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Introduction

Eastern redcedar (Juniperous virginia L.)is a traditional Christmas tree species commonly planted in North Carolina. Visit the National Christmas Tree Association Web site for a further description of Eastern redcedar. This species makes an ideal candidate for clonal Christmas tree production. Unlike pine species, eastern redcedar roots readily at the ages of concern for Christmas tree production. Further, maturation effects on the growth and development of rooted cuttings appear to be negligible. Many cultivars (clones) of eastern redcedar exhibiting a wide variety of growth habits and colors have been propagated in the horticultural industry for years. Although eastern redcedar is an important Christmas tree species, the relatively small number of trees planted each year makes it difficult to justify a large-scale breeding program for this species. However, clonal screenings within the currently used planting stock can serve to provide growers with uniform and superior planting stock for the near future. Later, if new clonal material is desired, screening of other sources of redcedar or of hybrids with other Juniperus species may be undertaken.

Clonal Testing

Christmas tree plantations of seven interested growers (Table 1) were searched for select trees early in 1997. Thiry-two individual tree selections were made. Measurements were taken for each selection and 5 surrounding check trees.

Grower County

# Selections

Snodie Wilson Pitt

4

David Corn Granville

4

Eric Cobb Guilford
Prince William (VA)

7
5

Jack Rich Edgecombe

2

Dorsey Daniel Harnett

3

Dan McInnis Johnston

5

Whit Jones Duplin

2
(3 ages each)

Total  

32

Table 1. Grower and location (county) of North Carolina Eastern redcedar selections.

Trees which are outstanding in any of the following four categories were candidates for the clonal testing program: 1) growth and form, 2) color, 3) foliage softness, or 4) resistance to Phomopsis blight. Selection criteria for each of the four traits of interest are outlined in Table 2.

One selection criteria was apparent resistance to Phomopsis blight. This disease of eastern redcedar is caused by the fungus Phomopsis juniperovora Hahn. Its primary symptom is browning and death of branches. This browning usually begins on branch tips and progresses toward the stem of the tree. The fungus can completely kill seedlings and small trees by infecting the stem and girdling it with dead tissue. Although its extent is not currently known, several growers are having severe problems with this disease in their Christmas tree plantations. To be effective, selection of disease-free trees must occur in plantation with a high incidence of the disease.

Selection Trait

Criteria

Growth & Form

-- exceeds or equals height of the 30 nearest trees
-- pest-free
-- premium quality form (not-cigar shaped)
-- good color

Foliage Color

--  pleasing color either before or after artificial coloring
--  equals or exceeds mean height of the nearest 30 trees
--  pest-free
--  premium quality form (not-cigar shaped)

Foliage Softness

 

-- less than 5% of foliage is of juvenile (prickly) type
-- equals or exceeds mean height of the nearest 30 trees
-- pest-free
-- premium quality from (not cigar-shaped)

Resistance to Phomopsis Blight

-- pest-free
-- at least 80% of the nearest 30 trees have Phomopsis blight
-- premium quality form (not cigar-shaped)
-- good color

Table 2. Selection criteria for four traits of interest in the North Carolina eastern redcedar clonal program.

The selections were rooted in a propagation greenhouse at the NCSU Horticultural Field Laboratory during 1997. Average rooting percent was 66% with individual clones ranging from 16 to 98%. (See Eastern Redcedar Rooting Study for more details.)

In early summer of 1998, these rooted cuttings were potted into larger containers for outdoor culture. In the future, multiple copies of each clone will be represented in each of three clonal tests. These tests will be measured annually. Rooted cuttings of all clones will be archived in a clone bank. A protocol will be developed for making cutting material available to North Carolina growers and nursery producers interested in developing hedge orchards of the most promising clones for their own rooted cutting production. A proposed schedule of activites for the Eastern redcedar clonal propagation program is presented in Table 3.

Date

Activity

1997

Selected 32 trees in Christmas tree plantations
Rooted 100+ cuttings / selection

1998

Transplanted rooted cuttings into pots
Cultured cuttings outdoors

1999

Root cuttings for clonal archive
Establish clonal field trials
1st year field measurements

2000

Start production hedge orchard
2nd year field measurements

2001

Continue hedge orchard development
3rd year field measurements
Table 3. Proposed schedule for Eastern redcedar clonal propagation program.

Proceed to Eastern Redcedar Rooting Study

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