Storage Temperature and Duration affect Propagation of Dracaena fragrans 'Massangeana'

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C.A. Conover, Ph.D.*

University of Florida/IFAS
Central Florida Research and Education Center
2807 Binion Rd
Apopka FL 32703-8504

CFREC-Apopka Research Report RH-94-2

Dracaena fragrans 'Massangeana' is usually propagated from cane pieces of varying lengths. The time required to grow from cane into salable plant material is variable for local growers, since root and shoot development and growth in Florida is much slower during the winter months. To better manage resources, growers need to know the effects of cane storage on propagation during both winter and summer.

In earlier research conducted during the winter, root and shoot growth of l-ft and 3-ft cane sections stored after shipping in coolers maintained at 40, 50, 60 or 70°F for 2, 4, 6 or 8 weeks were compared to a control group propagated in a greenhouse immediately after shipping (Conover and Poole, 1991). One-ft or 3-ft cane stored at 40°F for over 2 weeks was damaged and in unsalable condition after propagation. Rooting was improved on cane stored at 50, 60 or 70°F for up to 8 weeks compared to rooting of unstored cane.

However, as storage time increased, shoot length on l-ft cane decreased. Length of shoots on 3-ft cane stored at 50, 60 or 70°F for more than 4 weeks after propagation were also shorter than shoots on cane propagated without storage. Additional experiments were carried out to determine storage effects on propagation during the summer and to further refine optimum storage temperature and duration for 'Massangeana' cane.

Materials and Methods

These experiments were replicates of each other in all details except cane length. Experiment 1 used l-ft cane while experiment 2 used 3-ft cane. On July 30, 1991, unrooted l-ft and 3-ft cane, imported from Costa Rica, arrived at CFREC-Apopka. A control group was propagated immediately after arrival, without undergoing storage treatments. Cane was propagated in cypress shavings mounded around the cane bases on a greenhouse bench where maximum light intensity was 1500 ft-c and air temperatures ranged from 65 to 90°F. An intermittent mist system provided 5 minutes mist at 30 minute intervals from 12:00 noon until 4:00 pm daily. Remaining 'Massangeana' cane were stored upright in dark airtight coolers maintained at 60, 70, 80 or 90°F, for 2, 4, 6 or 8 weeks.

Cane were removed from temperature controlled storage at 2 week intervals starting on August 13, for cane stored 2 weeks and cane stored 8 weeks on September 23, 1991. After removal from storage, cane were propagated on the same greenhouse bench as the control group.

After 19 weeks of propagation, number of roots, root grade (based on 1 = no roots, 2 = little root system development and growth, 3 = average root system, 4 = good root system and 5 = excellent root system), number of shoots and total shoot length were determined. Final data was recorded for the control group on December 5, for cane stored 2 weeks on December 19, 1991, for cane stored 4 weeks on Jan 2, for cane stored 6 weeks on Jan 16 and for cane stored 8 weeks on Jan 30, 1992; thus, all cane remained on the propagation bench for the same length of time.

Results

Interaction of storage temperature and duration affected number of roots on l-ft Dracaena 'Massangeana' cane when counted 19 weeks after cane were placed in the propagation area (Table 1). Although number of roots on l-ft cane was somewhat variable, cane stored at 90°F for over 2 weeks or at any temperature except 80°F for longer than 6 weeks had less roots than others (Table 1).

Root grade of l-ft cane was also affected by interaction of storage temperature and duration (Table 2). Root grade of cane stored at 90°F decreased with each increase in storage duration. Root grade decreased after 4 weeks storage for cane stored at 80°F, and decreased after 6 weeks for cane stored at 60 or 70°F. One-ft cane produced less than 2 shoots per cane and shoots were much shorter on cane stored at 90°F for more than 2 weeks or at 80°F for over 6 weeks compared to other cane tested (Tables 3 and 4).

In experiment 2, interaction of storage temperature and duration affected root grade and total shoot length of 3-ft cane. Best quality root systems were in the control group, plants stored at 60 or 70°F for up to 4 weeks or at 80°F for 2 weeks (Table 5). When compared to shoot length of the control (122.6-cm), storage at any temperature and duration retarded shoot development (Table 6). Shoots were much shorter on cane stored at 90°F compared to cane stored at lower temperatures.

Total number of roots and shoots on 3-ft cane were not affected by interaction of storage temperature and duration. After propagation, 3-ft cane stored at 60, 70 or 80°F had produced over 20 roots and more than 2 shoots per cane, while cane stored at 90°F had less than 10 roots and 2 shoots per pot (Table 7). Cane stored over 4 weeks also had less than 20 roots per pot, but total number of shoots on 3-ft cane was not affected by time spent in storage.

Conclusions

For l-ft cane propagated in this test, root growth after up to 6 weeks storage at 60 or 70°F and shoot growth after storage for up to 8 weeks at 60 to 70°F was comparable to the unstored control group. Although storage retarded shoot length on 3-ft cane, root system development was mostly good on cane stored at 60, 70 or 80°F for up to 8 weeks.

In an earlier test, conducted during the winter/spring growing season, growth of 3-ft cane stored for up to 4 weeks at 60 or 70°F was comparable to unstored cane. However, overall growth and development of 3 ft-c cane was much slower during the earlier experiment, conducted during the cool season compared to cane growth in this test conducted during the summer months. In the earlier test, growth differences between stored and unstored cane may not have been significant because overall growth and development was retarded during the winter. In this test, shoot growth on 3-ft cane was retarded by any storage time tested. Growth retardation may have occurred because 3-ft cane was stored during August, a more active growing period.

When experimental results were compared, 1-ft cane growth and development was more variable within treatments compared to that of 3-ft cane. One of the biggest problems local growers are having with Dracaena 'Massangeana' is the variability of rooting and sprouting of 1-ft cane stored for any time during the winter.

In summary, these and previous experiments demonstrate that cane storage is possible for up to 8 weeks and best storage temperatures are in the 60 to 70°F range. However, some growth delay may be observed on stored cane compared to those propagated immediately. Delays may occur for 3-ft cane stored during the summer or cane stored for over 4 weeks during winter. One-ft cane growth may be retarded if cane is stored during the winter or if cane is stored for over 6 weeks during the summer.

Table 1. Interaction effects of storage temperature and duration on number of roots on 1-ft Dracaena fragrans 'Massangeana' cane 19 weeks after removal from storage. Experiment 1.

Interaction results significant at P = 0.0001.
Control group, which were propagated without undergoing storage averaged 16 roots per plant.

Table 2. Interaction effects of storage temperature and duration on root grade of l-ft Dracaena fragrans 'Massangeana' cane 19 weeks after removal from storage. Experiment 1.

Interaction results significant at P = 0.0001. Average root grade of the control group, which did not undergo storage, was 4.8.
^zRoot grade based on a scale of 1 = no roots, 2 = little root system development and growth, 3 = average root system, 4 = good root system and 5 = excellent root system.

Table 3. Interaction effects of storage temperature and duration on number of shoots produced on l-ft Dracaena fragrans 'Massangeana' cane 19 weeks after removal from storage. Experiment 1.

Interaction results significant at P = 0.0052. The control group, which did not undergo storage, averaged 2 shoots per plant.

Table 4. Interaction effects of storage temperature and duration on total length (cm) of shoots produced on l-ft Dracaena fragrans 'Massangeana' cane 19 weeks after removal from storage. Experiment 1.

Interaction results significant at P = 0.0001. Average total shoot length of the control group, which did not undergo storage, was 59.0 cm.

Table 5. Interaction effects of storage temperature and duration on root grade of 3-ft Dracaena fragrans 'Massangeana' cane 19 weeks after removal from storage. Experiment 2.

Interaction results significant at P = 0.0001. Average root grade of the control group, which did not undergo storage, was 5.0.

^zroot grade based on a scale of 1 = no roots, 2 = little root system development and growth, 3 = average root system, 4 = good root system and 5 = excellent root system.

Table 6. Interaction effects of storage temperature and duration on total length (cm) of shoots produced on 3-ft Dracaena fragrans 'Massangeana' cane 19 weeks after propagation. Experiment 2.

Interaction results significant at P = 0.0417. Total shoot length of the control group, which did not undergo storage, averaged 122.6 cm.

Table 7. Effects of storage temperature and duration on total number of roots and shoots on 3-ft Dracaena fragrans 'Massangeana' cane 19 weeks after removal from storage. Experiment 2.

The control group, which did not undergo storage, averaged 26.8 roots and 2.8 shoots per cane.
^zns = Results nonsignificant, * = significant at P = 0.05, ** = significant at P = 0.01.

*professor of Environmental Horticulture and Center Director (retired 7/96), Central Florida Research and Education Center, 2807 Binion Rd., Apopka, FL 32712-8504.

Reference

Conover, C. A. and R. T. Poole. 1991. Storage time and temperature affect growth of Dracaena fragrans 'Massangeana'. Proc. Fla. State Hort. Soc. 104:331-333.