An in-depth glucosinolate (GLS) profiling was performed on a core collection of 91 Brassica rapa accessions, representing diverse morphotypes of heterogeneous geographical origin, to better understand the natural variation in GLS accumulation and GLS breakdown product formation. Leaves of the 91 B. rapa accessions were analyzed for their GLS composition by UHPLC-DAD and the corresponding breakdown products by GC-MS. Fifteen different GLSs were identified, and aliphatic GLSs prevailed regarding diversity and concentration. Twenty-three GLS breakdown products were identified, among them nine isothiocyanates, ten nitriles, and four epithionitriles. Epithionitriles were the prevailing breakdown products due to the high abundance of alkenyl GLSs. The large scale data set allowed the identification of correlations in abundance of specific GLSs or of GLS breakdown products. Discriminant function analysis identified subspecies with high levels of similarity in the acquired metabolite profiles. In general, the five main subspecies grouped significantly in terms of their GLS profiles.

A Brassica rapa collection of 239 accessions, based on two core collections representing different morphotypes from different geographical origins, is presented and its use for association mapping is illustrated for flowering time. We analyzed phenotypic variation of leaf and seed pod traits, plant architecture, and flowering time using data collected from three field experiments and evaluated the genetic diversity with a set of SSR markers. The Wageningen University and Research Centre (WUR) and the Vavilov Research Institute of Plant Industry (VIR) core collections had similar representations of most morphotypes, as illustrated by the phenotypic and genetic variation within these groups. The analysis of population structure revealed five subgroups in the collection, whereas previous studies of the WUR core collection indicated four subgroups; the fifth group identified consisted mainly of oil accessions from the VIR core collection, winter oils from Pakistan, and a number of other types. A very small group of summer oils is described, that is not related to other oil accessions. A candidate gene approach was chosen for association mapping of flowering time with a BrFLC1 biallelic CAPS marker and a BrFLC2 multiallelic SSR marker. The two markers were significantly associated with flowering time, but their effects were confined to certain morphotypes and (or) alleles. Based on these results, we discuss the optimal design for an association mapping population and the need to fix the heterogeneous accessions to facilitate phenotyping and genotyping.

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Turnip is a biennial crop and, consequently, the creation of pure lines for breeding is a time-consuming process. The production of pure turnip lines using doubled haploids produced in isolated microspore culture has not been sufficiently developed. The aim of the present work was to determine some key factors inducing embryogenesis in the isolated microspore culture of turnip, as well as investigating the manners of embryo development. It was shown that the acidity of the medium is an important factor in embryo production; different optimal pH levels ranging from 6.2 to 6.6 corresponded to individual genotypes. Such factors as the cold treatment of buds and the addition of activated charcoal to the nutrient medium increased the responsiveness of all genotypes studied. The turnip variety ‘Ronde witte roodkop herfst’ demonstrated a genetic disorder in the development of microspores; namely, non-separation of some microspores from tetrads. In the in vitro culture, each of the daughter microspores developed on its own. This indicates the dependence of the possibility of embryogenesis in the turnip microspore culture on the genotype. Results suggest that the initiation of secondary embryogenesis in primary embryos leads to an increase in the proportion of doubled haploid plants.

Tomato (Lycopersicon esculentum Mill.) is an economically important and widely cultivated vegetable crop that is consumed both fresh and processed. The nutritional value of tomato fruits is related to the content of carotenoids, polyphenols, sugars, organic acids, minerals and vitamins. Currently, there is a growing interest in the qualitative and quantitative increase in the content of health-promoting compounds in tomato fruits. VIR Lycopersicon (Tourn.) Mill. genetic resources collection includes 7678 accessions of one cultivated and nine wild species, which in turn provides ample opportunities for searching for information on the variability of the content of biologically active substances and searching for sources with a high content of them in the gene pool. Our work presents the results of the study of 70 accessions of cultivated and wild tomato on the main biochemical characteristics: the content of dry matter, ascorbic acid, sugars, carotenoids, chlorophylls and anthocyanins. As the basis for the selection of accessions for the study, accessions with various colors of fruits, including new accessions with varying content of anthocyanin, were taken. As a result of this study, the amplitude of variability in the content of dry matter (3.72–8.88 and 9.62–11.33 %), sugars (1.50–5.65 and 2.20–2.70 %), ascorbic acid (12.40–35.56 and 23.62– 28.14 mg/100 g), titratable acidity (0.14–0.46 and 0.33–0.48 %), chlorophylls (0.14–5.11 and 2.95–4.57 mg/100 g), carotenoids (0.97–99.86 and 1.03–10.06 mg/100 g) and anthocyanins (3.00–588.86 and 84.31–152.71 mg/100 g) in the fruits of cultivated and wild tomatoes, respectively, was determined. We have determined correlations between the content of dry matter and monosaccharides (r = 0.40, p ≤ 0.05), total sugars (r = 0.37, p ≤ 0.05) and ascorbic acid (r = 0.32, p ≤ 0.05); the content of ascorbic acid and carotenoids (r = 0.25, p ≤ 0.05). A high dependence of the content of chlorophyll a and b among themselves (r = 0.89, p ≤ 0.05), as well as between the content of chlorophyll b and anthocyanins (r = 0.47, p ≤ 0.05), the content of β-carotene (r = 0.26, p ≤ 0.05) and the content of monosaccharides (r = –0.29, p ≤ 0.05) has been noted. We have identif ied tomato accessions with a high content of individual chemical substances, as well as with a complex of traits that can be used as sources in breeding for a high content of dry matter, sugars, ascorbic acid, pigments and anthocyanins.

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...