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A b s t r a c tPeculiarity of chemical composition of Brassica rapa L. crops (high water content and low content of fats) determine their low-calorie character. They are notable for relatively high content of carbohydrates and proteins, including all essential amino acids. Biochemical composition varies greatly among B. rapa members. We are the first to carry out a multifactor evaluation of valuable morphological and biochemical traits of B. rapa accessions from the core collection of Vavilov Institute of Plant Genetic Resources (VIR, 96 samples) in eco-geographical study (South China and Leningrad region of Russia) under field trials and under a greenhouse conditions. By means of the developed SSR (simple sequence repeats) markers which are in linked disequilibrium with QTL of morphological and biochemical traits, the molecular genetic analysis was firstly carried out in leafy, rooted, and oilseed B. rapa genotypes from the VIR core collection. As a result, new genetic sources for quality parameters have been found among the samples investigated. In average, the samples did not differ noticeably on plant morphology (leaf length, leaf width, petiole size, hairiness, colour) in field tests when growing in South China and in Leningrad region, whereas in a greenhouse at higher plant density the leaf size decreased, e.g. in Chinese cabbage, pak-choi, wutacai, and turnip the leaves were 5-12 cm longer and wider in the field tests. Under field trials, we revealed the significant and high significant correlations between dry matter (DM) and ascorbic acid (AA) level (r = 0.51, p < 0.05), DM and chlorophyll a (Chla) content (r = 0.59, p < 0.05), DM and carotenoids (Cd) (r = 0.55, p < 0.05), DM and carotins (Cn) (r = 0.67, p < 0.05), DM and -carotene (-C) (r = 0.59, p < 0.05), DM and protein (P) level (r = 0.49, p < 0.05); Chla and Chlb (r = 0.93, p < 0.001), Chla and Cd (r = 0.59, p < 0.05), Chla and Cn (r = 0.49, p < 0.05), Chla and -C (r = 0.99, p < 0.001); Chlb and -C (r = 0.92, p < 0.001); Cd and Cn (r = 0.49, p < 0.05), Cd and -C (r = 0.63, p < 0.05); Cn and -C (r = 0.49, p < 0.05). In the greenhouse, the significant and high significant r values were as follows: r = 0.59 (p < 0.05) for DM and AA, r = 0.58 (p < 0.05) for DM and Chlb, r = 0.53 (p < 0.05) for DM and Cd, r = 0.71 (p < 0.001) for DM and Cn; r = 0.59 (p < 0.05) for AA and Chlb, r = 0.83 (p < 0.001) for AA and Cd, r = 0.58 (p < 0.05) for AA and P; r = 0.74 (p < 0.001) for Chla and Chlb, r = 0.67 (p < 0.05) for Chla and Cn, r = 0.95 (p < 0.001) Chla and -C; r = 0.48 (p < 0.05) for Chlb and Cd, r = 0.87 (p < 0.001) for Chlb and Cn, r = 0.64 (p < 0.05) for Chlb and -C; r = 0.63 (p < 0.05) for Cn and -C. The semi-headed Chinese cabbage Syaobaikou and Dunganskaya, pak-choi Mayskaya, and especially Ching Pang Yu Tsain with a distinctly high level of chlorophylls and carotene, are indicated as new promising genetic sources for valuable biochemical parameters under both field and greenhouse conditions. Their indices in the field trials and greenhous...

Cruciferous plants belonging to the genus Brassica of the Cabbage family (Brassicaceae) are cultivated as vegetables, oilseeds and forage crops; they occupy one of the first places in Russia in the gross yield of vegetables. The yield of cabbage crops is adversely affected by various pathogens, including bacterial, viral and fungal infections. The diseases such as black rot of cabbage (caused by the bacterium Xanthomonas campestris pv. campestris), downy mildew (caused by Hyaloperonospora parasitica), Turnip Mosaic Virus (TuMV) are not included in the list of quarantine diseases in the territory of the Russian Federation and Eurasian Economic Union (EAEU), but they can affect a part of the sown area and lead to significant (up to 100 %) crop losses. The development of cultivars resistant to these pathogens is an important trend in Brassica crop breeding in addition to existing methods of agrotechnical and chemical protection. The development of molecular marker techniques and marker-assisted selection (MAS) methods makes it possible to significantly increase the efficiency of breeding resistant cabbage cultivars. The review contains information on the currently known genes and quantitative trait loci (QTLs) associated with resistance to black rot, downy mildew, and TuMV. Molecular mapping data for resistance genes of Brassica species are shown. The molecular markers (RFLP, AFLP, SSR, EST, SNP, InDel, SLAF and others) closely linked to the resistance loci and SCAR-, STS-and dCAPS-markers derived from them for molecular screening are listed. The use of the markers reviewed to assess the Brassica accessions and lines can help the researchers in finding sources and donors of pathogen resistance of cabbage crops.

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Based on comparison of R2R3 Myb genes in Solanaceae (S. lycopersicum: Ant1, Ant2, S. melongena: Myb1, C. annuum: Myb113-like1 and Myb113-like2) and Brassicaceae crops, a search for orthologous sequences was The sequences encoding Myb114 TF in Brassica oleracea and Brassica rapa was found to be the closest in a nucleotide structure to the previously investigated genes in Solanaceae. Тhе polymorphism in the promoter region of the Capsicum annuum Myb113-like1 gene that regulates anthocyanin biosynthesis: an additional 148 bp repeat and 2(1) bp insertion in the forms with impaired anthocyanin synthesis in fruits was studied. A relationship between the presence of an insert in the promoter (Myb113-like1pr+148) and polymorphisms in the exon regions of Myb113-like1delTand Myb113-like2C/Аgenes associated with impaired anthocyanin synthesis was established. A number of polymorphisms of the Myb114 gene in vegetable crops of the cabbage family (Brassica oleracea, Brassica rapa), which closely correlate with high/low accumulation of anthocyanins in leaves, were identified. In B. oleracea, SNPs that lead to the replacement of two amino acids located in the region of DNAbinding domains were found, which leads to a change in the efficiency of binding of this transcription factor and the promoters of structural biosynthesis genes. A protein sequence encoded by the Myb114 gene in accessions of the leafy turnip (B. rapa) with a high accumulation of anthocyanins in the leaves differed from the accessions without anthocyanin accumulation in the leaves by five amino acids, while the regions of DNA-binding domains were the same in the forms with various anthocyanin accumulation.