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Abstract

The objective of the research was to create a model which defines the relation between a fundamental contact area of a seed and the pressure force, water content in a seed and its geometrical dimensions with application of artificial neural networks (SSN). Computer program Statistica Neural Networks v. 6.0. was used for formation of a neural model. Tests were carried out on Roma wheat seed and Dańkowskie Złote rye with six various water contents: 0.11 0.15 0.19 0.23 0.28 0.33 (kg·kg-1 dry mass). Caryopses were loaded with eight values of compression force - from 41 N to 230 N. Multiplicity of iterations was 5. Seed material was moistened to obtain a specific water content. Each seed was loaded with compression force with respectively growing values: 41N, 68N, 95N, 122N, 149N, 176N, 203N and 230N. A four-layer network of Perceptron type with 10 neurons in the first and 8 neurons in the second hidden layer was selected as a model which the best defines the contact area of grain seeds loaded with axial force at various moisture levels. This network has 4 inputs (water content, pressure force, thickness and length of caryopses) and one output (elementary contact area of rye and wheat seeds). Comparison of the neural model with empirical formulas obtained from nonlinear estimation proved a considerable higher precision of the first one.

Abstract

The seed orchards (SO) serve possibilities to collect seeds from the selected genotypes or to create artificial population throughout the controlled crossing of the target genotypes. Therefore, the seed material obtained from the clonal and seedling seed orchards offers unique opportunity to improve the genetic value of seeds. Thus, the seed orchards are considered as an important part of the forest seed base being the key object for both modern forestry and forestry research. This paper outlines the forest breeding activities associated with the seed production in the seed orchards in Ukraine over the last 70 years. During this period, the different aspects related to the establishment and management of the seed orchard were studied. In these processes, many failures had occurred, their causes and consequences were described. These main breeding activities were reported considering plain and mountain regions of Ukraine as well as specific aspects of the reproduction of the main forest tree species. As of 2019, the total area of the clonal seed orchards (CSO) reached 1040.3 ha, while seedling seed orchards (SSO) only 273.7 ha. The results of research on the growth, reproductive development, the morphology of the plus trees clones in the SO were generalized. The article on the current problems and challenges for Ukrainian forestry mainly related to forest tree breeding and there was also focus on forest seed industry. For the main forest trees species (Scots pine, English oak and other), targeted breeding programs should be developed. It is relevant to create the genetic bank of the forest seeds.

Summary

Introduction: Fresh herbs of poison hemlock (Conii maculati herba) are used in homeopathy. The plant is also used in pharmacological and toxicological studies. There are few articles on seed germination capability in available literature.

Objective: The aim of the research was evaluation of Conium maculatum seed germination.

Methods: Germination studies of C. maculatum L. were carried out according to methodology by ISTA.

Results: It was confirmed that the germination capability of the described species is dependent on access to light and temperature fluctuations. In the first year after harvest, the highest percentage of germinating seeds was found in the winter months (January–February).

Conclusion: The seeds stored in an unheated room still germinated in the fifth year after harvest.

The first potato varieties that reached the territory of Latvia were empirically selected clones from genetically diverse material brought from South America to Europe. In the 19th century, when agricultural production rapidly developed, the demand for high yielding potato varieties suitable to local growing conditions increased. Therefore, potato variety evaluation trials were set up. Scientifically- based potato breeding in Latvia was launched by P. Knappe. The potato breeding programme in Priekuïi Plant Breeding Station was started in 1931, and has still continued. Several breeding methods were used by potato breeders Ç. Knape, V. Gaujers, G. Bebre and others in Priekuïi. Potato breeding for short periods was carried out in several other places in Latvia: Stende, Carnikava, and Lejaskurzeme. The method of elimination of diseases in potato seed material and high quality seed material production was implemented in Priekuïi. More than 60 potato varieties have been created in Latvia, some of them were and still are in demand in agricultural production.

Abstract

The study involved 121 samples of the common weed, Lactuca serriola L. (prickly lettuce), representing 53 populations from Sweden and Slovenia. The seed materials, originating from different habitats, were regenerated and taxonomically validated at the Department of Botany, Palacký University in Olomouc, Czech Republic. The morphological characterizations of the collected plant materials classified all 121 samples as L. serriola f. serriola; one sample was heterogeneous, and also present was L. serriola f. integrifolia. Differences in the amount and distribution of the genetic variations between the two regions were analyzed using 257 amplified fragment length polymorphism (AFLP) and 7 microsatellite (SSRs) markers. Bayesian clustering and Neighbor-Network were used for visualization of the differences among the samples by country. Under the Bayesian approach, the best partitioning (according to the most frequent signals) was resolved into three groups. While the absence of an admixture or low admixture was detected in the Slovenian samples, and the majority of the Swedish samples, a significant admixture was detected in the profiles of five Swedish samples collected near Malmö, which bore unique morphological features of their rosette leaves. The Neighbor-Network analysis divided the samples into 6 groups, each consisting of samples coming from a particular country. Reflection of morphology and eco-geographical conditions in genetic variation are also discussed.

Abstract

The sub-tropical species, Eucalyptus longirostrata (formerly E. punctata var longirostrata) and Corymbia henryi were investigated as alternative species for growth on the Zululand coastal plain in South Africa. Provenance/progeny trials were established in 2001 at two sites, namely, Nyalazi and Kwambonambi. The seed material purchased from the Commonwealth Scientific and Industrial Research Organization in Australia in 2000 included six provenances of E. longirostrata and five provenances of C. henryi. Six-year diameter at breast height measurements were completed in 2007. Individual narrow-sense heritability coefficients for diameter growth varied from 0.30 to 0.58 for both species, with heritabilities being higher at the drier Nyalazi site. Heritabilities and breeding values were calculated prior to making selections in field. A total of 143 selections were made in the E. longirostrata trials, and 113 in the C. henryi trials during 2008. Predicted gains for the next generation range from 2.8 cm (20%) to 6.1 cm (61%) increase in diameter for E. longirostrata, and 3.4 cm (23%) to 5.4 cm (49%) increase for C. henryi, depending on site and selection scenario. Provenance differences were evident in E. longirostrata at both sites; however, there were no significant differences between the C. henryi provenances of Australian origin. The top families of both species performed better than the hybrid controls at the Nyalazi site, indicating that both E. longirostrata and C. henryi are viable alternative species for successful growth on the drier sites of the Zululand coastal plain.

Abstract

Due to the fact that wheat varieties are different, they also have different temperature requirements. The present paper aims to find the most suitable seedlings that can germinate in an area with climatic conditions well below the optimum for germination of seeds. The observed temperatures were between 0 °C and 5 °C for the studied wheat varieties. The varieties analyzed were Miranda, Boema 1, Litera, autumn wheat varieties, created in our country.

The research was carried out by the controlled exposure method at low temperatures under laboratory conditions. During the study, the most important characteristics that can confirm the quality of seed material, namely germinative energy and faculty, were followed. Besides, we have also analyzed the elements of seed vigor, namely the length of the coleoptile, the root length and the weight of the germ, because I consider that these are key factors in determining the quality of the seeds.

The results obtained showed that low temperatures influenced moderately to strongly seeds germination capacity as well as the elements of vigor.

Phytophthora infestans Populations in Latvia

Potato late blight caused by Phytophthora infestans (Mont.) de Bary is one of the most investigated plant pathogens. However, problems with disease control have increased in recent years, which plant pathologists have explained by its ability of forming oospores in potato leaves. Consequently, the P. infestans population over the world has become more aggressive and virulent and late blight on potato stems is common. Oospores could be found in field conditions in potato leaflets with two or more separate spots. In Latvia the P. infestans mating type A2 was found in the 1980s. A laboratory experiment on the formation of oospores in Latvia was started in 2002. The total number of collected samples was 215. The samples were collected from potato trial fields, conventional fields and from private gardens in different regions of Latvia. Many potato leaflets with two spots were observed at the end of the growing season when the disease severity exceeded 50%. The results showed that the formation of oospores on potato leaflets in the field took place in the P. infestans population in Latvia. Oospores were found in 80-94% of the investigated cases. The occurrence of oospores means that plant rotation and certified seed material are important measures for potato late blight control and the usage of fungicides may not be effective.

Abstract

The problem of phosphorus discharge is related to environmental protection and food security. Struvite crystallization is a useful technology for phosphate recovery from wastewater. In the research, struvite crystallization process with CO2 degasification continuous U-shape reactor (CUSR) was application for phosphate recovery from animal manure wastewater. The result indicated PO4 3--P recovery ratio could achieve 47-53% without magnesium addition when CUSR hydraulic retention time controlled at 60 min. With extra magnesium addition, PO4 3--P recovery ratio could significant achieve 80-86% at magnesium addition amount 57.5 mg/dm3. PHREEQC modeling predictions trend of struvite crystallization was close to CUSR experimental results. The modeling calculation can provide a theoretical guide for operational parameters design. For seeding technology, high phosphate recovery efficiency was obtained and preformed struvite was the most effective seeding material. Surface characterization analysis demonstrated the dominant composition of chemical solids was struvite. Water extraction analysis indicated chemical solids recovery from animal manure wastewater could release PO4 3--P slowly and be available as slow-release fertilizer.

The State Priekuïi Plant Breeding Institute (previously Wenden, Cçsis or Priekuïi Experimental and Breeding Station) started its operation in 1913. The main aims of research have remained the same for the last century: to provide knowledge on crop management and to create crop varieties suitable to local growing conditions and farming systems, acceptable to consumer requirements. Supply to farmers of high quality seed material of cereals, potato, pea, clover and grasses is an essential part of the scope. Overall, 31 crop species have been involved in a wide range of studies. More than 100 different crop varieties have been bred since the beginning of the 20th century. Potato varieties ‘Brasla’, ‘Agrie Dzeltenie’, winter rye variety ‘Kaupo’, pea varieties ‘Vitra’, ‘Retrija’, barley variety ‘Idumeja’ and several clover and grass varieties are widely grown in farmers’ fields. The first hulless barley variety in the Baltic States, ‘Irbe’, and winter triticale variety ‘Inarta’ have been bred in the Institute recently. Long-term crop rotation trials have been run for more than 50 years. A number of outstanding scientists and agronomists have worked in the Institute: potato breeders E. Knappe and V. Gaujers, cereal breeders J. Lindermanis, M. Gaiíe, and M. Sovere, grass breeders P. Pommers, A. Apinis, and I. Holms, pea breeder M. Vitjaþkova, researchers on crop management R. Sniedze and V. Miíelsons, research manager and director U. Miglavs and others