Variation in 14 horticultural traits of native octoploid Fragaria L. from North and South America was examined in a greenhouse. Significant levels of variation were found for all but a few of the traits at the species, subspecies, regional and genotypic level, with the highest amount of variation generally being partitioned among genotypes. Fragaria chiloensis (L.) Miller was superior to F. virginiana Miller for crown number, fruit weight, soluble solids and seed set, while Fragaria virginiana was superior for runner production, peduncle length, fruit number, fruit color and winter hardiness. Fragaria chiloensis ssp. pacifica Staudt had the highest soluble solids and among the earliest bloom dates, highest crown numbers and highest seed set. Fragaria chiloensis ssp. chiloensis f. chiloensis (L.) Duch. produced the largest fruit and among the earliest bloom dates and longest peduncles. Fragaria chiloensis ssp. chiloensis f. patagonica (L.) Duch. had among the highest crown numbers and the highest percentage seed set. Fragaria virginiana ssp. platypetala (Rydb.) Staudt produced the most crowns and its fruit ripened earliest. Fragaria virginiana ssp. glauca (Wats.) Staudt were the latest flowering, had the darkest fruit color and the most flowering cycles. Fragaria virginiana ssp. virginiana Duch. displayed the most winter dieback, the longest peduncles, and the highest flower and runner numbers. No significant differences were observed in any of the examined traits between F. chiloensis ssp. pacifica and F. chiloensis ssp. lucida, or F. virginiana ssp. grayana and F. virginiana ssp. virginiana. A number of individual genotypes were superior for more than one trait. CFRA 0024 possessed unusually high crown numbers, was extremely early blooming and displayed multiple fruiting cycles. CFRA 1121 had unusually long peduncles and much higher than average values for fruit weight, soluble solids, fruit color and seed set. CFRA 0094 was extremely early flowering and had much darker fruit color than most other F. chiloensis genotypes. CFRA 0368 flowered unusually early and had among the largest fruit. CFRA 0366 possessed unusually long peduncles and the largest fruit of any North American genotype. CFRA 0560 and CFRA 1369 had an unusual combination of multiple flowering cycles and high runner production. CFRA 1170 and 1171 were unusually late fruiting and had high numbers of large fruit on long peduncles. CFRA 1385 and JP 95-3-1 had extremely high flower numbers, long peduncles and large fruit.
capable horticultural technicians to care for the most problematic species. Therefore, empirical research results are a prerequisite to managing this aspect of a conservation nursery. Several tree species that are native to the Mariana Islands are
Germination of purple sage [Salvia dorrii (Kellogg) Abrams] seed was evaluated under 21 temperature combinations (day temperatures from 5 to 30C and night temperatures from 5 to 30C) in two experiments: 1) cool-moist stratification; and 2) sandpaper scarification, leaching with water, or gibberellic acid (GA3). The quadratic responses of weighted germination percentage (WGP), a combined index of germination percentage and speed of germination, were significant (P ≤ 0.05) for all treatments. The interaction of day and night temperatures was significant (P ≤ 0.05) only for the 2-week stratification treatments and for the Expt. 2 control. Stratification increased WGP over the control. Optimal WGP for all stratification treatments ranged from 46% to 51%. Optimal WGP was the same for both GA3 treatments. Optimal WGP for 0.29 mmol GA3 occurred at 16C night temperature and 22C day temperature, and for the 1.44 mmol GA3 treatment at 18C night and at 30C day temperature.
Scarification treatments (a control, a 10-minute vacuum, or a 1.5-minute ultrasound), different media (modified Norstog and Van Waes) and growth regulators [benzyladenine (BA) at 0, 1, 1.5, or 2 mg·L-1 and 6-(r,r-dimethylallylamino)-purine riboside (2iPR) at 0, 1, 1.5 or 2 mg·L-1] were used in combination to increase seed germination of Cypripedium calceolus var. parviflorum. Seeds treated with ultrasound had higher germination (58.0%) than those treated with vacuum (27.4%) or controls (19.2%). Germination rates increased with 2iPR level and reached a maximum between 1.5 and 2 mg·L-1. Seeds on Van Waes medium, which were not transferred to fresh medium after germination, had a severe browning problem causing many protocorms to die. Those on Norstog medium continued to grow into seedlings with less browning. Germination rates of Calopogon tuberosus × Calopogon `Adventure' and Liparis liliifolia were determined on the different media and growth regulator treatments. Multiple shoots of Calopogon developed from single seeds on media containing growth regulators. Flower buds formed in vitro on Calopogon in media containing 1 mg·L-1 or higher BA 5 months after germination. L. Iiliifolia seeds in Norstog medium had a higher proportion of germination than those in Van Waes medium.
The effect of cold on germination rate, percentage and range of five cut flowers was investigated: Baptisia australis (Wild Blue Indigo), Echinacea purpurea (Purple Coneflower), Helianthus maximilianii (Maximillian Sunflower), Solidago petiolaris (Spike Goldenrod), and Vernonia missurica (lronweed). Viability was determined for the species using TTC staining and germination based on percent viable seed. Seeds were given 0, 2, 4, 6, 8, or 10 weeks of cold at 5°C. Increasing weeks of cold decreased days to germination in all five species, with Baptisia demonstrating the greatest effect. The germination percent increased as weeks of cold increased in all five species, but was most significant in Helianthus and Vernonia. Days from first to last germinating seed was significantly decreased in all five species as weeks of cold increased. Four weeks of cold was optimum for Echinacea and Vernonia, while optimum weeks of cold for Helianthus and Solidago was six weeks and Baptisia ten weeks.
Rhamnus alnifolia and Rhamnus lanceolata are shrubs of modest size with lustrous foliage. We evaluated seed germination of both species and propagated R. alnifolia by using softwood cuttings collected in early June. For R. alnifolia, cold stratification for up to 90 d resulted in 48% germination and a germination value of 1.9, whereas only 7% germination occurred among seeds stratified for 120 d. Seeds of R. alnifolia did not germinate if they were untreated or if scarified and stratified. Rhamnus lanceolata required 120 d of stratification to germinate, but percentages were low (≤ 5). Survival of germinants of both species was 90 to 100% regardless of prior seed treatment. Seedlings grew uniformly and had a mean leaf count of 11 and a mean height of 20 cm after 102 d. Application of 3000 and 8000 mg/L indole-3-butyric acid (IBA) in talc led to 85% rooting of R. alnifolia, whereas rooting was ≤ 15% after use of solutions with those IBA concentrations. While 75% of untreated cuttings rooted, fewer roots formed without IBA. More roots developed in 100% vermiculite than in 1 vermiculite: 1 perlite (by volume), which also diminished the number and apparent health of leaves on cuttings during the rooting period. We conclude that talc-based IBA and vermiculite should be used to root softwood cuttings of R. alnifolia, and that both species can be propagated from stratified seeds. Rhamnus lanceolata is more recalcitrant than is R. alnifolia and merits further study to optimize germination success.