taller than plants grown from SD treatment first-cycle plants. No first growth-cycle treatment influenced flowering in the second growth cycle.
I thank Judy Laushman for her assistance; Yoder Bros, Alva, Fla., for financial support of this work; and Ball Seed Co.. West Chicago. Ill.. and Barrie MacKenzie, B.L. MacKenzie Horticulture, New Zealand, for supplying the anemones and calla