Effect of foliar application of a fertilizer containing silicon and calcium on the yield and technological quality of sugar beet roots

In the experiment carried out in Sahryń village (50°40′42″N, 23°47′35″E) in 2019–2020, the impact of threefold foliar application of Si and Ca-containing fertilizer, fourfold application of fungicides and the combination of both of these combinations on the yield and technological quality of sugar beet roots in conditions of strong infection pressure of Cercospora beticola Sacc. The effects were compared to the control. Triple foliar application of the fertilizer had a beneficial effect on the root, biological and pure yield of sugar. The biological and pure yield of sugar increased in the following sequence: control; 3x foliar application of the product with Si + Ca; 4x fungicide treatments; 3x foliar application of the product with Si + Ca + 4x fungicide treatments. A foliar application of silicon and calcium products can help implement a “field to fork” strategy.

Identification and molecular characterization of onion yellow dwarf virus (OYDV) in Allium cepa crops in Poland

Onion yellow dwarf virus is distributed worldwide significantly reducing yield of crops from the Allium genus. The aim of the study was the detection and molecular characterization of newly identified OYDV isolates infecting onions in Poland. The virus was detected by transmission electron microscopy and RT-PCR techniques using two pairs of diagnostic primers: OYDV-NibCPF1/R1 and OYDV-CPF2/R2. The specificity of obtained RT-PCR products was confirmed by Sanger sequencing and received viral coat protein sequence was used for phylogenetic analysis. The phylogenetic analysis was carried out using CP sequences of the new Polish onion isolate obtained in this study and 37 other sequences of OYDV retrieved from GenBank. The analysis revealed that the Polish OYDV isolate is the most similar to the OYDV isolates derived from onions from Argentina and Germany, which may indicate their common origin. Moreover, it was observed that the Polish onion and garlic isolates are very diverse and belong to different phylogroups.

Optimalization of multiresidue method for the determination of pesticide residues in fruits

The main aim of this study was to optimize the QuEChERS methodology for the comprehensive determination of pesticide residues using a simple and inexpensive gas chromatography equipped with selective detectors working simultaneously (GC-ECD/NPD). The method was validated in accordance with the SANTE/11945/2015 guidelines. Representative fruit matrices were chosen from the commodities group with high water content (apples), and with high acidity and high water content (strawberry) for a 160 compounds in the range of 0.005−0.02 mg/kg. The accuracy of the method was as required (recovery: 70–120%, precision: below 20%) for 135 active substances in apples samples and 137 in strawberries samples. The main advantages of the methodology include: good detector response linearity (R2 above 0.995), low limits of detection (0.005 mg/kg for more than 20 compounds, 0.01 mg/kg for about 120 compounds), possibility of simultaneous determination of a wide range of compounds (including some “difficult” ones) without use of a single residue methods. The simultaneous use of two selective detectors allows to obtain more data during a single dose of the sample and confirmation of the result for most compounds, which allows to prevent false positives ones.

Assessment of the germination capacity of soybeans depending on the pH of the substrate

Germination od three non GMO soybean cultivars: Abelina, SG Anser and Merlin was examined in a laboratory study as affected by pH level: 5.0; 5.5; 6.0; 6.5 and 7.0. The soybean seeds came from a field experiment carried out in 2017–2018. Analysis of germination capacity was based on two-factor analysis of variance in a completely randomized setting. Among the tested cultivar Abelina had the highest germination capacity. An application of pH from 6.0 to 6.5 contributed the most germinated seeds: 90.0 and 92.0%, respectively. The highest number of abnormally germinating seeds was observed in cultivar SG Anser and when the pH of the soil was 5.0 to 5.5. The numer of non-germinating seeds was higher in 2018 than 2017 and only in the cultivar Abelina did not differ significantly between years.

The effect of weed management method on weeds infestation, yield, storage ability and nutritional value of leek (Allium porrum L.)

In the years 2012–2014, at The National Institute of Horticultural Research in Skierniewice, research was carried out on determining the impact of various methods of weeding on leek yield, its storage stability and nutritional value after harvest and storage. In the field experiments the following methods were compared: mechanical treatments, mechanical treatments + growth stimulator, soil mulching with polypropylene and black foil and hand weeding. After harvest the leek were storage at the temperature 0°C for 124–150 days depending on the year and after the storage it was sorted as: marketable leeks and plants with diseases symptoms and rotten plants, and also leek’s natural weight loss was determined. After harvest and after storage, the content of dry matter, total sugars and soluble phenols in leeks was determined. The highest marketable yield immediately after harvest was obtained from plants mulched with black materials. After storage, the most marketable leeks were obtained from the control and hand weeded during cultivation. Chemical composition of leek was analysed after harvest and after the storage period. After harvest the highest yield from leek grown in black mulch were obtained and after the storage from control and hand weeding. Chemical analyses showed that the highest dry matter and total sugars contents were found in leek weeded by hand, and after storage mulched with black and polypropylene foil. After harvest, the highest content of soluble phenols was recorded in leek weeded mechanically and treated additionally with a growth stimulator, and after the storage – in mechanically weeded leeks.

Compost bacteria as potential agents in biological plant control

The assumptions of integrated pest management put great emphasis on the development of non-chemical methods which increases the interest in biological methods and the search for microorganisms that would be an alternative to the most frequently used fungicides. The aim of the experiments was the isolation of the compost bacteria, in vitro determination of their fungistatic activity against some pathogenic fungi of the genus Fusarium, Alternaria, Sclerotinia, Botrytis, Rhizoctonia and Pythium and identification of selected isolates. From the backyard compost, 44 bacterial strains were isolated and assessed for the fungistatic properties by the well diffusion method. The obtained results allowed for the selection of 12 isolates of compost bacteria, characterised by the broadest and the strongest fungistatic activity spectrum against tested fungi. Identification of bacterial isolates by: MALDI-TOF mass spectrometry and 16S rRNA gene sequencing methods showed their belonging to the species Bacillus subtilis, Alcaligenes faecalis, Stenotrophomonas maltophilia and Serratia liquefaciens.

Assessment of the PCR technique for identification of Bursaphelenchus mucronatus Mamiya & Enda 1979, B. xylophilus Steiner & Buhrer 1934 (Nickle 1970) and B. fraudulentus Rühm 1956 (Nematoda, Aphelenchoididae) in crude extract of nematodes isolated from wood

The pine wood nematode, Bursaphelenchus xylophilus Steiner & Buhrer 1934 (Nickle 1970) is the major causative agent of the pine wilt disease which has become devastating to Asian and European coniferous forests. These regions are also naturally occupied by two other native but nonpathogenic species, i.e. B. mucronatus Mamiya & Enda 1979 and B. fraudulentus Rühm 1956 which are closely related to the invasive B. xylophilus. Moreover, all these three species can colonize pine trees, and potentially be extracted from the same wood samples. Due to the cosmopolitan character and wide genetic variation within- and between existing populations the taxonomic distinction of these species based exclusively on their morphology is difficult or, almost impossible. The present quarantine regulations related to B. xylophilus require the most credible and simple methods which could allow for a possibly earliest detection and precise identification of this species in wood shipments and conifer forests stands. The main objectives of the presently reported research were to simplify the presently available procedures for possibly fast and precise detection and identification of B. xylophilus examined in the background of the remaining Bursaphelenchus species of the xylophilus group and other bacterio- and mycetophagous nematodes naturally present in the pine wood samples. The developed method is based on a direct examination of the crude nematode extract from wood samples and subsequent use of PCR technique with earlier designed specific reaction starters amplifying ITS1–28S rDNA regions.