The cultivated gerbera daisy [Gerbera hybrida (G. jamesonii Bolus ex Adlam × G. viridifolia Schultz-Bip)] produces flowers that have either a dark (shades of dark brown, brown-black, black-purple, or black) or light (shades of green-yellow, yellow-green, or light yellow) central disk. The dark-centered varieties have increased in popularity over the past 20 years and provided an exciting color contrast, especially in white, yellow, and various pastel-colored flowers. The objective of this investigation was to determine the mode of inheritance of disk color in gerberas. A series of crosses were made to produce PA, PB, F1, F2, BC1A, and BC1B progeny to complete the Mendelian genetic analysis. Phenotypic segregation ratios indicated that dark disk color was determined by a single dominant gene, designated Dc, and the light disk color by a recessive gene, dc. Dominance appeared to be complete in that the disk color was similar in both homozygous and heterozygous Dc plants.
Wesley E. Kloos, Carol G. George, and Laurie K. Sorge
The biosynthetic pathway for anthocyanins has been studied using genetic, biochemical and molecular biological tools. In the past decade, the core pathway genes have been cloned; a number of genes which act to modify anthocyanin structure have been cloned more recently. The first results in color modification have been reduced flower color intensity using gene suppression methods. In particular, we have utilized chalcone synthase (CHS) and dihydroflavonol reductase (DFR) genes and sense suppression in our experimental system, Petunia hybrida, and in the commercial crops, chrysan-themum (Dendranthema morifolium) and rose (Rosa hybrida). In petunia a range of new phenotypes was obtained; genetic stability of suppressed pheno-types will be described. In chrysanthemum a white-flowering derivative of a pink-flowering variety will be described. In rose uniform, partial reduction in pigment intensity throughout the flower was observed in over a dozen trans-genie derivatives of a red-flowering variety.
Mark J. Bassett
The inheritance of flower and seedcoat color was studied using Lamprecht line M0137 (PI 527845) of common bean (Phaseolus vulgaris L.) as the source of a new allele, V wf, at the V locus. The cross M0137 c res V wf × C v BC2 5-593 (a genetic tester stock) was studied in progeny of the F1, F2, F3, and F4 generations. The observed segregation for flower and seed colors was consistent with the hypothesis that M0137 carried a new allele, V wf, that produced (in the presence of P C J G B) white flowers and black seeds rather than the white flowers and mineral-brown seeds produced (in the presence of P C J G B) by v. The V/V wf genotype produced cobalt-violet flowers, the same as V/v. A test cross of F3 V wf × t BC1 5-593 bipunctata demonstrated that V wf is not allelic with t, a gene that can produce white or colored flowers and self-colored or partly colored seeds, depending on background genotype.
Harvey J. Lang, Nancy Howard Agnew, and Bridget K. Behe
Determining consumer preferences for specific plant attributes and plant use can assist in the development of breeding program objectives and marketing strategies. Consumers in Ames, Iowa participated in an intercept-survey to determine their knowledge of, use of, and preference for several varieties of New Guinea Impatiens (Impatiens × hawkeri). Of the population surveyed, 44% had never seen New Guinea Impatiens. Of those that had previously purchased New Guineas, 40% purchased their plants from a retail greenhouse. Outdoor container plantings were the preferred use of New Guinea Impatiens. Mother's Day was chosen by 88% of the respondents as the most appropriate holiday for a gift purchase. Considering plant characteristics, consumers rated condition of the plant as the most important attribute, followed by flower color, flower number, and price. Consumers were asked to rate plants on display comprised of three factors: flower color, leaf variegation, and price. MANOVA was used to determine the most important factor and the trade-off consumers made when expressing a preference for one plant over another.
R. J. Griesbach
Genetic complementation was used to correct the albescent flower color mutation of the orchid Doritis pulcherrima. The Zea mays anthocyanin regulatory genes C 1 and B were introduced into the petal cells via particle bombardment. Anthocyanin pigmentation developed within the bombarded cells after 48 hours. This suggests that the albescent phenotype was the result of a defective regulatory gene(s) and not the result of a defective structural gene(s). Genetic complementation via particle bombardment requires considerably less time than via classical breeding and could be used on other species or with other genes.
Valentina Schmitzer, Robert Veberic, Gregor Osterc, and Franci Stampar
for parks as well as home gardens. A vast selection of different cultivars of Rosa × hybrida with a color spectrum ranging from whites to intense purples is available. Especially in red rose cultivars, a visible change in color during flower
H.M. Ariyarathne and D.P. Coyne
Halo blight is one of the most important bacterial diseases of common beans (Phaseolus vulgaris L.). It is serious under moderate temperature and high humidity conditions. The disease is caused by a seed-borne bacterium, Pseudomonas syringae pv. phaseolicola (Burkh.) Dowson (Psp). The inheritance of leaf reactions to Psp, flower, and stem color was studied using greenhouse-grown 109 F9 recombinant inbred lines (RI) from the P. vulgaris cross BelNeb 1 [resistant (R)] (USDA/NE) × A 55 [susceptible (S)] (CIAT). Two Psp strains, HB16 (NE) and 83-Sc2A (NE), were inoculated using the water-soaking method. A segregation ratio of 1 R:1 S RI lines were observed for disease reactions in leaves for both strains indicating major gene control. The presence of recombinants for SR, RS to the strains indicated that different genes were involved. Stem (SC) and flower (FC) color traits were each determined by two major genes. Linkages were found for reactions to the two Psp strains and also between FC and SC. No linkages were observed from FC and also SC with reactions to Psp strains.
An in vivo system was developed to determine the effects of pH on naturally occurring pigment complexes within cells. The in vivo system was based on a transposable element activator (Ac) inserted into the Ph6 gene. The transposable element activator (Ac) was crossed into two genetically marked Petunia hybrida lines expressing known flavonoid pigments. Plants expressing the transposable element activator (Ac) produced variegated flowers in which the background tissue was lighter in intensity than the sectors. Depending on the genetic background in which the transposable element is expressed, progeny with darker sectors that were also redder in color than the background tissue could also be obtained. The anthocyanin and copigment composition was the same for both of the differently colored sectors and background tissue, while the pH was lower by 0.4 unit in the redder sectors. It was suggested that the Ph6 gene might be a regulatory gene that controls the expression of the pH and anthocyanin concentration.
Bridget Behe, Robert Nelson, Susan Barton, Charles Hall, Steve Turner, and Charles Safley
Consumers in five U.S. markets evaluated photographs of geranium plants with regard to purchase likelihood. Photographic images were colored electronically to produce uniform geranium plants with five flower colors (pink, white, red, lavender, and blue) and three leaf variegation patterns (dark zone, white zone, and no zonal pattern). Photographs were mounted on cards with five selected price points ranging from ($1.39 to $2.79). We randomly generated an orthogonal array, partial-factorial design for consumers to rate a reduced number of choices. Consumers shopping in cooperating garden centers located in Dallas, Texas; Montgomery, Ala.; Athens, Ga.; Charlotte, N.C.; and Wilmington, Dela., rated 25 photographs on the basis of their likelihood to purchase the plants shown. Conjoint analysis revealed that customers in the Georgia garden center placed the highest proportion of their decision to buy on leaf variegation (29%), while customers in the Alabama outlet placed the most emphasis on price (46% of the decision). Shoppers in Texas valued flower color most highly (58% of their decision to buy). Demographic characteristics and past purchase behavior also varied widely, suggesting diverse marketing strategies for geraniums.
Yanjie Wang, Yeqing Chen, Man Yuan, Zeyun Xue, Qijiang Jin, and Yingchun Xu
( Zhang, 2011 ). These cultivars possess several attractive flower colors including red, pink, white, yellow, and versicolor, but compared with other ornamental plants, the lotus flower color is not rich in diversity yet. Flower color has been regarded as