Fusarium wilt pathogens represent an ongoing threat to pepper production worldwide. This is the first report providing data on the molecular identification of Fusarium fungi that cause wilt in pepper in the southern regions of Russia. Monitoring of the Fusarium infection on pepper was carried out in 2019–2022 in two economically important regions of this culture production: the Krasnodar Krai and Crimea. Based on a phylogenetic analysis of the translation elongation factor (EF1a) and the internal transcribed spacer (ITS), as well as the macro- and micromorphological characteristics of the fungi, the causative agents of Fusarium wilt have been identified. The causative agents identified as representatives of the Fusarium species composition included: F. clavus, F. solani, F. oxysporum, F. verticillioides, F. commune, F. torulosum, and F. sporotrichioides. Depending on the region, the specifics of biodiversity and the ratio of these species in pathocomplexes were noted. In Crimea, wilting could be attributed to all of the identified species; in the Krasnodar Krai, F. verticillioides and F. clavus were found to contribute to wilting. The pathogenicity test showed that the pathogens of pepper wilting in Russia, in addition to the already known F. oxysporum and F. solani, are the species F. clavus and F. verticillioides. This is the first report on the ability of these species to cause Fusarium wilt in pepper cultures. The obtained data will be of practical value for the development of biological control measures for fungi of the genus Fusarium, which cause pepper wilt in areas of industrial production and seed production. In addition, data on species composition and aggressive isolates will be used in a pepper breeding program for resistance to Fusarium wilt.

Fusarium basal rot of onions causes large losses during storage of commercial production of onion bulbs, which in turn adversely affects the food market situation in the off-season period. There are no data on the composition of Fusarium spp., which causes onion basal rot in the Russian Federation. Therefore, our research was aimed at Fusarium spp. causing onion basal rot in the Moscow Region of the Russian Federation and studying the pathogenicity of these species for the host plant. We studied 20 isolates of Fusarium spp. collected from affected mature bulbs and seed bulbs. Species identification of the isolates was carried out using analysis of the nucleotide sequences of the three genetic loci ITS, tef1 and rpb2, as well as was based on the macro- and micromorphological characteristics of these isolates. As a result, the species F. annulatum (F. fujikuroi species complex), F. oxysporum (F. oxysporum species complex), F. acuminatum (F. tricinctum species complex) and F. solani (F. solani species complex) were identified to involve in the pathogenesis of Fusarium basal rot. We have shown for the first time that the species F. annulatum and F. acuminatum are highly aggressive and capable of causing onion basal rot. The predominant species were F. annulatum and F. oxysporum. The proportion of these species in the total number of analyzed isolates was 60% and 25%, respectively. The largest proportion (33%) of highly aggressive on mature bulbs isolates was found in the species F. annulatum. The data obtained provide practical insights for developing strategies to manage Fusarium fungi responsible for onion basal rot Moscow Region of the Russian Federation. In addition, data about species composition and aggressive isolates may be used in onion breeding for resistance to Fusarium basal rot.

Современное состояние рынка овощных корнеплодов в РФ и пути решения проблемы продовольственной безопасности

Relevance.An important feature that determines the technological qualities of varieties and hybrids of beetroot is an erect, compact leaf rosette that persists until the end of the vegetation of plants. In this regard, much attention is paid to the selection of resistance to diseases affecting the leaves of plants, including Cercospora beticola Sacc. When creating resistant to Cercospora interline hybrids based on CMS, the selection of parent components plays an important role. In agroclimatic conditions of the Moscow region, Cercospora on industrial beetroot rarely reaches an economically significant threshold of harmfulness. However, in 2019, epiphytic development of Cercospora on summer first-year crops was observed in the block film greenhouse of the «Federal Scientific Vegetable Center», which allowed to assess the promising breeding material.Material and method. Phytomonitoring on beetroot plantings and sowing of the experimental production Department of the «Federal Scientific Vegetable Center» growing was carried out by methods of visual diagnostics and microscopy. Cercospora lesion in the breeding nursery was evaluated on an 11-point scale, the ranking of samples into five groups of resistance - according to the degree of disease development (R%). Analyzed: 28 sterile lines (А); 13 fertile lines of fixers (В); 25 lines of pollinators (С) and 38 hybrid F1 (АхВхС).Results. It was found that more than half of the studied lines were receptive to Cercospora. The share of relatively resistant lines was 13%. Most of them (8%) are ms - lines « obtained by pollination of CMS with mf-lines В. A close relationship (r=0.86-0.89) between the index of lesion of fixators and the degree of disease development of ms- lines was revealed, in some simple combinations a positive effect of heterosis on resistance to Cercospora relative to mf-В was noted. In the submitted sample F1 hybrids mainly observed between the nature of inheritance according to the degree of disease development (R, %), mixed effects the base line stability of pollinator mf-С (r=0,32) and a closer correlation of the stability of hybrid offspring the F1 with the resistant parent ms-line А (r=0.55). As a result of the evaluation, the most resistant to Cercospora ms- and mf-lines and derived from them hybrid F1, among which only 9% were included in the group of relatively resistant to C. beticola.

НОВЫЙ СОРТИМЕНТ ДЛЯ СЕЛЕКЦИИ ОВОЩНЫХ КОРНЕПЛОДОВ И ТЕХНОЛОГИИ ЕГО ПОДДЕРЖАНИЯ

Considering its capacities, the generative system of Beta vulgaris L. is regarded as highly productive. While inbreeding, the reproductive potential of cross-pollinated beet plants with gametophytic self-incompatibility (SI) changes significantly and is determined by a joint effect of multiple factors including the level of inbred depression. In the present study, original data have been obtained revealing relationships between inbred beet seed productivity, its self-incompatibility and microgametophyte parameters, which is crucial for developing and maintaining constant fertile beet lines. It has been discovered that inbred depression increases the number of sterile microgametes and anomalous pollen grains, reduces pollen fertility and the length of pollen tubes. As a result, the seed yield in inbred beet progeny, including SI ones, reduces significantly just after the third inbreeding. At the same time, highly productive inbred beet is characterized by a lower rate of pollen tube growth in vitro. In inbred plants, there is no close relationship between pollen viability and seed productivity, because the elimination of germinated male gametes and degeneration of seed embryos may go over the entire period of fertilization starting its progamic phase. The SI plants have more degenerating embryos than self-fertile ones, but seed vessel outgrowth in the seeds with abortive embryos makes them morphologically similar to fertile seeds. For that reason, when assessing inbred beet plants based on their self-incompatibility/self-fertility, one should consider the qualitative characteristics of the seeds. Using the method of recurrent selection based on such factors as seed productivity, pollen tube length and field germination rate increase the output of plant forms with a potentially high self-compatibility in their progeny. To support such genotypes in the progeny, one has to, starting from the third inbreeding, perform sib crossing to reduce the negative effect of inbred depression and self-incompatibility.