Anatomical and Biochemical Traits Associated with Field Resistance of Onion Cultivars to Onion Thrips and the Effect of Mechanical Injury on the Level of Biochemical Compounds in Onion Leaves

Thrips tabaci Lind. is a global pest and also represents a serious threat to onion production in Poland. In 2 years (2015–2016) of field studies, 8 onion cultivars were evaluated to characterize the resistance to onion thrips and to determine if any biochemical and anatomical features of onion plants are associated with antixenotic and/or antibiotic mechanisms of resistance. Additionally, the influence of mechanical injury on the content of several biochemical compounds in onion leaves was made. The resistance to thrips colonization during the migration period, abundance, and thrips damage throughout the whole vegetation season was determined. We identified two cultivars, Tęcza and Wenta, resistant to thrips colonization and abundance, and one cultivar Wenta resistant to thrips damage. A positive correlation between concentrations of the reducing sugars and thrips abundance and conversely negative relationships between the total phenolic content and thrips damage was confirmed in both years. We suspect that a thinner epidermal layer, a smaller area of epidermal and mesophilic cells, and a lower diameter of vascular bundles may favor the resistance of onion cultivars to thrips. Thrips foraging resulted in a decrease in the content of soluble sugars, sucrose, and plant pigments in the leaves of all onion varieties.

Cultivar of oil flax Y 220

The oil flax cultivar Y 220 is developed by a method of individual selection from a line k4165 at severe background after 6-field flax monocrop. It was estimated by resistance to fusariose in epicentrum of fusariose infection and to flax sickness at monocrop cultivation. Due to results of variety trials for 2019–2020, the cultivar Y 220 exceeded the standard cultivar FLIZ by yield by 0.77 t per ha. Plant height is 80–90 cm. Vegetative period is 75–80 days. Weight of 1000 seeds is equal to 6.02–6.06 g. Seeds color is brown. Oil content is 44.4%; linolenic acid content is lowered (23.3%). The cultivar Y 220 is differed with full resistance to flax sickness and high field resistance to fusarium wilt. This makes it possible to cultivate it in short crop rotations and at monocrop.

Characterization of Long Non-Coding RNAs in the Bollworm, Helicoverpa zea, and Their Possible Role in Cry1Ac-Resistance

Multiple insect pest species have developed field resistance to Bt-transgenic crops. There has been a significant amount of research on protein-coding genes that contribute to resistance, such as the up-regulation of protease activity or altered receptors. However, our understanding of the role of non-protein-coding mechanisms in Bt-resistance is minimal, as is also the case for resistance to chemical pesticides. To address this problem relative to Bt, RNA-seq was used to examine statistically significant, differential gene expression between a Cry1Ac-resistant (~100-fold resistant) and Cry1Ac-susceptible strain of Helicoverpa zea, a prevalent caterpillar pest in the USA. Significant differential expression of putative long non-coding RNAs (lncRNAs) was found in the Cry1Ac-resistant strain (58 up- and 24 down-regulated gene transcripts with an additional 10 found only in resistant and four only in susceptible caterpillars). These lncRNAs were examined as potential pseudogenes and for their genomic proximity to coding genes, both of which can be indicative of regulatory relationships between a lncRNA and coding gene expression. A possible pseudogenic lncRNA was found with similarities to a cadherin. In addition, putative lncRNAs were found significantly proximal to a serine protease, ABC transporter, and CYP coding genes, potentially involved in the mechanism of Bt and/or chemical insecticide resistance. Characterization of non-coding genetic mechanisms in Helicoverpa zea will improve the understanding of the genomic evolution of insect resistance, improve the identification of specific regulators of coding genes in general (some of which could be important in resistance), and is the first step for potentially targeting these regulators for pest control and resistance management (using molecular approaches, such as RNAi and others).

Contact Engineering Approach to Improve the Linearity of Multilevel Memristive Devices

Physical mechanisms underlying the multilevel resistive tuning over seven orders of magnitude in structures based on TiO2/Al2O3 bilayers, sandwiched between platinum electrodes, are responsible for the nonlinear dependence of the conductivity of intermediate resistance states on the writing voltage. To improve the linearity of the electric-field resistance tuning, we apply a contact engineering approach. For this purpose, platinum top electrodes were replaced with aluminum and copper ones to induce the oxygen-related electrochemical reactions at the interface with the Al2O3 switching layer of the structures. Based on experimental results, it was found that electrode material substitution provokes modification of the physical mechanism behind the resistive switching in TiO2/Al2O3 bilayers. In the case of aluminum electrodes, a memory window has been narrowed down to three orders of magnitude, while the linearity of resistance tuning was improved. For copper electrodes, a combination of effects related to metal ion diffusion with oxygen vacancies driven resistive switching was responsible for a rapid relaxation of intermediate resistance states in TiO2/Al2O3 bilayers.

Tomato hybrids with complex resistance for ground greenhouses

На фоне усиливающейся инфекционной нагрузки на культуру томата, обусловленной появлением новых болезней и новых физиологических рас традиционных патогенов, возрастает значение создания и использования в производстве гетерозисных гибридов с комплексной устойчивостью. Возрастает вредоносность новых насекомых-вредителей культуры томата. По вредоносности выходят на первое место томатная минирующая моль (Tuta absoluta) и западный цветочный трипс (Frankliniella occidentalis), который помимо нанесения прямого ущерба культуре выступает как переносчик вирусных заболеваний, в том числе вируса бронзовости (TSVW). Начатая селекционная программа на полевую устойчивость томата к трипсу позволила в 2020–2021 годах выделить восемь источников устойчивости среди образцов различных товарных групп. В результате двадцатилетней селекции созданы коммерческие гибриды с различным набором генов устойчивости. В задачи современной селекции входят этапы оценки и отбора селекционного материала на наличие генов устойчивости в генотипах методами ПЦР-диагностики, а также контроль устойчивости путем испытания материала в условиях инфекционных фонов или искусственного заражения. Важный этап – контроль товарных партий семян на присутствие генов устойчивости. Результаты ПЦР-анализа коммерческих гибридов на четыре гена устойчивости в сочетании с испытанием полевой устойчивости к кладоспориозу на сильном многолетнем инфекционном фоне приведены в табличной форме. Результаты показывают, что практически во всех товарных группах есть гибриды с устойчивостью к кладоспориозу, фузариозному увяданию, вирусу томатной мозаики (ВТоМ) и галловой нематоде. Также была обнаружена относительная устойчивость к фитофторозу у гибрида F1Изящный (Ph2\Ph2). Сегодня проводится работа по расширению числа генов для ПЦР-анализа селекционного материала. Under conditions of the increasing infectious load on the tomato crop due to the emergence of new diseases and new physiological races of traditional pathogens, the importance of creating and growing heterotic hybrids with complex resistance is increasing. The harmfulness of new insect pests of tomato culture is also increasing. In terms of harmfulness, the tomato mining moth (Tuta absoluta) and the western flower thrips (Frankliniella occidentalis) take the first place, which, in addition to causing direct damage to the culture, is a carrier of viral diseases, including Tomato spotted wilt virus. The started breeding program for the field resistance of tomato to thrips made it possible for the period 2020–2021 to identify 8 sources of resistance among the samples of various commodity groups. As a result of 20 years of selection, commercial hybrids with different sets of resistance genes have been created. The goals of modern breeding include breeding material assessment and selection for the presence of resistance genes in genotypes by PCR diagnostics method, as well as control of resistance by testing the material under infectious backgrounds or artificial infection inoculation. Another important step is the control of commercial seed lots for the presence of resistance genes. The results of PCR analysis of commercial hybrids for 4 resistance genes in combination with the test of field resistance to Cladosporium fulvum under condition of strong long-term infectious background are given in tabular form. These results show that in almost all product groups there are hybrids with resistance to ToMV, in combination with other resistances, including the relative resistance to late blight in the F1 Iziyaschniy (Ph2\Ph2) hybrid. Currently, the progress is being made towards expanding the number of genes for PCR analysis of breeding material.

Evaluation of quality indicators of potatoes of different ripeness groups in the forest-steppe of the Ob region

The results of the study of promising potato varieties in Novosibirsk region (2016-2018) are presented. The objects of the study were 14 samples of potatoes, 10 of them were modern domestic varieties not zoned in the West Siberian region. An assessment of the quality indicators of potato varieties was carried out in comparison with the following zoned varieties: Red Scarlett, Nevsky and Tuleevsky. To obtain an early harvest (75 days after planting), the varieties Lomonosovsky (36 t/ha) and Reggi (39 t/ha) were recommended for the early ripening group. In the group of mid-early varieties, the variety Samba (35 t/ha) was noted; in the mid-season group, the varieties Fritella and Vympel were distinguished (early yield 32 t/ha). High productivity during harvesting in the early ripening group was noted in the varieties Lomonosovsky (42 t/ha) and Reggi (44 t/ha). The Samba variety (44 t/ha) stood out in the mid-early ripeness group. In the mid-season ripening group, the recommended variety is Gusar (46 t/ha), which exceeded the Tuleevsky standard by 4 t/ ha. Among the varieties of the early group of ripeness, high starch content was noted in the varieties Lomonosovsky (16.3%) and Reggae (17.4%). In the mid-early and mid-season groups, one variety was distinguished in each, Samba (14.4%) and Fritella (17.0%). In the early ripening group, the dry matter content of all varieties was higher than that of the Red Scarlett standard, in the mid-early group the highest indicator was observed in the Samba variety (22.9%). In the group of mid-season varieties, the samples Vympel (25.4%) and Fritella (25.8%) exceeded the standard. High field resistance to late blight (9 points) in the epiphytotic year (2017) was revealed in the varieties Gala, Nevsky, Gusar and Fritella.

Results of testing potato hybrids in breeding nurseries in the Komi Republic

Relevance. Potato hybrids obtained when creating varieties adapted to the weather conditions of the Komi Republic must have maximum resistance to constantly changing environmental conditions while maintaining the yield indicator at a high level. In addition, breeders impose requirements for their high field resistance to the main diseases common in the region: late blight, alternaria, rhizoctonia, scab and viruses (X, Y). In 2020, in the course of a continuously operating selection process, produced on the basis of the Institute of Agrobiotechnology FRC Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences (Syktyvkar) together with the FRC potato named after A.G. Lorkh (Korenevo), samples were taken from the nursery of the main test of hybrids.Methods. The studies were carried out on five hybrids sent from the FRC of Potato named after A.G. Lorkh obtained by hybridization of the original parental forms, growing hybrid seedlings and single-root hybrids, followed by selection in nurseries of single-root hybrids, second-year hybrids, preliminary and main tests already directly at the Institute of Agrobiotechnology FRC of the Komi Scientific Center of the Ural Branch of the Russian Academy of Sciences. Observations, counts and culling in each nursery were carried out in accordance with the methodological recommendations on the technology of the potato breeding process. According to the research results, the hybrids were assessed in terms of yield, yield range (the difference between the maximum and minimum values for the study period), realization of yield potential (the ratio of the average yield to the maximum over the years of research) and coefficient of variation, as well as disease resistance.Results. As a result of a comprehensive assessment of potato samples in the nursery of the main test, three promising hybrids were identified — 1992–14, 2000–60 and 2139– 5 with an average yield at the level of standard varieties and higher (23.6–31.2t/ha), having a high stability and disease resistance.

The role of plum genotype in the inheritance of the trait of resistance to low negative temperatures

To assess the degree of inheritance in plum genotypes of the trait of resistance to the effects of damaging environmental factors of the cold season (after a thaw and after a thaw with subsequent hardening) and to identify forms with high resistance to low negative temperatures, in 2019-2020 an experiment on freezing under controlled conditions was set up (climatic chamber TH-6 (JEIO TECH, Korea)). The objects of the experiment were one-year shoots of seedlings of three hybrid families obtained as a result of controlled hybridization in 2016 (UB 8 × Smolinka, Kubanskaya Kometa × Utro, Kubanskaya Kometa × Smolinka), as well as parental varieties: Kubanskaya Kometa, Smolinka, Utro and hybrid UB 8 with various forms of field resistance to low negative temperatures (based on average long-term observations in 2007-2015) and with high indicators of agronomic valuable traits. For each component of the study of winter hardiness, the temperature regimes of freezing were selected: -22 °C for 15 hours after 5 days of thaw +3 °C (III component); -34 °C after 5 days of thaw and subsequent hardening at -5 °C within 5 days, then at -10 °C for 5 days (IV component). As a result of assessing the resistance of the hybrids to low negative temperatures, it was noted that after the thaw 73 % of the hybrids showed no damage; after a thaw followed by hardening, the total degree of freezing of hybrids varied from 0.5 points (UB 8 × Smolinka, form No. 10) to 4 points (UB 8 × Smolinka, form No. 4). Genotypes resistant to temperature changes from positive to negative with hardening from families UB 8 × Smolinka (forms No. 1, 10), Kubanskaya Kometa × Utro (form No. 3), Kubanskaya Kometa × Smolinka (form No. 2) are of interest for further breeding research. Assessment of the influence of the genome of parental forms on inheritance in hybrids of resistance to low negative temperatures according to component IV using the Spearman rank correlation method revealed an average direct insignificant correlation between winter hardiness in parental forms and hybrids.

Characterization of Prochloraz Resistance in Fusarium fujikuroi from the Heilongjiang Province in China

Prochloraz is widely used to control the rice bakanae disease caused by Fusarium fujikuroi. The current study was aimed at monitoring the development of F. fujikuroi resistance to prochloraz in the Heilongjiang province, and at analyzing the fitness of F. fujikuroi strains with different resistance levels. The results indicated that the majority of the 89 F. fujikuroi strains collected from the Heilongjiang province were resistant to prochloraz, with resistance frequency reaching 92.1%. To assess the field resistance risk of prochloraz, 21 F. fujikuroi strains with different resistance levels were selected to investigate their biological characteristics and assess their fitness. Mycelial growth, sporulation, and germination rates were significantly different among the tested strains. However, when grouped into two sub-populations, no significant difference was tested between prochloraz-resistant and prochloraz-sensitive strains. Pathogenicity assays revealed that the disease severity index of prochloraz-resistant strains was higher than that of prochloraz-sensitive strains. Cross-resistance assays showed no cross-resistance between prochloraz and five other fungicides, namely phenamacril, ipconazole, tebuconazole, carbendazim, and fluopyram. Ffcyp51A gene overexpression was observed in the prochloraz-resistant F. fujikuroi strains, following exposure to prochloraz. Collectively, these results indicated that F. fujikuroi resistance against prochloraz was severe. Furthormore, prochloraz-resistant strains were highly fit and could potentially become a dominant population in rice fields, consequently resulting in yield loss.

Complexities underlying the breeding and deployment of Dutch elm disease resistant elms

Dutch elm disease (DED) is a vascular wilt disease caused by the pathogens Ophiostoma ulmi and Ophiostoma novo-ulmi with multiple ecological phases including pathogenic (xylem), saprotrophic (bark) and vector (beetle flight and beetle feeding wound) phases. Due to the two DED pandemics during the twentieth century the use of elms in landscape and forest restoration has declined significantly. However new initiatives for elm breeding and restoration are now underway in Europe and North America. Here we discuss complexities in the DED ‘system’ that can lead to unintended consequences during elm breeding and some of the wider options for obtaining durability or ‘field resistance’ in released material, including (1) the phenotypic plasticity of disease levels in resistant cultivars infected by O. novo-ulmi; (2) shortcomings in test methods when selecting for resistance; (3) the implications of rapid evolutionary changes in current O. novo-ulmi populations for the choice of pathogen inoculum when screening; (4) the possibility of using active resistance to the pathogen in the beetle feeding wound, and low attractiveness of elm cultivars to feeding beetles, in addition to resistance in the xylem; (5) the risk that genes from susceptible and exotic elms be introgressed into resistant cultivars; (6) risks posed by unintentional changes in the host microbiome; and (7) the biosecurity risks posed by resistant elm deployment. In addition, attention needs to be paid to the disease pressures within which resistant elms will be released. In the future, biotechnology may further enhance our understanding of the various resistance processes in elms and our potential to deploy trees with highly durable resistance in elm restoration. Hopefully the different elm resistance processes will prove to be largely under durable, additive, multigenic control. Elm breeding programmes cannot afford to get into the host–pathogen arms races that characterise some agricultural host–pathogen systems.