The Genetics of Some Ornamental Plants, with Special Reference to Anthocyanin Variegation. (continued from p. 114.)

Abstract

With reference to the genetics of Impatiens Balsamina L., Mirabilis jalapa L., and Celosia cristata L., the author described some experimental results in his previous papers (Kanna 1926, 1927, 1929, 1933, 1934). The investigations with special reference to the anthocyanin variegation have been furthered the main results obtained being as follows:
1. With the experimental data for balsam as basis, are described the behavior of three genes for the flower type, ten genes for the flower color, and three for other characters.
2. The white blotches on the petals of balsam are transmitted in inheritance as a recessive character, although its segregating aspect is not simple.
3. Albinism in balsam is segregated as a Mendelian recessive to normal green.
4. The appearance of deficient seedlings is due to gene mutation from dominant to recessive.
5. Two types of fasciation are observed, hereditary and non-hereditary.
6. The haploid chromosome number of balsam is seven.
7. Two linkage groups are established in balsam, including six genes. The s linkage group contains three genes, s, w and d, the p linkage group includes three genes, s, sp, and e, while most of the other genes are independent of one another in their segregations.
8. The pink flower of Celosia is an allelomorph of magenta and yellow, being recessive to the former and dominant to the latter.
9. Genes T, t', t. which are responsible for the stem length in Celosia, constitute a set of triple allelomorphs.
10. Eight mutable genes for the anthocyanin variegation, three in balsam, three in Mirabilis and two in Celasia, were detected.
11. The striped flower of these three plants frequently give rise to monochromatic flowers as owing to mutation from recessive to dominant in their progeny.
12. As the result of mutation from dominant to recessive, the striped strains also throw out some individuals bearing ground-colored flowers that breed true to type.
13. Three genes, self-colored, variegated, and ground-clored, constitute aset of multiple allelomorphs, the genes being constant except the second.
14. Four types of menochromatic bud-variation are observed on the striped balsam. As to the position of the mutated histogens, the plant characteristics are as follows:
15. The striped strain of Celosia frequently bears three kinds of bud-variation, pure magenta (Type A), a mosaic of yellow and magenta in each petal (Type B), and pure magenta (Type C).
16. In Mirabilis, three types of monochromatic bud-variation are observed and their chimerical nature discussed.
17. The intensity of the ground color of the striped strains of balsam changes at times owing to the presence of mutable gene e.
18. The degree of variegation is affected by a modifier v-r in balsam and by m in Mirabilis, resulting in two types of fine and coarse variegations. The two types are transmitted by monohybrid inheritance.
19. Occasionally, owing to mutability of v-r and m bud-variation from coarse to fine variegation are observed in balsam and Mirabilis.
20. The various combinations of eight genes in Mirabilis result in different flower colors with or without variegation.
21. The tricolored Mirabilis, yellow and magenta stripes on white background, carries two mutable genes, rⁱ and cⁱ.
22. Linkage occurs between genes cⁱ and m in Mirabilis.
23. The direction of mutation in allelomorphs is discussed.
24. Mutation generally occurs late in the plant ontogeny.
25. Finally the mutable genes are considered generally in connection with their direction, frequency, position, time of change, the ground color of the striped flowers, and also other contributing factors.