Effect of variegation on growth and chilling sensitivity of 'Marble Queen' Pothos

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A. R. Chase and R. T. Poole*

University of Florida, IFAS
Central Florida Research and Education Center - Apopka
CFREC-Apopka Research Report, RH-90-17

Many foliage plants are prized for their variegated leaves which add visual interest. Epipremnum aureum (pothos) has been grown for many years and several cultivars have been developed which range from solid green ('Green Gold') to variegated with yellow ('Golden Pothos') or white ('Marble Queen'). Although these cultivars were generated from the solid green form, they possess differences in cultural requirements for optimal growth related to the degree of variegation. Preliminary work on chilling sensitivity (50F) indicated that 'Marble Queen' plants were more sensitive than their greener relatives. This report summarizes experiments performed to evaluate the effect of variegation on growth and chilling sensitivity of 'Marble Queen' pothos.

Methods

Two tests were performed between January and July 1990 utilizing about 50 'Marble Queen' plants each. Plants in 3" pots were established in Vergro with 6 g Sierra (17-6-12) with minors/6" pot and grown on a greenhouse bench for 2 months. They were watered 2-3 times/week as needed and received 1500 to 3000 ft-c. (maximum) depending upon time of year. At the end of the growth period, they were then graded for degree of variegation from 1 (all white) to 5 (all green). Number of leaves, number of vines greater than 6 inches in length and total vine length were determined at this time as well. Plants were then subjected to chilling conditions for 1 week at 50F by placing them in temperature control chambers. One week after the chilling treatment was completed, the number of leaves with necrosis was determined. Correlations between the variegation rating and other data were made statistically.

Results And Discussion

Although the degree of variegation differed between the two tests, the majority of plants (69 - 74% ) in each test were rated from 2.5 to 3.5 (very good quality 'Marble Queen', based on color and form). The mean number of leaves, vines and total vine length was influenced by the degree of variegation in at least one of the two tests (Table 1 and 2). Plant growth as measured by these parameters, increased as the degree of variegation (white tissue) decreased. That is, the green plants grew better than the white ones. In addition, the whiter the plant the more severe the damage incurred from exposure to chilling conditions.

It was interesting to note how different individual pots of 'Marble Queen' could be from each other when they were obtained from a single source. Growers are advised to carefully select plants for stock to eliminate those which are too white since they grow more slowly than those which are greener and are more sensitive to chilling injury. Cuttings appeared the same when obtained and developed this range of variegation only after 2 months of growth, the problem for growers who purchase cuttings may be severe because as many as one third may be unacceptable.


*Professors of Plant Pathology and Environmental Horticulture, respectively. Central Florida Research and Education Center, 2807 Binion Rd., Apopka, FL 32703-8504.


Table 1. Effect of color on growth and sensitivity to chilling at 50F for 1 week for Epipremnum aureum 'Marble Queen' (Exp. 510 - 30 January to 17 April 1990).
Color
Gradea
# Observations
(percent)
Mean #
leaves
Mean #
leaves with
chilling
injury
Mean #
vines
2.0 6 (12%) 20.2** 8.3** 0**
2.5 8 (16%) 21.8 5.0 0.1
3.0 12(24%) 23.8 2.2 0.9
3.5 17(34%) 25.2 1.0 1.8
4.0 6 (12%) 27.2 0.8 1.5
4.5 1 (2%) 32.0 1.0 3.0
  1. aColor was graded on a scale from 1 (white) to 5 (green).
    **Significant at the 1% level within columns.

Table 2.Effect of color on growth and sensitivity to chilling at 50F for 1 week for Epipremnum aureum 'Marble Queen' (Exp. 541 - 18 April to 25 June 1990).
Color
Gradea
# Observations
(percent)
Mean #
leaves
Mean #
leaves with chilling injury
Mean # vines Mean #
vine
length
(cm)
2.0 1 (2%) 32.0ns 13.0** 0** 0**
2.5 9 (16%) 27.0 4.9 1.9 48.3
3.0 13(23%) 29.4 2.3 1.8 62.1
3.5 17(30%) 28.5 3.6 2.1 77.5
4.0 12(22%) 27.0 4.0 1.5 65.8
4.5 4 (7%) 27.5 3.8 2.2 113.2
  1. aColor was graded on a scale from 1 (white) to 5 (green).
    **Significant at the 1% level or not significant ns within columns.