Genetics and Molecular Biology

Plant breeding is a complex and fundamental science for the development of modern agriculture. It is based on genetic analyses and follows the patterns of heredity and variability of plant organisms. Modern breeding methods cover the classical or conventional genetic approaches, such as inbreeding (homozygous lines), heterosis effect, polyploidy, haploidy and others, and are complemented by molecular genetic analyses and genetic engineering approaches. For this reason, it can be asserted that modern science, with its ever-evolving methods in biotechnology and genetic engineering, offers opportunities to create new varieties and lines of crops, adapted to modern conditions and requirements.

The essence of plant selection is the selection of better types of plants among the existing options, in terms of yield and quality of the products used as food, easy cultivation, harvesting and processing, tolerance to environmental stressors and resistance to pests. Each of these aspects of agronomic importance or food can be considered as part of a multitude of specific traits, each with its own range of variation. Manipulating one attribute without considering the rest is relatively dangerous as it can lead to the production of unwanted forms without economic value.

The selection process is accompanied by complex studies of plant physiology and biochemistry, phytopathology, agrochemistry, etc. All of them are aimed at identifying and evaluating new plant phenotypes, their genotypic analysis, as well as subsequent projections of potentially valuable economic qualities, such as productivity, abiotic and biotic stress factors, creating new forms with specific characteristics for the purposes of certain breeding programs and more.

The establishment of a breeding program is primarily subject to the objectives set for the particular crop, in accordance with its features, and hence the guidelines of the breeding work. First of all, a basic knowledge of the crop, subject of selection, its biological features, taxonomy, origin, environmental requirements, state of play, at the moment of research in the field of breeding of this crop and trends of selection programs is required. This information is the basis of a future prospective program for achieving specific breeding tasks.

Creating new varieties and lines as part of the breeding work is a long and costly process, but the end goal justifies the effort. As a rule, classical breeding uses the natural diversity of representatives of different plant species as a source of valuable economic qualities and the creation of new varieties based on their purposeful combination as a result of interspecies and interspecies crossings. In many cases, in breeding practice, wild relatives of the same species (if any) or even of other genera (distant hybridization) are used as the source of new genes, whereby genes carrying new traits are incorporated into the genome of the cultural parent.

The selection process can be divided into the following steps:

• Availability of source genetic material as a basis for selection work
• Study of the source material
• Use of appropriate breeding methods combined with targeted selection to obtain new plant forms – an analysis of F1, F2 and subsequent generations obtained by self-pollination or cross-pollination. Selection.
• Selection and assessment. Assessment and complex analysis of the obtained perspective plants. Selection.
• Testing of newly created lines and varieties

Types of selection methods:

1. Combination selection:

A: Crossing (hybridization):

– interspecific crossing;

– intraspecific crossing;

– crossbred hybridization

B: Selection:

– mass

– individual

2. Heterosis – a manifestation of quality in the hybrid generation that goes beyond the parent line; manifested in F1 and used in the so-called heterosis selection mainly in maize, tomatoes, tobacco – hybrid crossing.
3. Mutagenesis.

– natural

– induced by physical and chemical mutagenic factors

4. Polyploidy, aneuploidy, and haploidy – treatment with colchicine.
5. Tissue culture and genetic engineering in breeding:

• micropropagation
• embryo and crop cultures
• somaclonal variation
• somatic hybridization
• isolation and transfer of genes
• fusion of protoplasts
• transgenic plants (recombinants of DNA technology)

6. Marker selection – Marker Assisted Selection (MAS).
7. Genomic selection.

Groups of varieties by cannabinoid content:

1. High THC content, minimum CBD
2. 50:50 THC: CBD and different THC: CBD ratios
3. High CBD content, minimum THC

The laboratory currently works with the following varieties:

1. Kompolti
2. Cannabis sativa sp.
3. Moby Dick
4. Grandma Soul
5. RC hybrid
6. White cheddar

Research is currently being carried out on industrial hemp varieties with a high CBD and THC content of less than 0.2%.

The results obtained with the Kompolti variety show that the concentrations of CBD in the plants are higher than the standard for the variety, not only in field and greenhouse plants, but also in plants grown in vitro, including through calli cultures. Plant biotechnology (cell and tissue culture) methods are generally applied to control and accelerate the production of hybrid lines with improved characteristics.

Preliminary data from the experiments show promising results regarding the increase in the concentration of the main cannabinoids – THC and CBD. Positive results were also obtained for other cannabinoids in the cannabinoid profile.