Amphidiploid Dendrobium Mini Gem, a hybrid with two sets of chromosomes each of D. bigibbum var. compactum of the section Phalaenanthe (P. genome) and the diminutive D. carronii of the section Eleutheroglossum (E. genome), has been utilized successfully in our breeding program to produce miniature, seed-propagated, potted plant cultivars. D. Cathy Beck (UH1221) released earlier is a cross between D. Mini Gem and D. antennatum of the section Ceratobium (C. genome), and has the PCE genome constitution.

Two additional hybrids of amphidiploid D. Mini Gem have performed well, and therefore are being named and released for commercial cropping as potted plants. These are D. Betty Nakada (UH1208) and D. Remy Hartmann (UH1307).

D. Remy Hartmann is a hybrid of amphidiploid D. Mini Gem and D. stratiotes of the ceratobium (Spatulata) section. Its pedigree is similar to that of D. Cathy Beck with the exception of the D. stratiotes parent instead of D. antennatum.  The cross was made on April 9, 1988, and germinated on July 5, 1988. Seedlings were transflasked on Other 11, 1988, compotted in February 1989, potted in 2-inch pots in July 1989, and repotted in 5-inch plastic pots in January 1990. A few seedlings started to flower in March 1990 (Fig. 1), only 20 months after germination, but peak flowering was obtained from October through March 1990.

The characteristics of D. Remy Hartmann are presented in Table 1. The flowers are about 2-1/4 inches across with relatively narrow sepals and petals. The petals are purple (RHSCC 78A) and the sepals are lighter purple (RHSCC 78B) with white edges and reflexed. Due to the influence of D. stratiotes, the plants are taller than D. Betty Nakada. Pseudobulb height at first flower was about 6.5 inches, and after peak flowering in April 1991 was only 9.1 inches. Two years later the average height was 17.6 inches, still an acceptable height as a potted plant. The pseudobulbs are sturdy and upright.

The major attributes of D. Remy Hartmann are prolific flowering, good seasonality and early flowering producing marketable plants within three years from germination. The narrow green leaves on erect pseudobulbs with numerous flower sprays make attractive potted plants.

Characteristics

D. Betty Nakada

D. Remy Hartmann

Scape length (inches)

7.1 ± 1.3

5.0 ± 0.9

Spray length (inches)

12.2 ± 3.6

11.8 ± 2.1

Number of flowers per spray

10.5 ± 5.4

11.3 ± 4.0

Flower length (inches)

1.3 ± 0.2

1.7 ± 0.1

Flower width (inches)

1.7 ± 0.3

2.3 ± 0.2

Pedicel length (inches)

1.2 ± 0.3

1.0 ± 0.1

Percent bud drop

6.4 ± 11.2

6.5 ± 6.1

Leaf length (inches)

4.8 ± 0.5

5.5 ± 0.3

Leaf width (inches)

1.2 ± 0.1

1.5 ± 0.1

Pseudobulb height to first flower (inches)

1.9 ± 0.6

6.6 ± 1.6

Pseudobulb height at termination (inches)

10.0 ± 1.4

17.6 ± 4.0