Velvet flower (Salpiglossis sinuata, Solanaceae) can be used as an excellent demonstration plant for horticultural crop breeding classes. Salpiglossis produces large trumpetlike flowers exhibiting an assortment of corolla colors and pigmentation patterns. The pistil is large (3 to 4 cm or 1.2 to 1.6 inches long) with a sticky stigmatal tip and flowers can be easily emasculated prior to anthesis. The large pollen grains are shed in tetrads which can be separated and placed on the stigmatal surface. It takes eight to nine weeks from seeding to blooming, with a prolific flowering cycle that comes in flushes. Numerous seeds (about 750 per capsule) are obtained in three weeks after self- or cross-pollination. The influences of three genes that control flower color and pigmentation pattern can be conveniently demonstrated with their dominant and recessive alleles. The R gene controls flower color with red (RR or Rr) being dominant over yellow (rr). The D gene controls the density of pigmentation with solid (DD or Dd) color being dominant over dilute (dd) color. Corolla color striping is controlled by the St gene with striped (stst) being recessive to nonstriped (StSt or Stst) pattern. By using diploid lines of genotypes RRDD (red, solid), RRdd (red, dilute), or rrdd (yellow, dilute) and their crosses, students can easily observe a dominant phenotypic expression in the F1 hybrid and the digenic 9:3:3:1 segregation ratio in the F2 progeny. Another gene (C) that controls flower opening can also be used to show its influence on cleistogamous (closed, selfpollinated, CC or Cc) versus normal chasmogamous (open-pollinated, cc) corolla development. In addition, the induction and use of polyploid (4x) plants in plant breeding can also be demonstrated using this species.
Mark J. Bassett
The effects of gri on seed coat and flower color were investigated in a study using Lamprecht line V0400 (PI 527735) as the known source of gri. Seed and flower color data were taken on observations of F2, BC1-F2, and BC2,-F2 populations from crosses of V0400 with the recurrent parent S-593. Segregation was observed for a unique flower color pattern: wing petals have a very pale tinge of blue (laelia), and the banner petal has two violet dots (≈3- to 4-mm diameter) on a nearly white background. This very pale laelia flower color cosegregates with gray-white seed coats produced by gri. Furthermore, the very pale laelia color depends on the action of V for expression and is extinguished by v, which produces pure white flowers. Thus, it was demonstrated that the very pale laelia flower color, for which Lamprecht tentatively proposed the gene symbol vpal, is not controlled by an allele at V but is a pleiotropic effect of gri. It was also demonstrated that Lamprecht line V0060 (PI 527717) carries vlae, not v, as indicated by the genotypic notes accompanying the Lamprecht seed collection.
Young-Seok Kwon and Fenny Dane
Watermelon (Citrullus lanatus Thumb. Matsum. and Nakai) flower petals usually are yellow, but in watermelon line Kw-695, light-green flowers were detected. To study the inheritance of light-green flower color, Kw-695 plants were crossed with yellow-flowered Korean cultures `SS-4' and `Dalgona'. The resulting F1, F2, and reciprocal backcross generations were analyzed for flower color. Segregation ratios in the F2 and backcross to Kw-695 were 3 yellow: 1 light green and 1 yellow: 1 light green, respectively. Backcross generations to the yellow-flowered parents showed yellow flowers only. These results indicate that inheritance of the light-green flower character in Kw-695 is governed by a single recessive gene. We propose the gf gene symbol for the green flower trait. Kw-695 plants have large vines with large, light-green leaves. The plants are andromonoecious, have large, oval, bright yellow-green fruit with irregular dark-green stripes, bright yellow-orange, inedible flesh with very low sugar content (about 3.2 °Brix), and light-yellow seeds. The trait should be useful as a marker in watermelon breeding programs. Linkages between this trait and other genetic markers in watermelon will be investigated.
Andrea Quintana, Jana Albrechtova, Tom Davis, Robert J. Griesbach, and Rosanna Freyre
Wild Anagallis monelli has blue or orange flowers. Hybrids with red flowers were developed at the Univ. of New Hampshire. Orange is due to pelargonidin, but delphinidin and malvidin can also be present; red is due to delphinidin and malvidin; and blue is due to malvidin only. In this study, blue and orange wild diploid accessions were used to develop four F2 populations (n = 46 to 81). In three populations, segregation ratios supported a previously proposed three-gene model for flower color in this species (P> 0.01). In the fourth population, white flower color was obtained in addition to blue, orange, and red. Molecular studies of genes in the anthocyanin pathway using a candidate gene approach are in progress. In a separate F2 population, blue, violet, lilac, and red flower colors were obtained. One hybrid per color was studied on three replicate plants. Cells with vacuoles containing anthocyanins in upper and lower petal epidermis peels were counted in five flowers per clone using light microscopy (M = 200×). Blue and red hybrids had mostly blue and red cells, respectively, on both surfaces. Lilac and violet hybrids included cells that were blue and intermediate (containing both red and blue) on both surfaces, and also had red cells on the lower epidermis only. Violet hybrids had more blue cells on the upper epidermis than the lilac hybrids. Anthocyanins were determined by HPLC for each petal epidermis in the four flower colors. The blue hybrid had only malvidin in both upper and lower epidermis, and the red hybrid had mainly delphinidin in both surfaces. Lilac and violet hybrids had small amounts (2% and 2.5%, respectively) of delphinidin on upper surfaces, while lower surfaces had 25% to 33% delphinidin.
Wesley E. Kloos, Carol G. George, and Laurie K. Sorge
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.
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.
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
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.