Self Flower-Color Inheritance and Mutation in Mirabilis Jalapa L

Abstract

Mirabilis jalapa, commonly known as ((Four O'clock"' "Sweet Marvel of Peru," or '(Printoponite," belongs to the Nyctaginaceae. This species is cultivated for the brilliant color and pleasing odor of its flowers. Due to its simplicity, the breeding behavior of the self flower colors has furnished classical material for illustrating the simple laws of inheritance. It may be shown, however, that the breeding behavior of these self flower colors is not so simple as was first implied, and that where formerly there were only a few flower-color classes recognized, now there are many. CORRENS (1902,1904), the first to investigate this species genetically, failed in many cases to recognize and classify the flower colors correctly. His attention was chiefly directed toward an interpretation of the "yellow X white" varietal cross in which reds (red being used in a very general sense to cover a number of different shades) were obtained in the F1 and F,, but he failed to distinguish between the F, red flower-color types. The careful distinction between the color classes came with the work of MARRYAT (1909). Aided by the discovery of "recessive white" (MARRYAT'S W7), she was able to detect the genotypes of all the material used in her investigations. The "rose pink" homozygote and "light pink" heterozygote of KIERNAN and WHITE (1926) were probably the first true pinks known to genetic literature on this species. The pink so frequently referred to in text-book illustrations as resulting from a "red X white" four o'clock cross is probably not pink, but magenta (see also MARRYAT 1909, andKIERNAN andWHITE 1926).M . jalapa was introduced into Europe by the Spaniards in 1596. I t is native to Peru, as one of its common names, "Sweet Marvel of Peru," suggests. HEIMERL (1901) found it to be native also to northern Mexico and the southern boundary of the United States. Under cultivation color varieties not known to the wild condition have occurred, and are recurring, spontaneously. MATERIALS AND METHODSThis investigation (1) reviews all crosses, and reciprocals, previously made with true-breeding self flower-color varieties of M . jalapa;(2) attempts to describe the breeding behavior of Flesh Pink and Light Rosaline Purple, two new true-breeding types which have been found during the

Mendel’s controlled pollination experiments in Mirabilis jalapa confirmed his discovery of the gamete theory of inheritance in Pisum

“…All colored flower lines of M. jalapa were concluded to have derived from the crimson strain, the material basis of which was a mixture of magenta anthocyanin and a soluble yellow pigment [ 26 ]. The flower color in M. jalapa was considered as being controlled by two independent non-allelic loci with a certain kind of interaction: Y and y control the basic color yellow, and R , Rp , rp , and r are multiple alleles that modify Y and y to different degrees of red [ 27 ]. The genotypes of the crimson inbred lines may be YYrr or YYRpRp , those of the yellow inbred lines may be YYrr or YYrprp , and those of the dominant white varieties may be yyRR (recessive white yyrr was discovered in the twentieth century, and is therefore not considered here).…”

“…The genotypes of the crimson inbred lines may be YYrr or YYRpRp , those of the yellow inbred lines may be YYrr or YYrprp , and those of the dominant white varieties may be yyRR (recessive white yyrr was discovered in the twentieth century, and is therefore not considered here). It is known that RP , Rp , and rp in series of multiple R alleles show epistatic interaction in such a way that the white recessive character of y is covered up, leading to the segregation ratio of offspring deviating from 3:1 in general [ 24 , 27 ]. Also, the F 1 hybrid of Showalter’s crimson × yellow was stable orange red YYRr , while the F 1 hybrid of the crimson × white was stable rhodamine purple YyRR [ 27 ].…”

“…It is known that RP , Rp , and rp in series of multiple R alleles show epistatic interaction in such a way that the white recessive character of y is covered up, leading to the segregation ratio of offspring deviating from 3:1 in general [ 24 , 27 ]. Also, the F 1 hybrid of Showalter’s crimson × yellow was stable orange red YYRr , while the F 1 hybrid of the crimson × white was stable rhodamine purple YyRR [ 27 ]. Therefore, according to Mendel’s experience and the introduction above, it can be concluded that the genotypes of the materials used by Mendel might have been crimson YYRR , yellow YYrr , and white yyRR , respectively (Fig.…”

“…3 Putative pedigrees of Crimson × Yellow in Mirabilis jalapa . a , pedigree adopted from Showalter [ 27 ], the gray square indicates the imprecise relationship between pollens and eggs in bulked pollination before Mendel’s M. jalapa work; b . assumed pedigree of the single pollen experiment completed by Mendel; the rectangle marks Mendel’s precise operation between one pollen grain and one ovule in M. jalapa …”