Contents of dry matter, soluble sol­ids, vitamin C and phenolic compounds in the pulp and peel of different cultivars of pear fruits

The aim of this work was to investigate and compare the amounts of biologically active compounds, dry matter and soluble solids in pulp and peels of four pear cultivars (‘Ksena’, ‘Beloruskaja pozdniaja’, ‘Alna’ and ‘Aleksandr Lucas’). The research was carried out at Vytautas Magnus University Agriculture Academy (Lithuania) in 2020. Four pear cultivars (‘Ksena’, ‘Beloruskaja pozdniaja’, ‘Alna’ and ‘Aleksandr Lucas’) were cultivated at a farm in the Joniškis District of Lithuania. Pears were grown following traditional pear production technology. The amounts of dry matter, soluble solids, vitamin C and fiber were determined using the standard method. The total content of phenolic compounds was determined using a Folin-Ciocalteu reagent with a UV/VIS spectrophotometer. The research results showed that significantly the highest amounts of soluble solids were found in the ‘Alna’ pear fruit pulp (14.25% f. w.). The ‘Alna’ peel sample had significantly the highest amount of total phenolic compounds (1290.99 mg 100 g–1 d. w.). The highest content of dry matter was found in the ‘Aleksandr Lucas’ pear fruit peel (24.67%). The ‘Aleksandr Lucas’ and ‘Beloruskaja pozdniaja’ pear fruit peel contained significantly the highest amounts of vitamin C (2.70 and 2.63 mg 100 g–1 f. w., respectively). The highest content of fiber was found in the ‘Ksena’ fruit peel (36.12% d. w.). The investigated pear peel sample had significantly higher amounts of dry matter, vitamin C, total phenolic compounds and fiber than the pulp. However, the pulp contains the highest contents of soluble solids.

Prevalence of Campylobacter spp. among imported broiler drumsticks and wings sold in Lithuania

The aim of this research was to estimate the prevalence of Campylobacter in imported broiler drumsticks and wings. During the one-year study period, 138 imported broiler samples (raw wings and drumsticks) were collected and tested from 3 different sellers. Campylobacter spp. were detected and isolated using traditional microbiological methods, identified using a multiplex polymerase chain reaction (PCR) method. The results of PCR products were analysed in agarose gel using electrophoresis. After an epidemiological study, C. jejuni and C. coli strains were selected and the prevalence of virulence genes was evaluated. The study identified Campylobacter spp. in 36 (26.1%) samples – 19 raw wings (27.9%) and 17 raw drumsticks (24.3%) samples were infected with these bacteria. Campylobacter spp. were most frequently detected in raw broiler samples during autumn (September–November) (47.2%) and winter (December–February) (41.6%) periods than spring (March–May) (5.5%) or summer (June–August) (5.5%). Contamination of products was not significantly impacted by the sale location (p > 0.05). The examination of virulence factors of Campylobacter spp. revealed that C. jejuni and C. coli strains contain 2 out of 3 virulence genes – CadF and CdtA. The CdtA gene was found in nearly all tested Campylobacter spp. strains isolated from broiler samples (94.4%).

Apple cultivars in Lithuania in 1820–1914

The oldest mentioned gardens in Lithuania are from the Middle Ages. However, the oldest lists of fruit tree cultivars were compiled only in the 19th century. The article presents systematised information on apple (Malus domestica Borkh.) cultivars recommended for cultivation and cultivated in Lithuania from 1820 to 1914. A total of 22 written sources in Polish, Russian and Lithuanian from the period that mention specific apple cultivars were analysed. A list of 165 old apple cultivars was compiled during the study. The apple cultivars mentioned in historical sources have been identified as contemporary apple cultivars or those described in other historical pomology sources. The original names of the old apple cultivars recorded in written sources are also provided. The compiled list of apple cultivars reveals characteristics of the development of apple orchards in the cultural context of this period.

Impact of different tillage on soil physical properties, CO2 emissions and winter oilseed rape yield

The investigation presents data on winter rape agrocenosis productivity, soil physical properties, and CO2 metabolism intensity using different tillages. The object of the research is the winter rape (Brassica napus L.) crop using different tillages. The aim of the study was to determine and compare the effects of different tillages and direct sowing on winter oilseed rape, soil physical properties and CO2 emissions. Methods of analysis. The studies have been carried out in accordance with established procedures. The methods used to apply the Stationary Single Factor Field Experiment were installed at the Vytautas Magnus University Experimental Station in 1988. The study factor is tillage systems: normal deep pruning at a depth of 23–25 cm in autumn (DP), control; shallow pruning at a depth of 12 to 15 cm in autumn (SP); deep loosening at a depth of 8 to 10 cm in autumn (DL); shallow loosening 13–25 cm (SL); direct seeding with cultivation up to 5 cm (NT). Results. For a long time, direct seeding into the stubble (with cultivation up to 5 cm) increases the resistance of the soil shear. During the whole investigation period, a lower CO2 concentration was observed in shallow loosening and direct seeding fields. Simplified tillages did not have a significant impact on the yields of winter rape.

The influence of aromatic amino acids on the chemical composition of mint plants genus (Mentha L.)

The aromatic amino acids, tryptophan, phenylalanine and tyrosine, are not only components of proteins, but also precursors of many compounds in plants that have a significant impact on their growth, development, reproduction and protective function against various abiotic and biotic factors. With the growing demand for plant-derived chemical compounds, much in vitro and in vivo research is being conducted to intensify the synthesis of these compounds or to change their qualitative composition in plants. The aim of the research was to evaluate the influence of aromatic amino acids on the chemical composition of different varieties of Mentha L. plants. The field experiment was conducted at Aleksandras Stulginskis University (ASU) in 2017–2019, since 2019 at the Vytautas Magnus University Agricultural Academy Experimental Station, which is located in Ringaudai Eldership, Kaunas District (coordinates 54 ° 53′ 08.9″ N, 23° 50′ 08.02″ E). The effect of different concentrations of amino acid solutions on the chemical composition of mints depended on the mint variety. Spraying with all amino acids solutions significantly increased the dry matter, crude fiber and crude ash content in M. spicata ‘Crispa’ mints while a positive effect of amino acids solutions on the protein content was found only in M. piperita ‘Granada’ mints sprayed only with 200 mg l–1 tyrosine solution, where the amount of protein increased significantly by 1.41-fold compared to that of non-sprayed plants. The intensity of the synthesis of photosynthetic pigments depended on the amino acid solutions used and the variety of mint. There were both inhibitory and stimulatory effects.

Plant growth regulator effects on sunflower parents and F1 hybrids

The need for augmented sunflower production requires finding new meth­ods and improving existing cultivation technologies to increase performance and resistance to stresses. The low performance of breeding and seed production lines is among obstacles to the rapid introduction of new and modern sunflower hybrids into production. The study purpose was to evaluate the individual responses of self-pollinating sunflower lines intended for breeding and seed production and of F1 hybrids, which were developed by crossing these lines, to plant growth regulators. It was found that the CMS-based lines had better yield elements and oil content in response to growth regulators compared to the lines based on normal cytoplasm. The plant growth regulators increased the heterosis effect in the experimental hybrids. The best response was observed in the threeline hybrid Skh808A/Kh1002B × Kh785V for all the studied parameters. The growth regulators strengthened a correlation between the 1000-seed weight and yield (r = 0.51–0.97). The oil content in seeds of F1 hybrids depended on the genotype and could be comparable both with the parent with a low content of oil and with the high-oil parent. Variations in the oil content in seeds depended on the type of growth regulator and soil/climatic conditions during the seed filling.

Changes in the condition of woodland key habitats

In Lithuania, key and potential key forest habitats (hereinafter (P)WKH) were inventoried for the first time during 2000–2004. A repeated inventory of existing and newly established habitats was carried out during 2013–2017. This study assessed changes in (P)WKH over a period of 10–15 years between the main and repeated inventory. The gathered long-term and numerous information on the key biological elements of (P)WKH, rare species (mosses, lichens, vascular plants, mushrooms, beetles and molluscs), negative factors and the most appropriate measures for the preservation of biological values were analysed. The results showed that over a period of 10–15 years, 90.5% of woodland key habitats (WKH) remained stable or improved, and the status of potential woodland key habitats (PWKH) remained stable or improved in 60.3% of all PWKHs. The most significant changes were identified in the scenarios of WKH change into potential and PWKH change into key habitats. According to the PKMB to WKH change scenario, all investigated biological elements had a significant increased tendency of 1.2–2.3 times. All investigated biological elements decreased 1.4–3.9 times according to the WKH to PKMB change scenario. During the 10–15 years period, most WKH and some PWKH confirmed their potential to conserve and enrich biodiversity in a relatively small area, thus ensuring the function of a sustainable forest landscape as rare species habitats and being part of a network of protected areas. Special attention should be given to the necessary measures for the conservation of (P)WKH biodiversity (protection against economic use and application of nature management measures), continuous monitoring of these areas, as well as the admission and implementation of the legal framework for forest habitats in the general forest management policy.

The use of crop sensors for precise fertilization

The paper presents the results of research on the use of ISARIA and OptRx sensors for the analysis of plant optical properties for precision fertilization. It was found that using the ISARIA and OptRx sensors of plant optical properties, it was possible to detect differences in the development of spring wheat crops. Consumption of OptRx mineral fertilizers in 2016 using precision fertilization of spring wheat and using plant optical analysis sensors was 3.5% higher, and in 2017 and 2018, respectively, 1.1 and 3.5% lower than in conventional intensive technology. Consumption of ISARIA mineral fertilizers in 2016 and 2018 using sensors were 0.5 and 0.6%, respectively, higher, and in 2017 it was 4.6% lower than in conventional intensive technology.

Susceptibility of spring barley varieties to fungal diseases and their economic value under chemical control

Studies on disease susceptibility of spring barley varieties important for the Lithuanian market were carried out at the Department of Plant Pathology and Protection of the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry in 2017–2019. The study is aimed to compare susceptibility of spring barley varieties grown in Lithuania to fungal diseases. The experiment was installed in a two-lane block: one lane was sprayed with fungicides and other lane was sprayed with fungicides two times. During the study years, powdery mildew, net blotch, spot blotch, ramularia leaf spot and leaf rust occurred in spring barley. Powdery mildew was the most prevalent in the variety ‘Grace’ – the AUDPC index of powdery mildew was on average 186.17, while in the least damaged variety, ‘Rusnė DS’, it averaged 0.48. The intensity of net blotch in the variety ‘RGT Planet’ was 1.38%, several times higher compared to that of the most resistant variety ‘Ema DS’ – 0.30%. The average intensity of spot blotch was 2% in the variety ‘Propino’, which was the most severely affected, and only 0.24% in the least affected variety ‘Luokė’. The application of fungicides resulted in the highest yield increase (1 t ha–1) in the spring barley variety ‘Luokė’.

Chemical composition and quality of sea buckthorn (Hippophae rhamnoides L.) berry processing products

Research on the quality of sea buckthorn (Hippophae rhamnoides L.) berry processing products was done at Vytautas Magnus University Agriculture Academy in 2019. For the studies, the juice was squeezed from the defrosted sea buckthorn berries, and was stored in the refrigerator until separated into three fractions: solids, oil (oil No. 1) and juice. The berry cake remaining after squeezing the juice was dried and filled with unrefined sunflower oil. After 2 weeks, the oil (oil No. 2) was separated from the cake. The aim of the research was to determine the chemical composition and quality indices of sea buckthorn berry processing products. The content of soluble solids, titratable acidity, vitamin C and total carotenoid content were determined by standard methods in sea buckthorn juice, solids, berry press cake and in oil No. 1 and No. 2. The acid value, iodine value, peroxides value, induction period and colour of sea buckthorn berry oil No. 1 and No. 2 were determined. The research data were analysed by the factorial analysis of variance (ANOVA). Arithmetical means and standard deviation of the data were calculated. Statistical reliability was assessed by Fisher’s LSD test (P < 0.05). The results showed that the solids had 1.3-fold higher soluble solids content, 1.1-fold higher vitamin C, 2.5-fold total carotenoid content and 1.0-fold higher titratable acidity compared to juice. Oil No. 1 was characterized by a 1.88-fold bigger content of vitamin C and 2.9-fold higher titratable acidity. The total carotenoid content was 8.7% higher in oil No. 2. Oil No. 1 was less resistant to oxidative degradation because the induction period of this oil was shorter by 0.45 h and for a 26% higher amount of free fatty acids. However, a 12% higher peroxide content was found in oil No. 2. Oil No. 1 was brighter; the intensity of red and yellow colour of this oil was more intense.