Seed aging and deterioration affect seed vigor and viability. The characteristics of the chemical composition of oil crops seed are related to specific processes occurring in the seed during storage. This study was performed to examine the changes in seed vigor of different sunflower and soybean genotypes under controlled and conventional (uncontrolled) conditions of natural aging for six and twelve months. Obtained results show that the degree of seed damage and the ability of seed to resist the negative effects of aging were influenced by duration and type of storage, as well as seed characteristics of the tested genotypes. The most valuable vigor test for both sunflower and soybean was cold test.

Changes occurring in seed during aging are significant as far as seed quality and longevity are concerned and are a consequence of the effects of different storage conditions. The chemical composition of seed with high oil content is related to specific processes occurring in seed during storage. In this trial, sunflower and soybean genotypes developed in Novi Sad were submitted to accelerated aging for three and five days, and natural aging for six and twelve months, under controlled and conventional (non-controlled) conditions. The obtained results showed that preservation of seed viability depended on storage condition and duration, as well as plant species. Accelerated aging test can be used to predict the length of storage life of sunflower and soybean seed. In comparison to sunflower seed, soybean seed is more sensitive to damage and reduced germination during storage.

Soybean time of flowering and maturity are genetically controlled by E genes. Different allelic combinations of these genes determine soybean adaptation to a specific latitude. The paper describes the first attempt to assess adaptation of soybean genotypes developed and realized at Institute of Field and Vegetable Crops, Novi Sad, Serbia [Novi Sad (NS) varieties and breeding lines] based on E gene variation, as well as to comparatively assess E gene variation in North-American (NA), Chinese, and European genotypes, as most of the studies published so far deal with North-American and Chinese cultivars and breeding material. Allelic variation and distribution of the major maturity genes (E1, E2, E3, and E4) has been determined in 445 genotypes from soybean collections of NA ancestral lines, Chinese germplasm, and European varieties, as well as NS varieties and breeding lines. The study showed that allelic combinations of E1–E4 genes significantly determined the adaptation of varieties to different geographical regions, although they have different impacts on maturity. In general, each collection had one major E genotype haplogroup, comprising over 50% of the lines. The exceptions were European varieties that had two predominant haplogroups and NA ancestral lines distributed almost evenly among several haplogroups. As e1-as/e2/E3/E4 was the most common genotype in NS population, present in the best-performing genotypes in terms of yield, this specific allele combination was proposed as the optimal combination for the environments of Central-Eastern Europe.

Soybean plant density is an important factor of successful agricultural production. Due to the high number of plants per unit area, early plant overlapping and eventual plant loss, the estimation of soybean plant density in the later stages of development should enable the determination of the final plant number and reflect the state of the harvest. In order to assess soybean plant density in a digital, nondestructive, and less intense way, analysis was performed on RGB images (containing three channels: RED, GREEN, and BLUE) taken with a UAV (Unmanned Aerial Vehicle) on 66 experimental plots in 2018, and 200 experimental plots in 2019. Mean values of the R, G, and B channels were extracted for each plot, then vegetation indices (VIs) were calculated and used as predictors for the machine learning model (MLM). The model was calibrated in 2018 and validated in 2019. For validation purposes, the predicted values for the 200 experimental plots were compared with the real number of plants per unit area (m2). Model validation resulted in the correlation coefficient—R = 0.87, mean absolute error (MAE) = 6.24, and root mean square error (RMSE) = 7.47. The results of the research indicate the possibility of using the MLM, based on simple values of VIs, for the prediction of plant density in agriculture without using human labor.

The objective of this study was to examine the effect of primers on seed quality parameters using different starting values of germination. For this purpose, ten soybean lines selected at the Institute of Field and Vegetable Crops, Novi Sad were evaluated. The starting values of germination ranged between 48% and 89%. Seeds were surface sterilized with 3% sodium hypochlorite and immersed in different primers: 1% potassium nitrate, 1% potassium chloride and 1% hydrogen peroxide. Untreated seeds were used as the control. The obtained results revealed that the effects of priming depended on soybean line and treatment, whereas the efficiency of this pre-sowing treatment was not affected by the starting value of seed germination. Some lines responded favorably to immersion, while in others priming had an inhibitory effect, causing a significant decrease in germination. There was an increase in germination up to 12% or a decrease up to 11%, depending on line and treatment. Lines that were positively affected by this method also exhibited increased values for other germination parameters: mean germination time (MGT) and time to 50% germination (T50). Lower values of MGT and T50 were observed in lines which showed a negative response to priming and a decrease in germination, but also a more rapid radicle protrusion, as compared to the control.In conclusion, there is no universal applicability of one single primer as it might cause a negative response in some lines and thus reduce seed quality.

The aim of the research was to test the effect of foliar-applied solutions of ascorbic acid (AsA), glycine betaine (GB), salicylic acid (SA) and water as a second control on the yield and seed germination of the soybean (Glycine hispida (Moench) Maxim.) cultivar 'Sava' as well as their influence on the content of N, P, K and Ca in soybean seeds, and to estimate the intensity of lipid peroxidation and free proline content in soybean seedlings. The plants were treated with the solutions twice. The 1 st spray treatment was done at growth stage 6: flowering (main shoot), when first flowers opened (sporadically in population), and the 2 nd spray treatment was done at growth stage 7: development of fruits and seeds, when the first pod had reached final length of 15-20 mm. Foliar application of the solutions had a significant impact on seed yield and seed germination in both years of the experiment. In a favourable year 2016, treatments with ascorbic acid, glycine betaine and salicylic acid solution significantly increased seed yield by 6.21-9.67%. However, in an unfavourable year 2017, the effect was significantly greater with the application of water (yield increase 6.48%), while the application of glycine betaine solution even reduced the seed yield. In a favourable year 2016, treatments with ascorbic acid and salicylic acid solution significantly increased seed germination by 7% and 8%, respectively. In an unfavourable year 2017, also only ascorbic acid and salicylic acid significantly increased seed germination by 11% and 9%, respectively. However, when using cold test, when the seed was exposed to a low temperature of 10°C for 7 days and then placed under optimal seed germination conditions for 4 days, ascorbic acid and glycine betaine solution reduced seed germination in both experimental years. Therefore, further research is needed on the methods designed to increase seed germination of soybean, both in favourable and adverse conditions in Serbia.

The objective of this paper was to examine the effect of seed lot, sowing date, and priming on germination and vigour of soybean seed. Three different seed lots of an old soybean variety (Lot 1, Lot 2, Lot 3) created at the Institute of Field and Vegetable Crops in Novi Sad were used. There were three sowing dates: 10 April, 20 May and 20 June. KNO 3 (1%), H 2 O 2 (0.1%), GA 3 (0.075%) and distilled water were used as primers. The results showed that soaking the seed prior to sowing, so called priming, positively affected seed germination and vigour in all three lots and with all three sowing dates. The best effect was accomplished with Lot 1 and sowing on the third date. With regards to primers, the best effect was achieved with the application of KNO 3 and H 2 O 2 solutions. Research has shown that even soaking the seed in distilled water, which is a simple, cheap, and ecological method of priming, in most cases leads to improvement of germination and vigour of soybean seed.

The aim of the research was to test the effect of pulsed electromagnetic field (PEMF) on soybean seed germination and yield depending on specific field conditions, years of study, exposure duration and frequency. Field trial was conducted on an experimental field of Institute of Field and Vegetable Crops in Novi Sad, Serbia in 2010-2013. Seeds of the soybean (Glycine hispida (Moench)) medium-early cultivar ʻValjevkaʼ were exposed to the PEMF therapy using the impulse generator and strip. Low-frequency (16, 24, 30 and 72 Hz) PEMF was used in the duration of 0, 30, 60 and 90 minutes. Research results indicate that this method can increase seed germination up to 8.00% and yield by 960.5 kg, or 21% in field conditions, which is a significant increase and a solid basis to introduce this practice, primarily in organic production with a very limited use of seed treatment preparations. However, the practice can have an inhibitory effect under an unfavourable combination of exposure duration and frequency. The obtained data were processed using the analysis of variance of three-factorial trials considering all years of study. Due to different meteorological conditions in the study years, analysis of variance was conducted for each year of study and correlations between the tested traits were examined.