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Inheritance of some traits in honesty (Lunaria L.)
Section 3. Biology
Boika Olena,
PhD-student, Zaporizhzhya National University, Ukraine, assistant of the chair of landscape design and plant genetics
E-mail: genetika@znu.edu.ua
Lyakh Viktor, Doctor of biological science, professor, chief of the chair of landscape design and plant genetics
Inheritance of some traits in honesty (Lunaria L.)
Abstract: Inheritance character of the some morphological and physiological traits such as white color of corolla, chlorophyll mutation of “albina” type and plant development type was investigated in honesty. Hybr-idological analysis demonstrated that white corolla color was inherited as monogenic and recessive trait, showing a characteristic 3:1 phenotypical ratio in the second generation of hybrids. It was established that the chlorophyll mutation of “albina” type, which was revealed in the progeny of interspecific hybrids of honesty in Lunaria redi-viva x Lunaria annua cross combination, was controlled by one recessive gene. A simple genetic control of plant development type with the dominance of perennial type and reciprocal effects were found in crossings of Lunaria annua and Lunaria rediviva.
Keywords: Lunaria, inheritance, flower color, chlorophyll mutation of “albina” type, plant development type.
1. Introduction
Honesty (Lunaria L.) is a cruciferous crop that is used in many different fields of human activity. It is an ornamental garden plant with lilac, pink, red and white flowers. Light-green, green and dark green color of leaves create a very good-looking plants. Due to ecological requirements it can grow in shade and semi-shade. Honesty produces characteristic silver, translucent seed silicula that gave common name of this plant in England — money plant (penny plant) [1].
But this crop is not only ornamental, but oilseeds plant too. Its oil is also known as a lubricant. Lunaria’s oil has valuable fatty acid content. It includes important and rare acids, such as nervonic and erucic. Nervonic acid is mono-unsaturated Omega-9 fatty acid. It was found in sphingolipids of white matter human brain. It is also known that this acid takes part in biosynthesis of nerve cell myelin, constituent of membrane phospholipids [2]. The content of this acid in honesty may reach 20-25 % [3].
Honesty plants can be used as a source of 3-ketoacylCoA synthase (KSC) gene as well. This gene increases the content of nervonic acid in transformed yeast and transgenic plants [4].
Lunaria genus includes two species. Lunaria annua L. is an annual plant which blooms at the beginning of summer. In some publications this species is named as Lunaria biennis with biennial type of development. Lunaria rediviva L. is a perennial plant. It is more common in gardens than annual species. Flowering of this species starts in April in the middle of spring and lasts near the month [5].
Now the genetics of this crop remains poorly understood. The inheritance nature of different characters in honesty is not almost investigated and nothing is known about interspecific hybrids as well.
Due to some studies the number of chromosomes is equal for two species of honesty [6; 7]. This information has allowed us to begin the work on obtaining interspecific hybrids, which were first established in Zaporizhzhya National University [8].
The aim of our investigations was to establish the inheritance pattern of some morphological and physiological traits. For this, the crossings between annual and perennial species in reciprocal combinations, as well as between annual samples with different flower color were carried out and the hybrids of the first and second generations were analyzed.
2. Materials and methods
As a material the plants of Lunaria annua L. and Lu-naria rediviva L. species, F1 and F2 hybrids between them in reciprocal cross combinations were used. Hybridization between initial species was made in artificial conditions. Parental species, Fx and F2 hybrid populations were grown both field and in indoor controlled conditions (18/6 hours day/night, 25 °C, 60-70 % of humidity). F2 hybrids were obtained by self-pollination of F1 hybrids. The F2 seeds were individually harvested from each F1 hybrid plant and sown separately.
X 2 — criteria was used to satisfy the pattern of model segregation [9].
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Section 3. Biology
3. Results and Discussion
3.1. Inheritance of flower color in honesty
White color of corolla is well known among the plants. This trait is revealed in many species of Brassicaceae family and is controlled by the different ways. White flower colour was observed in B. carinata [10]. F1 progeny after crossing lines with yellow and white flowers showed intermediate (cream-colour) expression while in F2 a 1:2:1 ratio was found, confirming monogenic inheritance with incomplete
Table 1. - Ratio of flower
dominance. Snogerup et al. [11] in interspecific crossing experiments with Brassica cretica found that some F1 plants were white-petalled indicating dominance of white color over yellow color. In Brassica juncea Anand and Mishra [12] indicated the dominance of yellow petal colour over white petal colour. Brar et al. [13] in crosses between yellow-petalled and white-petalled samples of Brassica juncea indicated the dominance of yellow over white color in F1 and 12:3:1 segregation ratio in F2 proving the control of this trait by two epistatic genes. color in Lunaria L. genus
Sample Corolla color Ratio X2
lilac (L) white (W)
Lunaria annua + - - -
- + - -
F1L. annua (L) x L. annua (W) + - - -
F1L. annua (W) x L. annua (L) + - - -
F2 L. annua (L) x L. annua (W) 19 8 3:1 0.15
F2 L. annua (W) x L. annua (L) 21 7 3:1 0.15
Flower color is an important systematic trait. Flower of plants in Lunaria L. genus has four sepals and four petals. Sepals may be of light green, green and red-green, lilac-green color. In perennial Lunaria rediviva the flower color varies
from light-lilac to dark lilac, sometimes with red shade. In annual Lunaria annua the same colors as in the perennial one are characteristic and however white color of corolla is well known (fig. 1).
Fig. 1. Different colors
To know about the inheritance of white color of corolla several crossings between annual plants with different colors (white and lilac) were made. Hybrid seeds were sown and the plants were analyzed during the flowering. In F1 generation all plants had lilac corolla of flower. In second generation the number of plants with colored and non-colored corolla was counted. These data are presented in Table 1. How we can see from the table 1, the phenotypic ratio is equal to 3:1 and indicates that the trait of white flower color is inherited as monogenic and recessive trait.
3.2. Inheritance of “albina” chlorophyll mutation
The chlorophyll deficiency of “albina” type was found in Brassica rapa after seed treatment with ethylene imine [14].
It was derived during study of the inheritance of the chlorotic cotyledon trait. The recessive homozygotes were “albina” plants while the heterozygotes were chlorotic cotyledon plants. Similar chlorophyll deficiency is widely known in other crops, for instance, in sunflower [15]. It is lethal and is maintained throw heterozygotes.
of corolla in L. annua
In our experiments on interspecific hybridization in L. rediviva x L. annua cross-combination in second generation the mutation of chlorophyll deficiency of “albina” type was appeared at the seedling stage. This chlorophyll mutation is characterized by white cotyledons and it was always lethal (fig. 2). The segregation data in F2 generation are presented in the table 2. Hybridological analysis showed that this mutation is controlled by one recessive gene (3:1 ratio).
Fig. 2. Normal and with “albina” chlorophyll deficiency F2 seedlings of honesty
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Inheritance of some traits in honesty (Lunaria L.)
Table 2. - Segregation ratio of normal and mutant plants in F2 generation of L. rediviva x L. annua interspecific hybrid
Normal green plants Plants with “albina” chlorophyll deficiency Ratio x 2
51 16 3:1 0.19
3.3. Inheritance of plant development type in Lunaria genus
The data on inheritance of development type in Brassi-caceae family are very limited. It was mostly investigated the time of flowering and maturity. Campbell and Kondra [16] found dominance for early flowering and early maturity analyzing parental, F1, and F2 populations of oilseed rape. It was established that the time of flowering was polygeni-cally controlled in Raphanus genus, however F1 interspecific hybrids between plants from wild populations of Raphanus raphanistrum and Raphanus sativus were almost intermediate between the parents [17]. In contrast, McIntyre and Best [18] showed the dominance of the late-flowering allele over early-flowering one in Thlaspi arvense because all of the F1 plants had the late-flowering phenotype and the F2 generation gave 3:1 segregation ratio of late-flowering to early-flowering phenotypes.
Two species of Lunaria genus have the differences in plant development type. One of them is perennial, another — annual. At Zaporyzhyzhya National University the reciprocal interspecific hybrids between these species were produced. Two generations of hybrid plants were analyzed (results are shown in table 3). All F1 plants were perennials in both cross-combinations. After self-pollination the seeds were harvested and sown separately from each hybrid plant. F2 hybrid populations in both combinations were studied (table 3).
In F2 L. rediviva x L. annua cross-combination annual and perennial plants were found. The plants with annual development type flowered in the year of the sowing at the beginning of the summer (June), they formed the pods and died after that. Plants with perennial type of development in the first sowing year give only leaves and never produce flowers. They
are winter-green plants and have a rosette of leaves under the snow. Next spring these plants give new leaves, flowers and produce pods. Perennials save their leaves to the next year and bloomed every spring.
In F2 L. annua x L. rediviva cross-combination besides annual and typically perennial plants, the plants with unusual plant development type (we called this type as intermediate) were revealed. Our unusual plants have other path of development. They bloom at the first year, however at the end of vegetation in late summer (August), produce a pods, but not die and save the rosette of leaves to the next year. After winter in the middle of spring (April) these plants bloom the second time, give the pods and after that die. So, they give seeds two times during life cycle. It is interesting to note that in reciprocal L. rediviva x L. annua combination the plants with “intermediate” type of development were not found.
As we can see from the table 3, in F2 L. rediviva x L. annua combination the ratio of perennials to annuals was approximately equal to 3:1. However, the number of perennial plants was bigger than it must be theoretically (113 instead of 98). In reciprocal (L. annua x L. rediviva) combination, there were three groups of plants. If we combine intermediates with annuals because of blooming in the first year, the ratio of perennials to annuals will be equal to 2.07:1 instead of 3:1. When we summarize intermediates with perennials, because these plants save the leaf rosette and hang out the winter, the ratio of perennials to annuals is transformed to 4.09:1. But, in any way the observed segregation is in accordance with theoretical 3:1 segregation and not contradicts the theory of monogenetic control of this trait. The differences in reciprocal segregations give an opportunity to suggest the existing the mother cytoplasm influence, on the trait of plant development type in honesty.
Table 3. - Ratio of plants with different development type in interspecific hybrids of honesty
Sample Perennial type Annual type Ratio X 2
Lunaria annua - - + - -
Lunaria rediviva + - - - -
Fx generation L. rediviva x L. annua + - - - -
F2 generation L. rediviva x L. annua 113 (97.5) 0 17 (32.5) 3:1 9.85 (10.83)
Fx generation L. annua x L. rediviva + - - - -
F2 generation L. annua x L. rediviva 110 (122.25) 21 (0) 32 (40.75) 3:1 1- 2.64 2- 5.6 (10.83)
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Section 3. Biology
4. Conclusions
1. The trait of white flower color is inherited as monogenic and recessive trait.
2. “Albina” chlorophyll mutation is controlled by one recessive gene (3:1 ratio).
3. The observed segregation on the trait of plant development type in honesty is in accordance with theoretical 3:1 segregation and not contradicts the theory of monogenetic control of this trait. The differences in reciprocal segregations give an opportunity to suggest the existing the mother cytoplasm influence.
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