н а у ч н о п р а к т и ч е с к и й ж у р н а л [ 18 ] о в о щ и р о с с и и № 3 (3 2) 2 0 1 6 СЕЛЕКЦИЯ И СЕМЕНОВОДСТВО СЕЛЬСКОХОЗЯЙСТВЕННЫХ РАСТЕНИЙ

Cucurbita crops are among the most valuable and widely cultivated vegetable crops in global agriculture. Cucurbit seed oil meets the requirements of functional nutrition; it is material for the food industry and medicines based on natural ingredients. The present research was aimed at studying features of the biochemical composition of oil in seeds of the main cultivated Cucurbita L. species from the collection of the N.I. Vavilov Institute (VIR) grown in the conditions of the Astrakhan Experiment Station (AES) of VIR. The oil content in seeds of Cucurbita L. species varied from 40 to 49.7%. Over 80% of the fatty acids (FA) composition (FAC) was represented by oleic (13.6–49.6) and linoleic (33.5–69.3%) acids. The accessions of Cucurbita mixta Pang. were noted for high values of saturated FAs (palmitic and stearic), those of Cucurbita pepo var. melopepo (L.) Harz. of linoleic and linolenic, and those of Cucurbita pepo L. of oleic acid. The multiple factor analysis showed significant differences in FAC in accessions of C. pepo var. melopepo, Cucurbita maxima Duch. and C. pepo. The performed study allowed us to reveal FAC features in seeds of each Cucurbita species from the VIR collection and to identify the accessions with the best economically important indicators.

Background. Modern production imposes increased requirements to the range of used cultivars, so the development of new cultivars and hybrids most adapted to certain soil and climatic conditions is an important task of breeding. Materials and methods. Table beet accessions from the VIR collection originating from 17 countries were chosen as the material for the present research. The accessions were studied at Pushkin and Pavlovsk Laboratories of VIR, at the Genetic Diversity and Plant Bioresources Center of the All-Russian Breeding and Technological Institute of Horticulture and Nursery (VSTISP) and at Maikop Experiment Station, a branch of VIR, according to VIR's guidelines. Results. The relationships between earliness, bolting resistance, cold tolerance and resistance to black root have been established. The majority of the studied accessions had medium resistance to black root. The cultivars 'Asmer Detroit 72' (k-3113, Great Britain), 'Bravo' (k-3047, Russia) and 'Podzimnyaya A-474' (k-1678, Russia) distinguished by resistance to black root, were also characterized by cold tolerance and stable productivity. The differences in bolting resistance among the accessions were found to depend on their origin. The cultivars from Sweden, Finland and from the Russian Northwest were most resistant to bolting. The early accessions 'Perfected Detroit Dark Red' (k-1815, Canada), 'Bikor' (k-2873, the Netherlands), 'Severny shar' (k-1586, Russia) and 'Polyarnaya ploskaya' (k-1585, Russia) were characterized by high rates of the vegetative mass growth and bolting resistance. It was noted that the absolutely monogermic varieties have lower ripening rates, productivity, and resistance to bolting, compared to the multigerm ones, but have similar chemical composition indicators and root quality. Accessions with a wide distribution area that maintain high root productivity at 115-120% to the reference in different climatic conditions have been identified. Conclusions. The research has resulted in the identification of table beet accessions characterized by a complex of biological and economically important traits. The relationships between earliness, resistance to bolting and cold tolerance have been revealed. Genetic sources of monogermicity, bolting resistance, cold tolerance, black root resistance and high root quality are recommended for the use in breeding.

Background. Currently, the most widespread and harmful disease of cucumber is downy mildew. In this regard, a vitally important trend in cucumber breeding is the development of new cultivars, more resistant to downy mildew, for cultivation in different regions. Solution to this problem requires searching for donors of resistance for use in breeding practice.Materials and methods. The studies were conducted at Volgograd Experiment Station of VIR using conventional methods. The material for the screening was the collection of cucumber genetic resources held by VIR.Results and conclusions. During 32 years of work, 2873 cucumber accessions from VIR’s holdings were screened. As a result, 57 accessions with resistance or relative resistance to downy mildew were identified, i. e. 2.0% of the total number studied. Immune accessions were not found. Among the selected accessions, those with the highest yield are noteworthy: landraces from Azerbaijan (temp. k-3999 and temp. k-4004) as well as the cultivars from China ‘Zungsungerum-oi’ (temp. k-3701), ‘Tianin mini cucumber’ (k-4490), ‘Tian Uzin Yao No. 5’ (temp. k-3840) and ‘Tian Uzin Yang No. 6’ (temp. k-3841). Of the resistant and relatively resistant accessions, 76% were from Southeast Asia. During the years of study, 23 accessions, previously resistant to downy mildew, lost their resistance and suffered severe damage from the disease. Hence, it seems obvious that resistant accessions should be periodically retested for susceptibility to downy mildew. Twenty accessions were selected to form a group of tolerant ones. Of these, ‘Yeo leam sam chuk oi’ (k-4545), ‘Crispy Top F1’ (temp. k-3549) and ‘Pchelka F1’ (temp. k-3981) had the highest average yield.

The article marked the stages of formation and studying of the VIR's collection of vegetable and melon crops. The structure of the collection and its significance for breeding is shown. The most important genetic resources of economically important traits are given.