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The assessment of the weed infestation effect on biomass yield of Miscanthus × giganteus in the first year of its commercial yield was conducted on two types of soil with different productive ability – Luvic Chernozem and Calcic Gleysol. The formed mass of weeds was higher on Luvic Chernozem and the infestation had grown according to the stages of Miscanthus growth. The biomass of weeds depended on the planting density of Miscanthus as well as on the weather conditions during the studied years. Weed infestation of crops very significantly influenced the formation of aboveground biomass of Miscanthus, so that the yields in the first year of commercial harvesting in the control where the weeds were removed manually were significantly higher compared to the crops in which weeds were not removed. The obtained results showed that weeds significantly affect the initial growth and development of Miscanthus plants that are, in general, slow, especially in the year of the crop establishment. The study evaluates the impact of a manual method of suppression and weed infestation of crops on the commercial yield of Miscanthus.

The critical time for weed removal (CTWR) is a period in the crop growth cycle when weed control must be initiated to prevent yield losses. Knowing the CTWR is useful for making decisions about the timing of weed control and in achieving efficient herbicide use from both biological and economic perspectives. Field studies were conducted in 2008 and 2009 at three locations in Serbia and one location in the USA to determine the CTWR in imidazolinone (IMI)-resistant sunflower grown with and without application of pre-emergence (PRE) herbicide. A four-parameter log-logistic model was fitted to data relating relative crop yield to increasing duration of weed presence. The CTWR without PRE herbicide treatment ranged from 14 to 26 d after emergence (DAE) corresponding to the V3 (three leaves) to V4 stages compared to 25 to 37 DAE, which corresponded to the V6 to V8 stages with PRE herbicide. The CTWR in IMI-resistant sunflower grown with PRE herbicide can be delayed by an additional 6 to 12 d compared to the crop grown without PRE herbicide under the present experimental conditions. The practical implication of this study is that the use of PRE herbicide could extend post-herbicide treatments by another 6 to 12 d with respect to the critical time required for weed removal without PRE herbicide in IMI-resistant sunflower.

A three-year trial (2003-2005) was conducted under agro ecological conditions of Timočka Krajina (the experiment farm of Technological Research Center in Zaječar). Research object were six malting barley genotypes, which were top-dressed with the following amounts of nitrogen in the course of growing season: 40, 60, 80 and 100 kg ha-1. A non-fertilized variant served as a control. The obtained results indicated that the tested genotypes reacted to increased amounts of nitrogen by changing their morphological and biological characteristics as well as the technological values of grain. The effectiveness of the applied nitrogen depended significantly on the distribution of rainfall in periods of highest water uptake by malting barley

The experiments were conducted in four locations in Serbia: Valjevo, Kucevo, Nova Pazova and Surduk in 2012 and 2013. A working hypothesis that growing conditions would not affect the rutin content in buckwheat leaves was set up. The content of rutin in leaves of buckwheat was determined by the HPLC/DAD technique, using the external standard calibration method. Out of the basic biometric parameters, average value, variance, and the variation coefficient were estimated. Results were processed by the analysis of variance for the factorial experiment. The analysis of variance showed existence of significant differences in the rutin content, over locations, but only in the first year of testing. The average content of rutin in the first and the second year was 3.30% and 2.61%, respectively, and in both years of testing it amounted on average to 2.82%. The variation in the rutin content was larger in the second year of testing. On the other hand, this variation was lower in the first year (5.3-29.0%) in comparison to the second year (16.2-28.6%). Relatively lower rutin contents were recorded in samples collected at lower-altitude locations.

Response of 16 oilseed rape genotypes to B (boron) toxicity was analyzed by comparing the results of two experiments conducted in a glasshouse. In Experiment 1 plants were grown in standard nutrient solutions with 10 µMB (control) and 1000 µM B. Relative root and shoot growth varied from 20-120% and 31-117%, respectively. Variation in B concentration in shoots was also wide (206.5-441.7 µg B g-1 DW) as well as total B uptake by plant (62.3-281.2 µg B g1). Four selected genotypes were grown in Experiment 2 in pots filled with high B soil (8 kg ha-1 B; B8). Shoot growth was not affected by B8 treatment, while root and shoot B concentration was significantly increased compared to control. Genotypes Panther and Pronto which performed low relative root and shoot growth and high B accumulation in plants in Experiment 1, had good growth in B8 treatment. In Experiment 2 genotype NS-L-7 had significantly lower B concentration in shots under treatment B8, but also very high B accumulation in Experiment 1. In addition, cluster analyses classified genotypes in three groups according to traits contrasting in their significance for analyzing response to B toxicity. The first group included four varieties based on their shared characteristics that have small value for the relative growth of roots and shoots and large values of B concentration in shoot. In the second largest group were connected ten genotypes that are heterogeneous in traits and do not stand out on any characteristic. Genotypes NS-L-7 and Navajo were separated in the third group because they had big relative growth of root and shoot, but also a high concentration of B in the shoot, and high total B uptake. Results showed that none of tested genotypes could not be recommended for breeding process to tolerance for B toxicity. [Projekat Ministarstva nauke Republike Srbije, br. OI 173028

Forgotten or neglected arable land plants, such as buckwheat, are becoming increasingly important in crop production. Grain and one seed nuts are in the usage for humans and domestic animals diet. On the fields of the Institute of Field and Vegetable Crops, Backi Petrovac, researches were conducted in terms of conventional (2010-2012) and organic cropping systems, 2012. Analysis of the average yields showed that Novosadska buckwheat variety achieved a statistically significantly higher yield in 2010 th (2,996 kg ha-1) compared to the 2011 th and 2012 th (p <0.01). The year showed statistical significance based on the analysis of variance. The average yields of Novosadska buckwheat variety, the variant with foliar fertilization in the conventional cropping system, were significantly higher compared with the control. The average yields amounted 1.395 kg ha-1 and were higher by 214 kg ha-1 , or 18.12% compared to the control. The average plants height was 144 cm. 1000 grain weight was on the average of 23.72 g for the entire experiment. Average yields in the organic cropping system were higher in variants with foliar fertilization (1322 kg ha-1) by 7% compared to the control and plants were higher by 7.28%. Plants were higher in the organic system of cultivation by 13 cm, or 9% compared with plants grown in conventional cropping system, while the yields fell for 73 kg ha-1 , respectively by 5.52%. Foliar fertilizers proved to be a possible method for yield, 1000 grain weight and plant height increasing in conventional and organic cropping systems.