The experiment was carried out in the Rhododendron breeding and testing nursery „Babīte” of the University of Latvia. The aim of the experiment was to evaluate how rooting of white flower deciduous rhododendron cuttings differed depending on propagation time. Cuttings for rooting were selected at three propagation times in 2014 and 2015. Rooting quality should be taken into account to obtain and develop good and viable planting material. Four white flower deciduous azalea varieties were used: ‘Babītes Astra’, ‘Pērlīte’, ‘Polārzvaigzne’ and ‘Rīta Zvaigzne’ (control). The rooting of cuttings showed similar results in both years. The lowest total growing rate results showed cultivar ‘Polārzvaigzne’ that can be set as the most difficult rooting variety. Winter hardiness was a problem and small amount of cuttings overwintered.

Pear (Pyrus communis) is one of the most common fruit crop in Latvia and pear orchards occupy approximately 200 hectares. Although European pear rust caused by Gymnosporangium sabinae (Dicks.) G. winter is not considered as the key problem in commercial pear orchards, severe damages have occurred during the last decade. Severe damages were mainly observed in home gardens or organic orchards. In recent years, the disease occurred also in some commercial orchards where applications of fungicides according to standard schemes appeared not to be sufficient for European pear rust control. The aim of this study was to evaluate current fungicide treatment schemes and their optimization for European pear rust control based on the pathogen life cycle. Data analysis showed statistically significant differences in disease severity among the years and it correlated with the time of first fungicide application and release of basidiospores.

The aim of the study was to analyse an average movement correctness scores of Latvian warmblood horse breed draught type stallions’ progeny and compare with scores of the sires. The data included progeny (n=184) of 15 actual sires. The average scores varied from 6.4 to 7.6 with significant difference (p is less than 0.05) between progeny of some stallions. The average score of progeny in some cases was lower than score of the sire, but stallion Madrepors had lower score than his progeny average scores on 1.63 points. Heritability for movement correctness was 0.35.

Legumes are important crop all over the world due to their protein content, possibility to fix atmosphere nitrogen and provide sustainable soil quality. Experiments were carried out to assess the role of symbiotic relationships on some plant characteristics (chlorophylls content, plant biomass, nodule weight, dehydrogenases activity, yield, protein content in plants and seeds). Results showed that the use of rhizobia may contribute to protein accumulation in seed, but certain strains effectiveness depends on soil properties and plant varieties. Plant and rhizobia interaction efficiency can be described with dehydrogenase activity. In order to obtain a more stable symbiotic nitrogen fixation effect, it is necessary to combine different rhizobia strains.

Melon (Cucumis melo L.) is an important horticultural crop. To contribute melon growth in Latvia, it is necessary to provide proper planting material. Valuable genetic material of Latvia’s melons has been obtained from Pure Horticultural Research Centre. The obtained genetic material was propagated from seeds of two seasons from 2014 to 2015 in Botanical Garden of Latvia University on opened field. Latgale`s melon lines 4(3), 5(2), 8, 14 were introduced from seeds in Murashige and Skoog medium and cloned two times. The main objective was to observe the morphological evolution and characteristics of Latgale`s melon clones in vitro. This method is particularly important for genetically homogenous clones reproducing for breeding needs. Line 4(3) of Latgale’s melon seeds showed the best results of all the other lines, and 2 of 10 seeds germinated. The seeds of Latgale`s melon lines 8 and 5(2) in vitro did not germinate. The more productive clone was the line 14 by releasing the 31 clone from one seed. The Latgale’s melon clones reproduce the roots without auxins and cytokinins added to the culture medium.

The main purpose of current experiments was to investigate extrusion temperature in whole-grain pasta production. Conventional rye (Secale cereale, cultivar ‘Kaupo’), triticale (×Triticosecale line 9405-23), organic hull-less barley (Hordeum vulgare line PR 3808.21) cultivated at Institute of Agro resources and Economics (Latvia) in 2014, and conventional winter wheat (Triticum aestivum cultivar ‘Zentos’) grain cultivated at LLU Research and Study farm „Peterlauki” (Latvia) in 2014 were used in the experiments. Wheat flour type 405 from JSC „Dobeles dzirnavnieks” (Latvia) was used for the flour blend obtaining. Wheat, rye, hull-less barley and triticale grain was grounded in the laboratory mill PLM3100/B (Perten, Sweden) obtaining fine whole-grain flour. In pasta production wheat flour type 405 was replaced with: (1) 30% of whole-triticale flour; (2) 20% of whole-rye flour; (3) 20% whole-hull-less barley flour; (4) 50% of whole-wheat flour. Pasta structure-mechanical properties showed that the extrusion temperature has a major influence on starch grain gelatinization process. Since the extruder temperature zones are divided into three parts, it is important to determine its proper distribution.

The influence of sous vide treatment (80 °C; 15 min) and high pressure processing (700 MPa; 10 min; 20 °C) on the sensory quality of cowpea (Vigna unguiculata (L.) Walp. ‘Fradel’) and maple pea (Pisum sativum var. arvense L. ‘Bruno’) spreads during 62-day storage at 5 °C was investigated in the research. Pulse spreads were filled in PA/PE and PET/ALU/PA/PP film pouches, packaged in vacuum and hermetically sealed. Four different pulse spreads were made of ground re-hydrated cooked pulse seeds to which salt, citric acid, oil and seasoning was added. Sensory quality (overall appearance, aroma, mouthfeel and taste) of pulse spreads during storage was evaluated by 6 experts using 5 point scale for each attribute; quality number was calculated for each sample. High pressure processing is able to ensure better sensory quality of cowpea and maple pea spreads during 62-day storage compared to sous vide treatment.

The use of different soil covers is well-known agricultural practice. All around the world people are using mulch to increase vegetable growth and yield. The use of plastic film helps to get cleaner fruits and to limit weed growth. There have been conducted studies in Latvia on the use of various synthetic mulch materials in strawberry cultivation, but there is not enough information about the effects of coloured plastic film soil cowers’ impact on cucumbers. The aim of the study was to determine the effect of coloured polyethylene mulch’s on yield of cucumbers cultivars ‘Pioneer’ F1 and ‘Madita’ F1. The research was conducted during the vegetation period of years 2014, 2015 and 2016. The experiments were established in gardening cooperative „Atpūta” owned summer cottage area in Svēte parish, Jelgava Municipality. In all experimental years, cucumbers were planted on 18 June, when the first true leave developed (BBCH 11). Six different coloured polyethylene films were used: yellow, red, blue, black and white film. A field without polyethylene coverage was a control group. The test was conducted in two replicates, including four plants. The largest harvest was obtained from the yellow mulched plots. White polyethylene film is not recommended for soil mulching due to decrease of cucumber yield in all experimental years. The effect of films’ colour depended on climatic conditions in growing season.

Wheat (Triticum aestivum) leaf diseases are important risk factors in wheat cropping system. Growing of resistant cultivars is one of the basic methods in the Integrated Pest Management System. The aim of this study is to evaluate development of wheat diseases depending on genotypes. Investigations were carried out at the Study and Research farm „Peterlauki” of the Latvia University of Agriculture. Development of diseases was evaluated in 16 different genotypes, 6 of them were created at the Stende Research Centre of the Institute of Agricultural Resources and Economics, but others came from Bulgaria. Severity of diseases was evaluated weekly and AUDPC (area under diseases progress curve) was calculated to characteristic impact of diseases during the whole period of vegetation. Development of mildew mostly depended on genotype. Observed differences were significant; in general genotypes created in Latvia have higher resistance. Severity of tan spot and Septoria leaf blotch varied less; however, differences among genotypes were essential. Yellow rust was observed only in several genotypes. Latvian genotypes were more resistant against Blumeria graminis and Zymoseptoria tritici, but more susceptible against Pyrenophora tritici-repentis.

In recent years, hull-less barley (Hordeum vulgare L.) has been included in food production in Europe due to its diverse health benefits. The main objective of this study was to evaluate hull-less barley yield and grain quality grown under different climatic conditions in Latvia and Norway. Preliminary results indicate that hull-less varieties have significantly (p is less than 0.05) lower yield potential than hulled varieties regardless cereal species and species origin. Higher content of healthy substances such as protein and β-glucan content were observed in hull-less barley genotypes in comparison to hulled ones, but these genotypes are more responsive to environmental and management changes.