Influence of Total Production on the Planting Structure of Significant Vegetable Crops in the Republic of Serbia

Summary The purpose of this paper is to examine, on the basis of the total production and distribution area parameters analyzed, a potential relationship between the actual production of major vegetable crops in Serbia in the current year and the following year’s distribution of planting areas devoted to the crops considered. The analysis was performed for the period 2005-2019. The results obtained indicate that the current year’s production of certain vegetable crops such as potatoes, cabbage, kale, peppers and beans affect the following year’s distribution of their planting areas.

Profitability and Impact of Inorganic Fertilizers on the Maize Production in Ekona, Cameroon

Summary Declining soil fertility and low fertilizer use are the major abiotic factors limiting the maize production in Cameroon. Therefore, the design and introduction of appropriate fertilizer schemes, which would improve maize yields and provide incentives for smallholder farmers, are considered imperative. In 2018, a field experiment was conducted on the farm of the Institute of Agricultural Research for Development (IRAD) in Ekona, the south-west region of Cameroon, to investigate the profitability and impact of inorganic fertilizers on maize production. The experiment was laid out in a randomized complete block design with four replications and four treatments, using different fertilizer rates per hectare in each treatment (namely unfertilized control (T1), 50 kg urea + 50 kg N-P-K (T2), 100 kg urea + 100 kg N-P-K (T3) and 150 kg urea + 150 kg N-P-K (T4)). The results obtained indicate that all the maize growth parameters (plant height, number of leaves per plant, stem girth and leaf area) and yield components considered (cob length, cob diameter and test weight of 100 grains) were significantly (P < 0.05) higher in T4 than T1. The grain yields recorded ranged from 4.09–5.88 t ha−1 and were also statistically (P < 0.05) higher in T4 than T1. The incremental income based on the fertilizer use was the highest in T4, followed by T3 and T2. The value cost ratio (VCR) was greater than 2 in all the treatments and was found to be highest in T2 (3.15), followed by T4 (2.52) and T3 (2.49). As T2, T3 and T4 did not differ statistically (P > 0.05), all the fertilizer rates considered were economically viable, but T4 provide the most cost-effective due to its higher grain yields and incremental income.

Effect of Partial Substitution of Corn with Whole-Grain Wheat in Fattening Lamb Diets on their Growth Performance

Summary Wheat grain is commonly used for animal feeding in some regions while it is rarely used in others. Its nutrient composition is quite similar to more commonly used corn grain, but there are some concerns regarding its effect on animal performance and health. However, it appears that usage of wheat grain in animal feeding is dominantly affected by economic rather than nutritional reasons. When used with caution, wheat can be a good alternative to corn. In order to test this, 20 Wurttemberg lambs, three months old, were randomly separated in two groups and fed diets containing 600 g of corn grain, or 300 g of corn grain and 300 g of wheat grain, for a period of one month. The used grains were whole, non processed grains. Two diets contained the same commercial protein supplement and alfalfa hay was offered ad libitum. Both groups accepted their experimental diet well and readily consumed the amounts offered. No health problems were observed. Growth rate was higher in male than in female lambs, but was not affected by wheat inclusion.

Allelopathic Properties of Hemp

Summary Allelopathic effects of different plant allelochemicals have become the focus of studies that aim to determine new pesticidal compounds. Plant extracts with different chemical compositions can be obtained using different methods of extraction, whereas studies dealing with allelopathic properties use biotests to obtain fast and precise results. Such studies were undertaken after noticing the allelopathic effects of industrial hemp (Cannabis sativa L.) on the surrounding crops. Trials that involve the application of hemp extracts obtained by different methods resulted in determining the hemp allelopathic effects on Stellaria media (L.)Scop., Beta vulgaris ssp. vulgaris var. vulgaris, Lupinus albus L., corn (Zea mays L.), Cyperus rotundus L., Matricaria recutita L., Lepidium sativum L., lettuce (Lactuca sativa L.), rapeseed (Brassica napus L.), wheat (Triticum aestivum L.), rye (Secale cereal M. Bieb.), Ambrosia artemisiifolia L., Chenopodium album L., and Sorghum halepense L..

Repellent Activity of Cymbopogon citratus Essential Oil Against Four Major Stored Product Pests: Plodia interpunctella, Sitophilus oryzae, Acanthoscelides obtectus and Tribolium castaneum

Summary The purpose of this study is to assess the repellent activity of lemongrass (Cymbopogon citratus) essential oil (EO), grown in Serbia under greenhouse conditions, against four prevalent stored product pests: Plodia interpunctella (larvae), Sitophilus oryzae, Acanthoscelides obtectus and Tribolium castaneum (adults). The lemongrass EO repellency was tested using filter paper in Petri dishes and a Y-tube olfactometer. According to the repellency index (RI), the lemongrass EO repellency was divided into 5 classes. Prior to biotesting, the chemical characterization of lemongrass EO was performed and the following main compounds were detected: myrcene (31.0%), geranial (30.0%), and neral (23.6%). The C. citratus EO considered was found to exhibit the Class III repellent activity against P. interpunctella larvae only at the highest concentration (namely 0.5%). This is the very first report on the C. citratus EO repellent activity against this pest. The lemongrass EO examined showed strong repellency (Class IV) against S. oryzae (0.2% and 0.5% of EO), A. obtectus (0.1% and 0.2%), and T. castaneum (0.05-0.1%). Moreover, higher lemongrass EO concentrations (0.5%) were found to exhibit extreme repellency (Class V) against A. obtectus and T. castaneum. The results obtained were confirmed in the bioassays performed, indicating the great potential of lemongrass EO as a bio-repellent when applied in higher concentrations to all the insects considered, regardless of the exposure period.

Biostimulatory Potential of Microorganisms from Rosemary (Rosmarinus officinalis L.) Rhizospheric Soil

Summary The objective of the present paper was to isolate microorganisms (Pseudomonas sp., Bacillus sp. and Azotobacter sp.) from the rhizospheric soil of rosemary (Rosmarinus officinalis L.) and investigate their biostimulatory (plant growth-promoting – PGP) and biocontrol potential. The bacteria isolated from the rhizosphere of rosemary included 15 bacteria of the genus Pseudomonas, 20 of the genus Bacillus, and 11 of the genus Azotobacter. Based on the morphological characteristics of colonies and cells, representative isolates of each genus were chosen (marked as Pseudomonas sp. P42, P43, P44; for Bacillus isolates B83, B84, B85, B92, B93; and for Azotobacter isolates A15 and A16) for different physiological and biochemical examination. The study included in vitro screening of the bacterial isolates for their PGP and biocontrol properties. Pseudomonas isolates showed the ability to live at low temperature (10ºC) and high pH (9), and to use different sources of carbon. All Pseudomonas isolates produced lipase, siderophore, hydrogen cyanide, and utilized organic and inorganic phosphorus, while only isolate P42 produced amylase, pectinase and cellulase. Only Bacillus isolates could grow at 45 ºC (all Bacillus isolates), pH 5 (isolates B83), and on a medium containing NaCl 5 and 7% (all isolates). Isolates denoted as B83 and B93 produced lipase, amylase, and pectinase. All isolates had the ability to solubilize phosphate, produce siderophores (except B85) and hydrogen cyanide, while only two isolates (B84 and B85) produced IAA. Azotobacter isolates had the optimal growth at 37ºC and minimal growth on a medium with pH 6 and 9. All Azotobacter isolates used all carbohydrates as a source of carbon and produced lipase, amylase, and hydrogen cyanide. The best result in suppressing the growth of pathogenic fungi Fusarium oxysporum was achieved by using isolate B92. Application of isolate B83 led to the greatest growth suppression of Sclerotinium sclerotiorum.

The Development of Organic Agriculture in Serbia and Worldwide

Summary Organic agriculture is a food production system that sustains the health of people, soils and ecosystems with no adverse consequences, combining tradition, innovation and science. The development of such type of agricultural production, from its beginnings to the present day, has encompassed a number of specific stages both in Serbia and worldwide. Accordingly, the purpose of this survey study is to present the developmental course of organic agricultural production in Serbia and worldwide. The paper also summarises the state of organic plant production across different regions of Serbia, arguing that the Serbian organic production has been increasing since the 1990s. Following the political changes in Serbia in 2000, foreign donations, investments and organisations have significantly enhanced the country’s organic production sector as a whole. The largest number of organic producers (1/3) and the largest areas devoted to organic farming are concentrated in Vojvodina.

A Mini Review of the Effects of NSP and Exogenous Enzymes in Broiler Diets on Digestibility and Some Intestinal Functions

Summary NSP (non-starch polysaccharides) are a large group of compounds, which vary greatly in their chemical structure and properties. They are linked with the use of some of the alternative proteins or energy feed ingredients in broiler nutrition. Exogenous enzymes which act on NSP are sometimes in broiler production with the purpose of increasing digestibility of nutrients and consequently increasing broiler performance in production. This paper will attempt to review changes occurring in the digestive tract as a result of the use of feed with NSP soluble and insoluble in water, and the effect of NSPase on them, in terms of how an animal organism is burdened or helped to overcome the problems.

Chlorophyll Fluorescence and Drought Tolerance in a Mapping Population of Durum Wheat

Summary This study was conducted to compare and estimate the genetic variability among durum wheat lines in response to drought according to their grain yields and physiological traits. The use of fluorescence parameters as drought selection criteria for durum wheat was investigated in a population of 249 recombinant inbred lines (RILs) derived from a cross between two cultivars of durum wheat: ‘Svevo’ and ‘Kofa’. The durum wheat RILs considered were analyzed to determine the relationship between their grain yields and chlorophyll fluorescence parameters at the grain filling stage under drought stress (rainfed) and supplemental irrigation (irrigated) conditions during the 2004 and 2005 seasons at the ICARDA center. The results obtained show that the durum wheat line performance was influenced by drought stress, indicating significant differences between the grain yields and fluorescence parameters recorded under drought rainfed (RF) and irrigation (IR) conditions. Significant differences between the experimental groups of durum wheat RILs (P<0.05) were only recorded under drought conditions, with the exception of leaf water potential (Lwp). Under such conditions, nearly all the parameters examined were significantly increased in the high-yielding group (with the exception of the Que parameter), thus revealing the genetic variability of the durum wheat lines considered in response to drought stress. The potential quantum efficiency of photosystem II (Fv/Fm) was found to be positively associated with the grain yield parameter. The mean values of Fv/Fm in both the high- and low-yielding groups significantly dropped under drought stress (0.71 and 0.68, respectively) compared to the Fv/Fm values recorded under irrigated conditions (0.80 and 0.81). Under drought conditions, slopes were highly significant (P<0.001) nearly for all the fluorescence parameters examined (with the exception of CHLSPAD) compared to those recorded under irrigation conditions. It was concluded that chlorophyll content (SPAD), F0, Fm, Fv, Fv/Fm, Lwp, and Que could be used as additional indicators in screening wheat germplasm for drought tolerance.

Role of Proline in Mitigating the Deleterious Effects of Heat Stress in Chillies

Summary Chilli is a spicy crop which belongs to family Solanaceae. As a vegetable crop, it is considered as one of the major cultivated crops in the world seriously affected by the climatic changes, including elevation in temperature. Therefore, in this research various morpho-physiological characteristics of chilli were studied for heat tolerance under the influence of exogenous application of proline. This research was carried out in a growth room of the Institute of Horticultural Sciences, University of Agriculture, Faisalabad, Pakistan. Four chilli genotypes were evaluated under the applied conditions. Seeds were grown in plastic pots. Heat stress (40/32 ºC day and night temperature) was applied 30 days after the emergence. Foliar spray of proline (0, 5 and 10 mM) was applied during heat stress, and after 7 days of stress the plants were harvested. The results revealed that the inhibition of chilli growth by heat stress was successfully mediated by proline application. Morphological attributes such as the number of leaves per plant, root and shoot length, plant fresh and dry weight were reduced in response to heat stress, and physiological attributes such as photosynthetic rate, water use efficiency and chlorophyll contents were also reduced in response to heat stress, except transpiration rate and stomatal conductance, which increased under heat stress and showed recovery by proline application. Exogenous application of proline promoted tolerance against heat stress in chilli genotypes and enhanced growth. All the observed traits exhibited recovery in response to proline stimulus, indicating the role of proline in mitigating the consequences of heat stress. Recovery also depends on genetic capability of various cultivars.