: breaking dormancy, increasing stem length, and reducing production time ( Naranja and Balladares, 2008 ). Because GA 3 effects can vary greatly among different taxa, the objective of these trials was to quantify the effects of GA 3 on cut stem production
Ben A. Bergmann, John M. Dole, and Ingram McCall
H. Chris Wien
The stems of many flower species used as cut flowers are too short to be commercially useful. Non-chemical techniques are needed to increase the length of the harvested stems without weakening stem strength. Field experiments were conducted that explored the use of black or red shade fabric, used either as a canopy, or as a side curtain, with three species of cut flowers. Trachelium caerulum, Eustoma grandiflorum (Echo Champagne), and Rudbeckia hirta (Prairie Sun) were grown in split-plot experiments in which shade and shelter treatments were applied as main plots, and the flower species formed the subplots. In 2004, shade canopies of 70% light transmission were compared in black and red (“ChromatiNet”) netting, and 50% red netting. Stem length increased from 51 cm for unshaded controls to 54, 56, and 59 cm for 70% black, red, and 50% red, respectively. Productivity of the plants was decreased an average of 21% by shading. In 2005, shade canopies of 50% black or red were compared to side curtains of the same materials, and an unsheltered control, growing the same species of flowers. Stem length was increased by 25% when plants were grown under a shade canopy, and by 14% in the side curtain plots. Shading treatments reduced stem yield by 31%, whereas side curtains had no significant effect on number of stems per plant. Color of the netting did not affect stem length or stem yield in 2005. In both years, the thickness of harvested stems were increased significantly in the shelter treatments. The three species reacted similarly to the treatments imposed in both years. Shelter treatments can be a practical way of increasing cut flower stem length.
Joseph N. Wolukau, Xiaohui Zhou, and JinFeng Chen
long and/or girdling of stem; 4, stem withered; and 5, seedling dead. Plants that received a rating of 1 or 2 were considered resistant and those greater than 3 were susceptible. DNA isolation, bulk segregant analysis, and amplified fragment length
John M. Dole, Janet C. Cole, and Vicki Stamback
Rooted cuttings of four woody cut species, Buddleia davidii `Black Knight' (butterfly bush), Forsythia × intermedia `Lynwood Gold', Salix chaenomeloides (Japanese pussywillow), and Salix matsudana `Tortuosa' (corkscrew willow) were planted outdoors in 23 Apr. 1992. During the next year, forsythia, pussywillow, and corkscrew willow plants were either unpruned or pruned to 30–45 cm above the ground: 1) during dormancy or immediately after harvest (winter); 2) 3 to 4 weeks after start of shoot growth (spring); or 3) in early June (summer), and number and length of stems harvested was recorded for three years. Butterfly bush was either unpruned or pruned to 8 cm above the ground during: 1) winter or 2) spring, and number and length of stems recorded for 2 years. Stem length and number increased each year for all four species, and all species produced harvestable stems within 1 year after planting. For forsythia, no differences due to treatment were found, although year by treatment interactions were noted. The unpruned control produced the longest and greatest number of stems for pussy willow. Winter or spring pruning produced the longest and greatest number of stems for corkscrew willow. For butterfly bush, spring or no pruning produced the greatest number of stems, and year by treatment interactions were noted.
Various field-grown specialty cut-flower species were subjected to full sun or 55% or 67% shade treatments for 2 to 3 years. Plants grown in shade had longer flower stems than those grown in ambient irradiance; however, yield (flower stems per plant) was species-dependent. Yield of Centaurea americana Nutt. `Jolly Joker', an annual speices, and Eryngium planum L., a perennial, declined linearly with each reduction in irradiance. However, yield of Echinops ritro L. `Taplow Blue', a perennial species, was higher in 55% shade than in ambient irradiance. Yield of transplants and tubers of Anemone coronaria L. `De Caen' were not affected by planting material (transplants or tubers). Plants grown under 67% shade had the longest stems starting 3 weeks after the beginning of harvest and the difference persisted for an additional 4 weeks regardless of planting material. A quadratic decline in yield in three of four cultivars of Zantedeschia Spreng. occurred as shade increased, but yield was similar for ambient and 55% shade. Scape length and spathe width increased as shade increased, although some cultivars were more responsive than others.
Douglas A. Hopper
Height data were collected three times weekly between pinch and flowering to represent `Royalty' rose (Rosa hybrida L.) response to 15 unique treatment combinations of irradiation as photosynthetic photon flux (PPF: 50 to 300 μmol·m-2·s-1), day temperature (DT: 12 to 22 °C), and night temperature (NT: 15 to 25 °C) under constant growth chamber conditions. Combinations were determined according to the rotatable central composite design. A previous full quadratic model approach was compared with a revised approach using a nonlinear Richards function derivative form. This allowed a dynamic change of parameter values for each daily growth iteration by computer. The Richards function assumes nonconstant daily growth rates are proportional to current size; Euler integration enabled additive accumulation of these values. Ratios of the growth constant (k) to the theoretical catabolic constant (m = v+1) caused flexible changes in the growth curve, which were compared with the previous quadratic approach.
James M. Garner and Allan M. Armitage
increase length of the flowering stems ( Iversen, 1989 ; Iversen and Weiler, 1994 ). The objective of these investigations was to determine the influence of cooling on the number of greenhouse days to flower, flowering stem length, and yield of cut flower
Alicain S. Carlson and John M. Dole
( Rees, 1974 ). Increasing planting density to increase productivity per unit area can decrease the productivity per plant, increase stem length, and increase earliness of flowering depending on the species ( Rees, 1974 ). Higher rates of transpiration
Margaret M. Saska and Yulia A. Kuzovkina
for floral cut-stem market sales. Market prices of willow stems are determined by stem length with longer stems commanding higher market prices. When sold by length, stems may be offered as single-stemmed whips or as branched stems ( Greer and Dole
Crofton Sloan and Susan S. Harkness
accomplished by the evaluation of plant growth parameters such as the number of stems produced per plant, stem length, and harvest period of the cultivars. The two series were chosen for this trial because they were promoted as fragrant, cut flower roses for