Studying self-fertility in new black currant cultivars from the VIR collection in Northwestern Russia

Background. An important task is to search for and select highly self-fertile cultivars for plant breeding programs and for setting single-cultivar plantings in commercial horticulture.Materials and methods. Cultivars were assessed for their self-fertility levels at Pushkin and Pavlovsk Laboratories of VIR in 2019–2022. Thirty black currant cultivars of eight genetic groups served as the research material. Their levels of self-fertility were tested using conventional techniques. Free pollination served as the control. The resulting data were analyzed according to the main indicators crucial for precise characterization of a cultivar’s self-fertility level: fruit setting rate, berry weight, seed yield, and fertilization effectiveness. The data were statistically processed using Microsoft Excel and the guidelines by B. A. Dospekhov. Fruit setting rate, berry weight, seed yield and fertilization effectiveness were considered for each pollination variant.Results and conclusion. Cultivars with high and stable self-fertility levels were identified as potential valuable sources for breeding programs: ‘Partizanka Bryanskaya’ (k-45548), ‘Ben Gairn’(k-45524), ‘Litvinovskaya’ (k-45542), ‘Mushketer’ (k-45544), ‘Raduzhnaya’ (k-45549), ‘Ben Lomond’ (k-32611), and ‘Vertikal’ (k-45528). Cvs. ‘Partizanka Bryanskaya’ (k-45548), ‘Ben Gairn’ (k-45524), ‘Mushketer’ (k-45544), and ‘Vertikal’ (k-45528) may be used in single-cultivar plantings because they are able to set the same number of berries under natural self-pollination and free pollination. Natural self-pollination (autogamy) led to a decrease in the size of berries and the number of seeds in them. An increase in the main self-fertility indicators was observed under artificial self-pollination and free pollination

EVALUATION OF SELF-FERTILITY IN BLACK CURRANT CULTIVARS IN THE NORTHWEST OF RUSSIA

Background. High yield is one of the main requirements for modern black currant cultivars. It depends on many factors, but is always linked to self-fertility. Highly selffertile cultivars are of particular importance in areas with unfavorable weather conditions during flowering, because they are able to provide high yields even in single-cultivar plantings. In this regard, it is very important to study selffertility of cultivars in order to identify those with the highest level of this character for use in breeding and large-scale cultivation.Materials and methods. The study of selffertility was carried out at Pushkin and Pavlovsk Laboratories of VIR in 2014–2017. Fifty-seven black currant cultivars of different genetic and ecogeographic origin were the material of the research. The degree of self-fertility was measured by conventional techniques in 3 variants of pollination: 1) natural self-pollination; 2) artificial self-pollination; and 3) free pollination. Statistical data processing was performed using Microsoft Excel and the guidelines by B. A. Dospekhov.Results and conclusions. Highly self-fertile cultivars were identified, which may be recommended for breeders as sources of this trait: ‘Navlya’ (k-42228), ‘Dobrynya’ (k-42121), ‘Golubichka’ (k-32624), ‘Golosievsky velikan’ (k-44176), ‘Valentina’ (k-15631A), ‘Kozatskaya’ (k-44187), ‘Arapka’ (к-44175), ‘Kanakhama’ (k-44197) and ‘Fat’ (k-42509). High yield in the Northwest of Russia can be secured by cultivars that combine high self-fertility with large fruit size: ‘Valentina’ (k-15631A), ‘Vernisazh’ (k-43126), ‘Garmoniya’ (k-40677), ‘Dobrynya’ (k-42121), ‘Desertnaya Ogoltsovoy’(k-45670), ‘Joninai’ (k-43124), ‘Kanakhama’ (k-44197), ‘Karri (k-44172), ‘Mila’ (k-40673), ‘Sevchanka’(k-45551), ‘Sofievskaya’(k-43131), ‘Talisman’ (k-44183), ‘Yubileinaya Kopanya’ (k-44189), ‘Shalunya’(k-41988), and accession 2780-20-33 (k-15575A). It is shown that free pollination and artificial self-pollinationprovide a positive impact on the fruit setting level, fruit weight and seed productivity. Natural autogamy, on the contrary, tends to decrease the weight of berries and the number of seeds in them

Morphometric parameters of black currant berries and racemes under the conditions of Northwest Russia

Background. It is important to study morphometric parameters of productivity in cultivars because it allows us to identify the most productive cultivars and valuable genotypes with improved characteristics of the mechanical composition of berries for use in breeding practice.Materials and methods. Morphometric parameters of berries and racemes were assessed at Pushkin and Pavlovsk Laboratories of VIR in 2016–2018. Fifty-one black currant cultivars of various genetic and ecogeographic origin were the material for the research. Cvs. ‘Nara’ (for early cultivars) and ‘Peterburzhenka’ (for mid-season and mid-late ones), both listed in the State Register of Selection Achievements for Northwest Russia, served as the references. The research was conducted by conventional methods. Statistical data processing was performed using Microsoft Excel and guidelines.Results and conclusions. As a result of the research, valuable genotypes with the best morphometric parameters and cultivars for commercial and amateur gardening were identified. Large fruit size and stability of this trait were observed in cvs. ‘Yubileinaya Kopanya’ (k-44189), ‘Selechenskaya 2’ (k-42637), ‘Litvinovskaya’ (k-45542), ‘Fortuna’ (k-44194), ‘Partizanka bryanskaya’ (k-45548), ‘Sofievskaya’ (k-43131), ‘Raduzhnaya’ (k-45549), ‘Karri’ (k-44172), and accession 2780-20-33 (k-49788). Cvs. ‘Kozatskaya’ (k-44187) and ‘Perezvon’ (k-45589) develop 8 berries per raceme. The best cultivars with optimal combinations of the studied traits, suitable for large-scale cultivation and amateur gardening in Northwest Russia, are ‘Andreevskaya’ (k-49787), ‘Kazkova’ (k-44196), Raduzhnaya’ (k-45549), ‘Sevchanka’ (k-45551), ‘Selechenskaya 2’ (k-42637), Sofievskaya’ (k-43131), ‘Tatran Slava’ (k-44182), ‘Karri’ (k-44172), and ‘Yubileinaya Kopanya’ (k-44189). Correlations between individual morphostructural yield components were identified

Individual morphostructural components of yield in black currant cultivars

Background. The size of the fruit, its external attractiveness, along with other important characteristics of a variety, have always been important, especially for amateur gardening. Therefore, new cultivars replenishing the gene pool of black currant preserved by VIR, in addition to their main biological and economic characteristics (flowering and fruiting biology features, resistance to abiotic and biotic environmental factors), undergo mandatory testing for the quality of yield. The aim of this study was to assess individual morphostructural yield components in new cultivars added to the black currant collection of VIR.Materials and methods. The mechanical composition of berries and bunches was analyzed at Pushkin and Pavlovsk Laboratories of VIR in 2013–2015. Forty-one black currant cultivars of various ecogeographic origin were the material for the research. Cv. ‘Peterburzhenka’, listed in the State Register of Breeding Achievements for the Northwestern region of Russia, served as the reference. The research was conducted by conventional methods. Statistical data processing was performed using Microsoft Excel.Results and conclusions. Studying individual morphostructural components of yield made it possible to identify cultivars with the largest berries, the most stable fruit weight, and bunches containing 8–9 plump berries. The cultivars with the best combinations of the studied characteristics, suitable for large-scale cultivation and amateur gardening in the Northwest of Russia, are ‘Garmoniya’ (k-40677), ‘Kriviai’ (k-42517), ‘Ben Sarek’ (k-41435), ‘Joninai’ (k-43124), ‘Zhuravushka’ (k-40681), and ‘Shalynya’ (k-41988). Correlations between separate morphostructural yield components were identified, such as: fruit weight – fruit diameter (r = 0.92); fruit weight – number of seeds (r = 0.74); bunch length – number of flowers per bunch (r = 0.65), bunch length – number of berries per bunch (r = 0.52)

Properties of bright squeezed vacuum at increasing brightness

A bright squeezed vacuum (BSV) is a nonclassical macroscopic state of light, which is generated through high-gain parametric down-conversion or four-wave mixing. Although the BSV is an important tool in quantum optics and has a lot of applications, its theoretical description is still not complete. In particular, the existing description in terms of Schmidt modes with gain-independent shapes fails to explain the spectral broadening observed in the experiment as the mean number of photons increases. Meanwhile, the semiclassical description accounting for the broadening does not allow us to decouple the intermodal photon-number correlations. In this work, we present a new generalized theoretical approach to describe the spatial properties of a multimode BSV. In the multimode case, one has to take into account the complicated interplay between all involved modes: each plane-wave mode interacts with all other modes, which complicates the problem significantly. The developed approach is based on exchanging the (k, t ) and (ω, z) representations and solving a system of integrodifferential equations. Our approach predicts correctly the dynamics of the Schmidt modes and the broadening of the angular distribution with the increase in the BSV mean photon number due to a stronger pumping. Moreover, the model correctly describes various properties of a widely used experimental configuration with two crystals and an air gap between them, namely, an SU(1,1) interferometer. In particular, it predicts the narrowing of the intensity distribution, the reduction and shift of the side lobes, and the decline in the interference visibility as the mean photon number increases due to stronger pumping. The presented experimental results confirm the validity of the new approach. The model can be easily extended to the case of the frequency spectrum, frequency Schmidt modes, and other experimental configurations

ON REPRODUCTIVE BIOLOGY OF DISTANT HYBRIDS IN THE GROSSULARIACEAE FAMILY

Pollen morphology and pollen quality in distant hybrids of the genus Ribes L. were studied in the Russian North-West. A rather high fertility level was found in the studied hybrids, except for the triploid ‘Dlinnokistnaya CGL’. A connection between anomalous morphological features of the pollen wall structure and the pollen fertility level has been found in the studied samples

Projective filtering of a single spatial radiation eigenmode

Lossless filtering of a single coherent (Schmidt) mode from spatially multimode radiation is a problem crucial for optics in general and for quantum optics in particular. It becomes especially important in the case of nonclassical light that is fragile to optical losses. An example is bright squeezed vacuum generated via high-gain parametric down conversion or four-wave mixing. Its highly multiphoton and multimode structure offers a huge increase in the information capacity provided that each mode can be addressed separately. However, the nonclassical signature of bright squeezed vacuum, photon-number correlations, are highly susceptible to losses. Here we demonstrate lossless filtering of a single spatial Schmidt mode by projecting the spatial spectrum of bright squeezed vacuum on the eigenmode of a single-mode fiber. Moreover, we show that the first Schmidt mode can be captured by simply maximizing the fiber-coupled intensity. Importantly, the projection operation does not affect the targeted mode and leaves it usable for further applications.Comment: 10 pages, 9 figure

Non-conventional rule of making a periodically varying differentpole magnetic field in low-power alternating current electrical machines with using ring coils in multiphase armature winding

The paper presents methods of making a periodically varying different-pole magnetic field in low-power electrical machines. Authors consider classical designs of electrical machines and machines with ring windings in armature, structural features and calculated parameters of magnetic circuit for these machines