Dormant-budded `Gloria' azaleas (Rhododendron sp.) at various maturity levels (one, eight, or 32 individual open flowers) were moved from the greenhouse to postproduction rooms. Postproduction rooms were maintained at 21 ± 1C, relative humidity 50% ± 5%, and 12 hours of daily irradiance at 12 μmol·s–1·m–2 from cool-white fluorescent lamps to simulate home conditions. Using predetermined categories, the number of tight, showing-color, candle, and open-flower inflorescences were recorded. After 2 weeks postproduction, plants chosen at the start of postproduction with eight or 32 individual open flowers had the best flowering uniformity and flower color. In a second experiment, azaleas with one, eight, or 32 individual open flowers were placed into simulated transport for 4 days at 16 ± 1C. Plants with one individual open flower had greatest longevity, but those with eight open flowers had the best overall postproduction performance. In a final experiment, azaleas at similar maturity levels were placed in simulated transport at 5, 16, or 27C for 2, 4, or 6 days. After 2 weeks postprodudion, there was no difference due to simulated-transport temperature or duration on flowering performance or flower color. Longevity was good for plants held 2, 4, or 6 days at 5C and for plants held for 2 days at 16 or 27C.
Lori A. Black, Terril A. Nell, and James E. Barrett
Tae-Ho Han, Herman J. van Eck, Marjo J. De Jeu, and Evert Jacobsen
An F1 population, derived from an intraspecific cross between two Alstroemeria aurea accessions, was used to map quantitative trait loci (QTL) involved in ornamental and morphological characteristics. One QTL for leaf length was mapped on linkage group three of both parents near marker E+ACCT/M+CGCA-I165 explaining 20% and 14.8% phenotypic variation. Two putative QTL were detected on leaf width on A002-3 and A002-6. One QTL and three putative QTL, involved in the leaf length/width ratio were identified accounting for 46.7% of the phenotypic variance in total. Significant interaction was observed between two QTL, S+AC/M+ACT-I162 and S+AC/M+AGA-I465 in a two-way analysis of variance (ANOVA). For the main color of the flower one QTL and putative QTL accounted for up to 60% of phenotypic variance suggesting simple genetic control of flower color. A two-way ANOVA of these QTL suggested an epistatic interaction. A QTL was detected for color of the inner side of outer lateral tepal with 26.5% of the phenotypic variance explained. This QTL was also associated with main color of the flower just below the 95% threshold value. Two QTL were detected with the Kruskal-Wallis test for the tip color of inner lateral tepal near QTL for other flower color traits. Consequently flower color traits were significantly correlated. A QTL and a putative QTL for the flower size was mapped near marker E+ACCG/M+CGCT-I193 and E+ACCG/M+CGCG-197, respectively. One putative QTL was detected for the stripe width of the inner lateral tepal.
Mark W. Farnham and Thomas Björkman
recorded for calculation of the mean number of days from transplant to harvest (DTH) on a plot basis. In addition to this sampling, horticultural traits (i.e., head color, shape, smoothness, firmness, bead size, bead uniformity, and overall quality) were
R.J. Griesbach and R.A. Waterworth
Recently, several new Calibrachoa La Llave & Lexarza cultivars have been developed with novel red and blue flowers. Most of the wild species of Calibrachoa have purple flowers. The difference in color between the red, blue, and purple flowers was not due to anthocyanin composition but to vacuolar pH. The pH of the red flowered cultivar was 4.8, while that of the blue flowered cultivar was 5.6. The wild purple flower species had an intermediate pH of 5.0. The difference in pH was genetically inherited.
S. Rajapakse, L. E. Belthoff, R. E. Ballard, R. Scorza, W.V. Baird, R. Monet, and A. G. Abbott
We have constructed a genetic linkage map of peach consisting of RFLP, RAPD, and morphological markers, based on 78 F2 individuals derived from the self-fertilization of four F1 individuals originating from a cross between `New Jersey Pillar' and KV 77119. This progeny set was chosen because parental genotypes exhibit variation in canopy shape, fruit flesh color, and flower petal color, size, and number. The segregation of 81 markers comprised of RFLP, RAPD and morphological loci was analyzed. Low copy genomic and cDNA probes were used in the RFLP analysis. The current genetic map for the WV family contains 57 markers assigned to 9 linkage groups, which cover 520 cM of the peach nuclear genome. The average distance between two adjacent markers was 9 cM. Linkage was detected between Pillar (Pi) and double flowers (Dl). RFLP markers loosely linked to Pi, flesh color (Y), and white flower (W) loci were found. Twenty-four markers remain unassigned.
Susan S. Han
Publication no. 3299 of the Massachusetts Agr. Expt. Sta. I thank Montgomery Rose, in Hadley, Mass., for donation of the cut flowers and the Association of Specialty Cut Flower Growers and the New England Greenhouse Conference for partially
Rasika G. Mudalige, Adelheid R. Kuehnle, and Teresita D. Amore
Perianths of 34 Dendrobium Sw. species and hybrids were examined to elucidate the roles of pigment distribution and shape of upper epidermal cells in determining color intensity, perception, and visual texture. Color intensity was determined by the spatial localization of anthocyanin in tissue layers, i.e., in the epidermal, subepidermal, and mesophyll layers, as well as by distribution of pigmented cells within the tissue layer. Anthocyanins were confined to the epidermal layer or subepidermal layer in flowers with low color intensity, whereas they were also in several layers of mesophyll in more intensely colored flowers. Striped patterns on the perianth were due to the restriction of pigment to cells surrounding the vascular bundles. Color perception is influenced by the presence or absence of carotenoids, which when present, were distributed in all cell layers. Anthocyanins in combination with carotenoids resulted in a variety of flower colors ranging from red, maroon, bronze to brown, depending on the relative location of the two pigments. Four types of epidermal cell shapes were identified in Dendrobium flowers: flat, dome, elongated dome, and papillate. Epidermal cell shape and cell packing in the mesophyll affected the visual texture. Petals and sepals with flat cells and a tightly packed mesophyll had a glossy texture, whereas dome cells and loosely packed mesophyll contributed a velvety texture. The labella in the majority of flowers examined had a complex epidermis with more than one epidermal cell shape, predominantly papillate epidermal cells.
Kerry M. Strope and Mark S. Strefeler
Four heat-tolerant (`Celebration Cherry Red', `Celebration Rose', `Lasting Impressions Shadow', and `Paradise Moorea') and three non-heat-tolerant (`Lasting Impressions Twilight', `Danziger Blues', and `Pure Beauty Prepona') cultivars were identified using a Weighted Base Selection Index. These cultivars were used as parents in a full diallel crossing block with reciprocals and selfs. Progeny from five parents (25 crosses) were evaluated for heat tolerance. Four floral (fl ower number, flower diameter, flower bud number, and floral dry weight) and five vegetative characteristics (visual rating, leaf size rating, vegetative dry weight, branch number, and node number) were evaluated with emphasis placed on continued flowering under long-term heat stress. In addition, progeny from all seven parents (49 crosses) were evaluated for inheritance of adaxial leaf color, abaxial leaf color, vein color, and flower color. Significant differences were found in each data category (P < 0.001) with the exception of node number, which was not significant. Flower number varied from 0 to 2, flower diameter varied from 0 to 41 mm, floral dry weight varied from 14 to 105 mg, bud number varied from 0 to 12, branch number varied from 5 to 15, and vegetative dry weight varied from 220 to 607 mg. General and specific combining abilities of the parents were evaluated as was heritability. It was found that the four heat-tolerant cultivars had higher general combining abilities. Heat tolerance has low heritability and is controlled by many genes.
Wilfredo Seda-Martínez, Linda Wessel-Beaver, Angela Linares-Ramírez, and Jose Carlos V. Rodrigues
pistillate flowers were recorded, and fruits were harvested at maturity except for ‘Waltham’ and ‘Taína Dorada’. Number and weight of fruit per plot (per plant), average fruit weight, fruit diameter, and pulp thickness were measured. For pulp color, soluble
Robert Griesbach and Ron Beck
Differences in structural gene expression are responsible for a wide range of responses from human cancer to patterned flowers. Gene silencing is one of the ways in which gene expression is controlled. We have developed a model system to study gene silencing using a gene silencing mutation in Petunia ×hybrida (Star mutation) and the ability of certain viruses to reverse the silencing mutation. This model system was used to characterize how the Star flower color pattern was controlled.