Flower Color Mutants Research Articles

310 IN SITU GENETIC COMPLEMENTATION OF FLOWER COLOR MUTATIONS VIA PARTICLE BOMBARDMENT

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.

Genetic analysis and some properties of flower color mutants found in the progenies of X-ray irradiated Portulaca sp. "Jewel".

This paper deals with the genetic analysis of flower color in Portulaca sp. 'Jewel' using X-ray mutants. And it is also discussed on the gene for betalain biosynthesis as a marker for the change in the character. Two genes, M1 and M2 appeared to be located on the same chromosome for the expression of fiower color, with M1 being epistatic to M2. Another gene L was recognized for its hyperchromic effect on pigmentation. By means of High-performance Liquid Chromatography, biogenesis of betalain pigments was compared among the strains. Constitution of pigments in the mutants was different from that of the pigments of original strain. M2 gene was responsible for the susceptibility to changes in the temperature during the following stages. Activity of crude extracts of the enzyme was investigated among the strains. It was demonstrated that XM-3 which harbored m2 gene promotes the glycosidic degradation of betanin.

Flavonoid genetics of the 28-chromosome ?Siberian? Iris

A Chromatographic survey of flavonoids in the various flower color mutants of the 28-chromosome "Siberian" Iris (series Sibiricae subseries Sibiricae) was conducted using mutants of known genotype (Vaughn 1974). Mutants at the C locus contain the malvidin glycoside ensatin, indicating that this gene locus may control methylation of delphinidin. Clear white, a mutation at the W locus, results in the production of flavones in excess.

Modification of the B-ring during flavonoid synthesis in Petunia hybrida: Introduction of the 3?-hydroxyl group regulated by the gene Ht1

The flower-color mutants of Petunia hybrida W37 and W18, which are homozygous recessive for the anthocyanin gene An3, accumulate flavanone glycosides in the flowers. It is concluded that the gene An3 is not directly involved in the synthesis of the C15 skeleton, but that it probably takes part in modifying the skeleton. Complementation experiments with the mutants W18 and M5 show that the hydroxylating gene Ht1, which is reponsible for the introduction of the second hydroxyl group in the B-ring at position 3', is expressed after gene An3. In P. hybrida introduction of the 3'-hydroxyl group is therefore not achieved by specific incorporation of caffeic acid during synthesis of the C15 skeleton, but by hydroxylation of a C15 skeleton. When anthocyanin synthesis is blocked by homozygous recessive hydroxylating genes Ht1 and Hf1, as in the mutant M5, dihydrokaempferol-7-glucoside is accumulated. This intermediate is discussed as a possible substrate for B-ring hydroxylation.

X-ray induced mutations in Begonia x hiemalis

A study was made of the occurrence of mutants in plants of four clones of Begonia x hiemalis grown from leaf cuttings irradiated with 0, 1500, 2000 or 2500 rad of X-rays. Irradiation reduced the number and slowed down the development of adventitious shoots, but to a different degree in the four clones used. The percentage of mutated shoots was as high as 18–35% in the non-irradiated shoots. Irradiation raised it to more than 80%. In the control plants, almost exclusively flower colour mutants were found. Irradiation caused a wider range of flower colour mutants and also caused mutations of growth habit, colour and size of the leaves, and size and shape of the flower. Almost all mutants were ‘solid’, i.e. non-chimeral.

GENETICS OF LUPINUS. II. THE SELECTIVE DISADVANTAGE OF THE PINK FLOWER COLOR MUTANT IN LUPINUS NANUS.

The flower color of Lupinus nanus Dougl. is normally blue except for the white area in the center of the banner. Burlingame (19 21) reported the occurrence of pink-flowered variants which Harding and Mankinen (1967) found to be Mendelian recessives (pp). Their frequency is low, generally less than 10-3, but a few populations have been observed with as many as 1 or 2% pink-flowered plants. These frequencies are characteristic of several flower color mutants and suggest a selective disadvantage of variant flower color. The purpose of the present study is to compare relative fitness values and two fitness components, viability and reproductive fertility, of the pink and wildtype genotypes in natural populations. In order to obtain estimates of relative fitness values, outcrossing rates and genotypic frequencies are estimated.

GENETICAL STUDIES ON FLOWER COLOR MUTATIONS IN CHRYSANTHEMUM. : I. Chromatographic Analyses of Pigments in Flower Color Mutations

The pigment structure of flower color mutations in Chrysanthemum was analysed by using the paper chromatographic methods. The anthocyanin pigments in the red colored mutant line induced from Yellow Delaware was in accord with those in Delaware. Although there was no distinct difference in the flavonol pigments between Yellow Delaware and the yellow colored mutant line induced from Delaware, the latter showed the loss of one of the other yellow pigments which were present in the former.

Mutation breeding in bulbous iris

To make the sterile iris cultivar “Wedgwood” accessible to selection, bulbs were irradiated with X-rays. The aim is to induce flower colour mutations in this early flowering cultivar which is specially suitable for early forcing. The optimal dose turned out to be 1000 rad X-rays; the best moment for irradiation is immediately after lifting the bulbs in August when the growing points, which will form the new bulbs, are in the youngest possible ontogenetic stage. The size of the bulb does not seem to be an important factor. Since 1964 almost 6000 bulbs, representing approximately 25,000 growing points. have been irradiated. So far over 160 flower colour mutants, ranging from paler to darker blue with or without purple, have been obtained. Moreover, a number of other mutants — more flowers per stalk, other form of the flower or different flowering dates — have been observed. These results are discussed as well as other possible ways to reach the goal.

Somatic flower-color variations and morphological changes induced by C-14 in the snapdragon, Antirrhinum maju.

The genetic and morphological effects of radiocarbon when incorporated into plants of the common snapdragon were investigated. Plants of an F/sub 1/ hybrid heterozygous for flower color and plants of the variety Windmillers Lilac were exposed to atmosphers containing carbon dioxide enriched with C/sup 14/O/sub 2/. The estimated radiation dosages were phase specific activities of 4, 25, 150, and 900 mu c per gram carbon, respectively. The frequency of somatic mutations increased from 0.61 mutant areas per flower in controls, to phase activities of 4, 25, 150, and 900 mu c per gram carbon, respectively. The relationship between air-phase specific activity and frequency of mutant areas appeared to be linear at air-phase specific activities from 25 to 900 mu c per gram carbon; the efficiency of radiocarbon treatment was greatest at 4 mu c per gram carbon. Only two phenotypic classes of mutant areas, pink and white, were classified accurately. Neither the pink nor the white areas were attributed to mutation at specific loci. On the average, pink mutations were observed 7.5 times as frequently as white. No morphological changes in plants of the F/sub 1/ hybrid and Windmillers Lilac were observed at the three lower air-phase specific activities. Plantsmore » exposed to the 900 mu c per gram carbon air-phase activity exhibited reduced lateral branching and flower production, increases in leaf thickness, stem diameter, plant height, abnormalities in flowers, and dichotomous branching of the main stem. Comparisons with other results indicate that radiocarbon treatment was slightly more effective than equivalent amounts of ionization from chronic gamma irradiation in producing certain morphological changes. Radiocarbon and chronic gamma irradiation were not shown to differ in effect in the induction of somatic flower color mutations in snapdragons. (auth)« less