Natural rubber (NR) remains an indispensable raw material with unique properties that is used in the manufacture of a large number of products and the global demand for it is growing every year. The only industrially important source of NR is the tropical tree Hevea brasiliensis (Willd. ex A.Juss.) Müll.Arg., thus alternative sources of rubber are required. For the temperate zone, the most suitable source of high quality rubber is the Russian (Kazakh) dandelion Taraxacum kok-saghyz L.E. Rodin (TKS). An obstacle to the widespread industrial cultivation of TKS is its high heterozygosity, poor growth energy, and low competitiveness in the field, as well as inbreeding depression. Rapid cultivation of TKS requires the use of modern technologies of marker-assisted and genomic selection, as well as approaches of genetic engineering and genome editing. This review is devoted to describing the progress in the field of molecular genetics, genomics, and genetic engineering of TKS. Sequencing and annotation of the entire TKS genome made it possible to identify a large number of SNPs, which were subsequently used in genotyping. To date, a total of 90 functional genes have been identified that control the rubber synthesis pathway in TKS. The most important of these proteins are part of the rubber transferase complex and are encoded by eight genes for cis-prenyltransferases (TkCPT), two genes for cis-prenyltransferase-like proteins (TkCPTL), one gene for rubber elongation factor (TkREF), and nine genes for small rubber particle proteins (TkSRPP). In TKS, genes for enzymes of inulin metabolism have also been identified and genome-wide studies of other gene families are also underway. Comparative transcriptomic and proteomic studies of TKS lines with different accumulations of NR are also being carried out, which help to identify genes and proteins involved in the synthesis, regulation, and accumulation of this natural polymer. A number of authors already use the knowledge gained in the genetic engineering of TKS and the main goal of these works is the rapid transformation of the TKS into an economically viable rubber crop. There are no great successes in this area so far, therefore work on genetic transformation and genome editing of TKS should be continued, considering the recent results of genome-wide studies.

Dandelion kok-saghyz (Taraxacum kok-saghyz Rodin) is a producer of high quality natural rubber. To grow this type of dandelion in the ground is associated with many difficulties, some of which can be solved using hydroponic, bioponic and aeroponic cultivation methods. In this research, experiments were performed on the cultivation of kok-saghyz in hydroponics, bioponics and aeroponics, in which there were used the balanced mineral and organic fertilizers in liquid form. The optimal growth of dandelions indoors was observed under the illumination of phyto lamps with red-blue-neutral spectra. In the hydroponic method of cultivation, the roots of kok-saghyz formed decay after prolonged growth, while in bioponics and aeroponics, the roots turned out to be massive and the plants developed fully. Under aeroponic cultivation, the average weight of a three-month-old kok-saghyz plant was 27±1.2 grams, the roots by wet weight were 10±0.3 grams, the dry weight was 2.35±0.08 grams and the rubber content was 0.8±0.04% per wet weight of the root, respectively. During the aeroponic cultivation of koksaghyz, by spraying the root system with a nutrient solution the roots developed well without decay. It is shown that these methods can be used in the cultivation of kok-saghyz year-round in a greenhouse and indoors, while the plants were able to produce rubber.

Grafting with resistant rootstocks is one of the most effective methods to prevent soil-borne diseases, and it can influence vegetative growth, flowering, maturation periods, and fruit quality, thereby ensuring high yields. In this study, four species from the family Cucurbitaceae were tested as potential candidates for grafting cucumber and melon: Cucurbita ficifolia Bouché, Cucurbita moschata L., Cucurbita pepo L. and Cucurbita maxima Duch. The study focused on the grafting methods that optimize growth parameters and the accumulation of hormones and vitamins in rootstock. The results indicated that Cucurbita maxima Duch. is the most suitable rootstock material for grafting to Cucumis sativus L. and Cucumis melo L., as it exhibited superior plant and root mass. Among the two grafting methods tested, the tongue approach (‘X’) demonstrated the best results in terms of growth parameters and the accumulation of indole-3-acetic acid (IAA) and vitamins in the scion leaves. IAA and vitamin concentrations were measured using HPLC in grafted samples at 2, 4 and 6 weeks of age. In the ‘X’ method, IAA accumulation from the end of the second week was twice as high compared to control plants. This method also showed higher vitamin content, with increased levels of B vitamins and vitamin C at the end of the 4th week (25.2–135.1 and 52.3–67.0 %, respectively), and vitamins A, E, D₃, K starting from the 2nd week (1.5–2 times higher). Conversely, the insertion or slant cut grafting method (‘Y’) did not show any significant increase in the analyzed parameters and was comparable to the control. The ‘X’ method for grafting both Cucumis sativus L. and Cucumis melo L. onto Cucurbita maxima Duch. plants demonstrated the best results and is recommended for production.

Finding a suitable rootstock for Cucumis sativus L. is an important area of research, as it is aimed at extending the fruiting period and increasing the yield. In such studies, it is important to evaluate various biochemical parameters in addition to morphometric data, such as amino acid and auxin content, which will reflect the effectiveness of the rootstock for scion growth. In this research, we tested 56 genotypes and lines from four species of the Cucurbitaceae family as potential candidates for grafting cucumber rootstock: Cucurbita ficifolia Bouché, Cucurbita moschata L., Cucurbita pepo L. and Cucurbita maxima Duch. The study focused on the study of morphometric parameters, amino acid and indoleacetic acid (IAA) accumulation in rootstocks at the age of 2 and 4 weeks. Based on the results of the work, the Dunganskaya otb 3 variety of C. maxima was selected as a rootstock for cucumber, since it showed the largest plant and root weight, as well as the highest content of amino acids and IAA. Further, an optimized tongue grafting method was used for grafting cucumber with the selected variety of C. maxima, which in turn contributed to the rapid healing and adaptation of the scion. Also, a significant increase in the amino acids L-valine, L-threonine, L-alanine, L-tyrosine by 28.8; 38.8; 42.5; 98%, respectively and IAA by 39% in the scions compared to the control cucumber plants were observed at the end of the fourth week after grafting. The yield of grafted cucumber plants per plant and per square meter showed an increase of 23% compared to the control. In conclusion, from the obtained data, it can be assumed that grafting of C. sativus onto C. maxima plants is the most suitable and can be recommended for production.