Relevance One of the basic directions of the cabbage crop breeding is the creation of F1 hybrids with a complex of economically valuable traits. This process is difficult and time-consuming as to get pure lines must be within 6-12 years hold inbreeding. Herewith not every line gives the desired heterotic effect that also requires additional verification. Methods Biotechnological method culture of isolated microspores in vitro, which allows in the first generation to receive a line with 100% homozygosity, was used to speed up the breeding process. Combination ability were performed in complete diallel cross on the basic morphological signs. Results Culture medium for cultivation of isolated microspores in vitro was optimized for each genotype of cabbage for the best embryoids regeneration. Maximum amount of embryoids was received on medium with pH 6.2 using ampicillin 100 mg/l and zeatin 1 mg/l: 466.7 ± 153.2 PCs/100 buds. A new source material for breeding – doubled haploid lines of cabbage was received. Lines – the best parents for F1 hybrids with high yield, compact rosette of leaves, with optimum inside and short outside cabbage stump was created. Studies have shown that optimization of breeding process in case of creation of pure lines of cabbage in 3 years with microspore culture requires to reduce the breeding process in 2 times.

The method  of development  of functionally sterile forms of tomato from hybrids derived from crossing between functionally sterile and fertile lines is described. The characteristic  of two new lines on the main morphological; biological and economically useful traits and combining ability for yield and fruit weight are shown.

Relevance. The selection for productivity and stability on different stages in the breeding process includes an assessment of the adaptive capacity and genotypes ecological stability. Therefore breeding for the resistance to abiotic environmental factors is closely connected with the adaptive breeding, which has received special attention in recent years.Methodology. The work was carried out at the “A.L. Mazlumov All-Russian Research Institute of Sugar Beet and Sugar” in 2011-2020. Male-sterile forms of sugar beet were crossed with fertile diploid multi-seeded pollinators (ARRISBS selections) by topcross method. The resulting hybrids were assessed for yield, sugar content and sugar collection according by standard methods used at the “A.L. Mazlumov ARRISBS”. It is carried out the annual work, including selection of the best and rejection of the worst options for the studied characteristics. An assessment was made of lines and hybrid combinations of sugar beet for the resistance to a complex of unfavorable natural and climatic factors based on the characteristics of yield, sugar content and seed productivity.Results. The results of improving selections over ten years show an increase in the weight of the root crop and the sugar content for the original single-seeded and multi-seeded materials. Single-seeded (MS-2113, MS-Perla) and multi-seeded (OP-15465, OP-15676, OP-15202) lines with high combining ability in terms of yield and sugar content of root crops were identified. An increase in the resulting parameter - sugar collection - was noted by 2020 (to 8,8-9,0 t/ha), illustrating the positive dynamics of the breeding process of sugar beet for plants of the first life year. An increase in the weight of 1000 seeds (to 13,4-13,9 g) and separate fruiting (to 98-99%) was shown during the breeding process for plants of the second life year.Conclusion. The studied hybrid combinations have a wide reaction rate to a complex of natural climatic factors: elevated temperatures in combination with high and low humidity.

A model of late maturing F1 hybrid of white head cabbage for long-term storing and suitable for national recipe “golubci” have been developed based on requirements for varieties and F1 hybrids grown in the South in the conditions of drought, high temperatures and low air humidity. Combining ability of seven self-incompatible inbred lines of white head cabbage was studied by the system of full diallel crosses in conditions of Pridnestrovian Moldavian Republic. These lines were developed on the base of heat tolerant varieties ‘Biruchekutskaya’, ‘Volna’, ‘Lada’, ‘Moldavanka’ and ‘Kharkovskaya Zimnyaya’ bred in the south. Out of 42 hybrid combinations studied 15 significantly surpassed in productivity the variety ‘Zavadovskaya’ that is traditionally grown by local farmers for pickling and recipe “golubci”. High GCA effects for productivity showed the following breeding lines: Bu1, Ml3 and Kl5. Polygenes, controlling the high yield ability, mainly were dominant and single-directed, however the correlation betweenyield ability and GCA effect was middle, r=0.63±0.35. No correlation was observed inbreeding line between GCA effect and truly heterosis effect in hybrid combinations (r=0.19). Disease resistance analysis revealed lines Bu1 and Kl5 that had shown resistance to Fusarium yellows. Two hybrid combination Kl5xBu1 and Ml3xBu1 were highly tolerant to thrips attacks according to analysis of all promising hybrid combinations, carried out in natural infection background. Weak correlation was observed between the number of damaged leaves in cabbage head and dry matter content, r=0.41±0.21, and also there is no correlation revealed with sugar contents, ascorbic acid and nitrate content. High tolerance of hybrids with participation of line Bu1 explained the partial dominance nature of the trait. Hybrid combinations Kl5xBu1 and Ml3xBu1 called ‘Batal’ and ‘Shedevr’, respectively, included in registry of Moldova and PMR.