Zea mays originate from warm and tropical region of the world and needs high sum of effective temperature throughout vegetative period. On the Polish market varieties of maize differ in early maturing, provenance and temperature requirements. The foreign varieties react stronger to the sulfonylurea herbicides (nicosulfuron, rimsulfuron, foramsulfuron + jodosulfuron) than Polish maize varieties under unfavorable weather conditions. The trials were conducted in field conditions using 8 maize varieties. The aim of this experiment was evaluation of the influence of sulfonylurea herbicides on foreign and Polish varieties of maize under different weather conditions. The reaction of foreign maize varieties on herbicides was compared with reaction of Polish maize varieties in the years 2001-2002. Four early maturing varieties of maize were testing: AVENUE (FAO 220)-FR, JANNA (FAO 190)-USA, WIARUS (FAO 220)-PL, FIDO (FAO 220)-PL. It was proved that Polish maize varieties showed a higher toleration towards sulfonylurea herbicides. The later maturing varieties KRÓL (FAO 280)-PL, IMAN (FAO 300)-PL, KANZLER (FAO 300)-FR, MAGISTER (FAO 280)-CH responded in a similar way. In 2002 there were no differences in plant development between foreign and Polish maize varieties.

Maize dwarf mosaic virus (MDMV) is a serious and widespread virus pathogen of maize plants. This +ssRNA virus belongs to the Potyvirus genus in the Potyviridae family. Together with sugarcane mosaic virus (SCMV) it causes one of the most important viral diseases on maize crops in the world – maize dwarf mosaic. Both viruses are transmitted in the same non-persistent manner by several aphid species. They induce similar symptoms of leaf mosaic or mottling, stunting and a reduction in plant weight and grain yield. Available MDMV diagnostics include primarily commercialized enzyme-linked immunosorbent assays (ELISA) and reverse transcription-polymerase chain reactions (RT-PCR). Here, laborsaving reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay was optimized for identification of genetically different MDMV isolates. For this purpose, primer sets, MDMVF3/MDMVB3 and MDMVFIP/MDMVBIP amplifying fragments of coat protein coding sequence of MDMV, were used. The specificity of the reaction was verified using three MDMV (-P1, -Sp, -PV0802-DSMZ) and three SCMV (-P1, -PV0368- -DSMZ, -PV1207-DSMZ) isolates. Obtained products were visualised by DNA staining, electrophoretic separation as well as by real-time monitoring of the reaction. The sensitivity of RT-LAMP and conventional RT-PCR reactions was comparable. Both methods could detect virus as low as 550 fg · μl–1 of total RNA. This technique has application value for screening MDMV by phytosanitary services.

The relative relationships “yield – evapotranspiration” were used long time ago. The well known linear relationship yi = 1 – ky (1 – ei), where yi is relative yield, ky – yield response factor and ei – relative evapotranspiration was proposed. It’s usually assumed that ky is constant for a given crop and climatic conditions. It was found, however, that ky for late variety of maize H 708 varied through the study years (1984–1990) in the Plovdiv region (South Bulgaria, altitude 150 m). During the dry years it was significantly higher than in the medium and humid years. The range of ky for maize in this location was 1.12–1.90, the average value being 1.50. The climate in the Sofia region (the ex-perimental field of Chelopechene, altitude 550 m) is comparatively more humid. The two regions approximately outlined the boundaries of the appropriate economical conditions for grain maize pro-duction. The experiments in the Sofia region were carried out in the years 1994–2000. The seven years results for mean variety maize showed that the relationships “yield – evapotranspiration” and, respectively, ky varied at these climatic conditions too. The highest ky value was 1.41 for the driest year (2000) and the lowest value – 1.05 for the most wet years (1995, 1999). The value of ky for av-erage years was 1.21. The yield response factor ky is of more significance when the relative evapotranspiration is less than 0.7–0.8. Thus, the extreme or the average values of ky could be used for the corresponding climatic regions. The relationships between ky and relative yield were estab-lished without considering irrigation.

The experiment on Zea mays L. cv. Landmark (F1) plants was performed in a greenhouse with UV-B (305–315 nm). The pots with plants were divided into four groups: the first and the second groups were grown, respectively, at low (1.0 kJ m-2 d-1) and high (3.0 kJ m-2 d-1) biological effective dose of UV-B radiation. Half of the pots of each group were sprayed with 0.1% solution of Asahi SL (the third and fourth groups). The intensity of photosynthesis and transpiration, chlorophyll fluorescence, the content of UV-absorbing compounds and radical scavenging activity were measured using DPPH after four and six weeks of UV-B radiation. After six weeks of irradiation with a higher UV-B dose both flavonoid content and antioxidant activity increased by 112% and by 44%, respectively, compared to the plants grown at the lower dose. The plants treated with Asahi SL and exposed to the high dose of UV-B had the content of flavonoids 80% higher than the control ones. Asahi SL decreased scavenging activity in both groups of plants by 17% and 32%, respectively, in comparison with the untreated plants. The intensity of net photosynthesis, the transpiration rate and chlorophyll fluorescence parameters (Fv/Fo, ETR, Rfd) did not differ in most of variants.

The research was intended to develop a biocomposite as an alternative biodegradable material, for the production of, e.g., disposable utensils. The author’s tested thermoplastic maize starch, both without additives and with the addition of crumbled fl ax fi ber in the share of 10, 20 and 30 wt%. The plasticizer added was technical glycerin and the samples were produced by a single-screw extruder. The mechanical strength tests were performed, including the impact tensile test and three-point bending fl exural test. Afterwards, the samples were tested for biodegradability under anaerobic conditions. The methane fermentation process was carried in a laboratory bioreactor under thermophilic conditions with constant mixing of the batch. All samples proved to be highly susceptible to biodegradation during the experiment, regardless of the fl ax fi ber share. The biogas potential was about 600 ml·g-1, and the methane concentration in biogas ranged from 66.8 to 69.6%. It was found, that the biocomposites can be almost completely utilized in bioreactors during the biodegradation process. The energy recovery in the decomposition process with the generation of signifi cant amount of methane constitutes an additional benefi t.

Clarifying the genetic background of the drought-tolerance trait is a crucial task that may help to improve plant performance under stress by a genetic engineering approach. Dehydration-responsive element-binding protein (DREB) is a transcription factor family which modulates many stress-responsive genes. In this study, we isolated a DREB homolog gene named ZmDREBtv from Zea mays var. Tevang-1. Using bioinformatic tools, a number of InDels and SNPs in ZmDREBtv sequence different from the reference accession were identified. In addition, based on deduced protein sequence similarity, ZmDREBtv was assigned to transcription factor DREB2 class as featured by a conserved DNA binding domain - AP2. The ZmDREBtv construct under thecontrol of the rd29A promoter was transformed into a drought-sensitive maize plant, K7 line. The transgenic plants were assessed with reference to molecular and phenotypic characteristics related to the drought-tolenrance trait. The results proved that the maize plants carrying ZmDREBtv gene showed enhanced tolerance and better performance to the water-deficit environment at different stages, compared to the wild-type plants.

The mealybug, Phenacoccus solenopsis (Hemiptera: Coccomorpha: Pseudococcidae), is one of the main pests attacking maize plants in Egypt. Field trials were carried out in the maize field to assess the influence of irrigation periods and potassium fertiliser rates on the mealybug ( P. solenopsis) population estimates, vegetative growth, resulting yield, and its components for the maize cultivar (‘Single-Hybrid 168 Yellow’) in the Luxor Governorate, Egypt. Results revealed that unfertilised plants irrigated every seven days had higher pest population densities than other treatments over the two seasons. The fertilised treatments at 114 kg K ₂O∙ha ^–1 that received water every 10 days had the smallest population of P. solenopsis in every season. Data during the two seasons (2021 and 2022) revealed that the maize to which potassium fertiliser was added by 114 kg K ₂O∙ha ^–1 and irrigated every 10 days had vegetative growth (plant height, diameter, and number of green leaves per plant), yield and its components (average ear length, ear weight, number of grains per ear, weight of 1000 grains, and grain yield) significantly increased as compared to those of the plants that were irrigated every 7 days and without adding fertiliser. A higher dose of potassium fertiliser reduces the infestation of P. solenopsis but causes an increment of maize vegetative growth. This affects the final yield. This information aids farmers in comprehending the good agronomic techniques of maize plants to decrease the infestation of mealybugs and increase the yield.

The paper addresses the effect of a compost prepared from tobacco wastes with an admixture of bark and straw on the enzymatic activity and certain chemical properties of a grey-brown podzolic soil amended with that compost.

The study was conducted under the conditions of a pot experiment in which the soil material was collected from the surface horizon of the grey-brown podzolic soil. The effect of the application of the compost was compared with soil without such amendment. The test plant was maize cv. Kosmo 230. Fertilisation of the light soil with the compost studied caused changes in the enzymatic activity of the soil that were related both to the dose of the compost and to the kind of enzyme studied. With increase in the dose of the compost there was an increase in dehydrogenase activity (highest dose) and a significant decrease in the activity of acid phosphatase. Moreover, it was observed that tobacco compost was a significant source that enriched the light soil in organic matter, total nitrogen, and available forms of phosphorus, magnesium and potassium, which was evident in increased yields of maize grown as the test plant.

Significant correlations were also demonstrated between a majority of the biochemical and chemical parameters, which indicates that those parameters characterise well the biological properties of a grey-brown podzolic soil amended with tobacco compost.

The aim of this study was to determine the effect of different zinc and iron concentrations in culture

medium on growth and development of maize and wheat seedlings in terms of their inoculation with bacteria of

Azospirillum genus. Maize and wheat in vitro cultures were inoculated, respectively, by strains of Azospirillum

lipoferum and Azospirillum brasilense strains. The experimental factor was the supplementation of the culture

medium with zinc (25, 200 and 600 mg·kg-1 of the medium) and iron (25, 200 and 600 mg·kg-1 of the medium).

Counts of bacteria from the Azospirillum genus were analysed and plant seedling growth and development as

well as the content of chlorophyll in plant leaf blades were monitored.

Zinc turned out to reduce strongly numbers of bacteria of the Azospirillum genus. Azospirillum brasilense

turned out to be particularly sensitive to elevated levels of this chemical element in the environment. The negative influence of increased quantities of zinc on cereal seedlings became apparent only after the application of

the highest concentrations of this metal in the medium (600 mg·kg-1), while quantities which did not exceed

200 mg·kg-1 exerted a stimulation effect on the mass of maize and wheat seedlings.

Iron added to the culture medium in quantities which did not exceed 200 mg·kg-1 did not reduce numbers of

bacteria of the Azospirillum genus; on the contrary, they stimulated their growth. However, at higher concentrations, this metal turned out to exert a strong negative impact on the chlorophyll content in leaf blades as well as

on the mass of maize and wheat seedlings.

The inoculation with bacteria of the Azospirillum genus exerted a positive influence on the mass increase of

maize and wheat seedlings and increased chlorophyll concentrations in leaf blades. At the same time, it contributed significantly to limiting or even levelling out the toxic impact of zinc and iron during the initial phases of

plant growth and development.

This paper presents the results of fractionation of particulate and soluble organic matter in a mixture of maize silage and cattle manure (49:51% volatile solids) that was used as a feedstock for anaerobic digestion. The extended Weender’s analysis was adapted to measure raw protein, raw lipids, fraction of carbohydrates (including starch, cellulose, hemicelluloses) and lignin. The content of individual fractions in composite, Xc (as kg COD kg-1 COD) was: 0.111 proteins, 0.048 lipids, 0.500 carbohydrates and 0.341 inerts. The biodegradability of Xc was 68%. Based on material balance, the carbon concentration in Xc was 0.0326 kmol C kg-1 COD, whereas nitrogen concentration 0.0018 kmol N kg-1 COD. The estimated pH of the feedstock based on acid-base equilibrium corresponded to the actual value (pH 7.14).

The aim of this study was to implement ADM1xp model to simulate behavior of anaerobic co-digestion of maize silage and cattle manure. The accuracy of ADM1xp has been assessed against experimental data of anaerobic digestion, performed at OLR = 2.1 gVS dm-3·d-1 and HRT = 45d. Due to the high number of parameters in ADM1xp, it was necessary to develop a customized procedure limiting the range of parameters to be estimated. The best fitting of experimental to simulated data was obtained after verification of 9 among 105 stoichiometric and kinetic parameters. The values of objective function (Jc) ranged between 0.003 (for valerate) and 211 (for biogas production).

Some aspects of the epidemiology of Maize streak virus (MSV) genus Mastrevirus concerning virus incidence, vector populations and some environmental factors were investigated in field experiments conducted over a three year period (2000–2002) at Samaru, northern Nigeria. Significant positive correlations were obtained between number of leafhoppers caught and MSV incidence and age of plant at infection and also with temperature. Also significant negative correlations were obtained between MSV incidence and mean relative humidity; between number of leafhoppers and age of plants and with mean rainfall. Leafhopper vectors caught included Cicadulina arachidis China, C. mbila Naude, C. triangula Ruppel and C. similis China, in order of abundance. Leafhopper incidence was highest in the months of September and October.

In this paper we present the first occurrence of the Diabrotica virgifera Le Conte in Poland and the measures taken against this pest. The specimens of western corn rootworm were found in South-Eastern Poland (Podkarpackie voivodeship) at the end of August and in September of 2005.

Biological control of plant diseases is strongly emerging as an effective alternative to the use of chemical pesticides and fungicides. Stress tolerance is an important attribute in the selection of bacteria for the development of microbial inoculants. Fourteen salt-tolerant bacteria showing different morphological features isolated from the rhizosphere of maize were evaluated for different plant growth-promoting activities. All isolates showed auxin production ranging from 5 to 24 μg ⋅ ml–1 after 48 h incubation in tryptophan supplemented media. Phosphate solubilization ranged from 15 to 419 μg ⋅ ml–1. 1-aminocycloproprane- 1-carboxylate (ACC) deaminase activity was shown by 6 isolates, ammonia production by 9 isolates, siderophore production by 8 isolates while HCN production by 4 isolates. Four bacterial isolates with all plant growth-promoting properties also showed strong antagonistic activities against Fusarium oxysporum, F. verticillioides, Curvularia lunata and Alternaria alternata and abiotic stress tolerance against salinity, temperature, pH and calcium salts. Two selected bacterial isolates significantly enhanced the growth of pea and maize test plants under greenhouse conditions. The bacterial isolate M1B2, which showed the highest growth promotion of test plants, was identified as Bacillus sp. based on phenotypic and 16S rDNA gene sequencing. The results indicated that Bacillus sp. M1B2 is a potential candidate for the development of microbial inoculants in stressful environments.

Plant viruses create many changes in the morphology of the plant cell once the infection process has begun. This paper describes and compares the ultrastructural changes induced in maize cells by two isolates of Maize dwarfmosaic virus (MDMV), Spanish (MDMV-Sp) and Polish (MDMV-P), and one isolate of Sugarcane mosaic virus (SCMV) at 10 and 42 days post-inoculation: the concentration and arrangement of virus particles, inclusion bodies associated with infection, and other cytological alterations. The most important difference between maize cells infected with MDMV isolates and with SCMV-P1 was in the form of cytoplasmic cylindrical inclusions. In cells infected with MDMV only typical inclusions such as pinwheels and scrolls were observed, but laminar aggregates were also present in SCMV-infected cells. No virus particles were found in plant cell organelles. Specific virion arrangements occurred in cells infected with MDMV-Sp and SCMV. The most interesting new finding was of specific amorphous inclusions in the cytoplasm of MDMV-Sp-infected cells, which clearly differentiated the two MDMV isolates studied.

Salinity is one of the most significant constraints to crop production in dry parts of the world. This research emphasizes the beneficial effects of plant growth-promoting rhizobacterial isolates (PGPR) on the physiological responses of maize and wheat in a saline (NaCl) environment. Soil samples for the study were collected from a maize field in Baddi, Himachal Pradesh, India. Isolated bacterial strains were screened for salt (NaCl) tolerance and plant growth-promoting characters (i.e., indole acetic acid (IAA) production, siderophore production, amino cyclopropane-1-carboxylic acid (ACC) deaminase activity, hydrogen cyanide (HCN) production, and mineral phosphate solubilization). Screened bacterial isolates were further tested in pot experiments to examine their effects on wheat and maize growth. The treatments included five levels of bacterial inoculation (P0: control, P1: ACC deaminase positive + siderophore producer + NaCl tolerant bacteria, P2: mineral phosphate solubilizer + HCN producer + NaCl tolerant bacteria, P3: IAA producer + ACC deaminase positive + NaCl tolerant bacteria, P4: bacterial consortium, P5: Phosphomax commercial biofertilizer) and salt stress at 6 dS/m. Research findings found that exposure to a bacterial consortium led to the highest growth parameter in maize, including shoot length, root length, shoot and root dry weight followed by P2, P3, and P5 treatments at 6 dS/m salinity levels. However, P2 showed the best results for wheat at the same salinity levels, followed by P3, P4 and P5 treatments. P1 treatment did not show a significant result compared to control at 6dS/m salt level for both crops. The maximum proline content in maize and wheat was observed in P4 (23.28 μmol · g−1) and P2 (15.52 μmol · g−1) treatments, respectively, followed by P5 with Phosphomax biofertilizer. Therefore, the study proposed the application of growth-promoting bacterial isolates as efficient biofertilizers in the Baddi region of Himachal Pradesh, India.

The purpose of this study has been to determine the effect of fertilisation with urea-ammonium nitrate (UAN) solution enriched with P, Mg or S on the content of macronutrients in the grain and straw of maize. The following fertilisers were tested in the field experiment: ammonium nitrate, urea, UAN – 32% N; RSM+S – 26% N + 3% S; RSM+P(Medium) – 26% N and 4.80% P; RSM+P(Starter) – 21% N and 7.86% P; UAN + Mg – 20% N + 4% Mg. In each year of the experiment, significant differentiation in the contents of P, K, Ca, Mg and S in maize grain and straw was observed, depending on the applied nitrogen fertilisation. However, considering the average values from each treatment achieved over the three years, it was demonstrated that the fertilisation significantly changed only the content of P and S in grain and K and Ca in straw of maize. The removal of nutrients was the highest in the second year of the research and amounted in kg∙ha ^–1: P – about 100, K – about 350, Ca – about 80, Mg – about 35 and S – about 31, which in turn were differentiated over the years of the experiment in the three years. The removal of P, K, Mg and S also significantly depended on fertilisation. Significant differences, however, most often concerned the control treatment relative to the fertilised ones. The contribution of grain to the accumulation of nutrients also varied significantly in the three years of the experiment. Significantly the lowest share of grain in terms of P and S accumulation was noted in maize grown without N fertilisation.

The fertilizing value of rye, potato and molasses decoctions was evaluated in a microplot experiment, in which maize and turnip were used as testing plants. Based on the analysis of chemical composition of decoctions it was found that these decoctions used as fertilizing material were unbalanced with respect to their N, Pand K contents. The potato decoction is characterized by the most favourable N:K ratio from the point of view of the nutritional requirements of plants. The rye decoction contains too little potassium and that from molasses - too much of this element in relation to N content. The use of the molasses decoction in fertilizing is possible after its correction with phosphorus. The rye decoction requires correction with potassium for appropriate use in fertilization. In addition, application of the decoctions studied caused an increase in the organic C and total N contents in soil and improvements in the sorption properties of soil. The molasses decoction caused a decrease in the available forms of P in soil. The decoctions applied in experiments considerably increased yields and nutrient content in plants studied, both in the direct and after- effect.

The future of food security in Africa is being severely threatened due to an exponential increase in population, which is almost three times the increase of food production. Maize production is constrained by stem borers which cause significant yield losses. Yield losses can be further compounded by higher temperatures due to climate changes, which are expected to increase the population of maize stem borers. While several methods have been employed in stem borer management, there is still significant damage caused by maize stem borers. This necessitates better control methods including the adoption of recent biotechnological advancement in RNA interference (RNAi) technology. This review highlights evidence of an increase in the stem borer population as well as the foreseen decline in maize production worldwide due to the effects of climatic changes. Furthermore, we have drawn attention to improved methods that have been used to control stem borers in maize production as well as a reluctant acceptance of traditional biotechnology in Africa. Finally, we suggest the application of alternative RNA interference techniques to breed maize for efficient pest control in order to achieve food security, improve nutrition and promote sustainable maize production.

The evaluation of effect of the grass and broadleaf weed control of different mixture rates of mesotrione plus pethoxamid and terbuthylazine applied postemergence in maize was conducted in the field experiments during the 2005 and 2006 growing seasons. There was no phytotoxicity observed on maize after herbicide treatments. Herbicide mixture provided higher levels of Echinochloa crus-galii (L.) Beauv. control than mesotrione used alone. In the postemergence trials, the broadleaf weeds, except Chenopodium album L., were not well controlled by the mesotrione-alone treatment. The addition of pethoxamid plus terbuthylazine to mesotrione significantly improved the control of broadleaf weeds. Mesotrione and mesotrione plus pethoxamid and terbuthylazine treated plots were always among the highest yielding as compared to untreated plots. Any reductions in cob and grain yield were always associated with high weed fresh matter yields indicating that it was the weed competition that led to reduced yield and not herbicide phytotoxicity.

The aim of this study was to investigate the influence of residual glycerine (5 and 10% w/w) from the biodiesel industry, used as a co-substrate, on biogas production from maize silage. The experiments were conducted in a laboratory-scale, single-stage anaerobic digester at 39ºC and hydraulic retention time (HRT) of 60 d. Addition of 5% residual glycerine caused organic load rate (OLR) to increase to 1.82 compared with 1.31 g organic dry matter (ODM) L-1d-1 for maize silage alone. The specific biogas production rate and biogas yield were 1.34 L L-1d-1 and 0.71 L g ODM-1 respectively, i.e. 86% and 30% higher than for maize alone. Increasing the residual glycerine content to 10% increased OLR (2.01 g ODM L-1d-1), but clearly decreased the specific biogas production rate and biogas yield to 0.50 L L-1d-1 and 0.13 L g ODM-1 respectively. This suggested that 10% glycerine content inhibited methanogenic bacteria and organics conversion into biogas. As a result, there was accumulation of propionic and valeric acids throughout the experiment.

We measured the total chlorophyll (Chl a+b) content in seedling leaves of fifteen maize cultivars infested by two studied aphid species (oligophagous Rhopalosiphum padi L., monophagous Sitobion avenae F.) 7 and 14 days after the beginning of infestation, using a SPAD-502 chlorophyll meter. Chlorophyll loss was more severe in R. padi-infested than in S. avenae-infested plants. Chlorophyll depletion was greater after long-term (14 days) than after short-term aphid infestation in the investigated host systems. Seedlings of Złota Karłowa and Tasty Sweet were more damaged by aphid feeding; Ambrozja and Płomyk plants were less damaged by aphid feeding.

Application of 1-naphthaleneacetic acid (NAA) or 1-aminocyclopropane-1-carboxilic acid (ACC) to maize roots growing in hydroponic solution inhibited root elongation, and increased radial growth, but the responses to those treatments differed in degree. Auxin was more effective than ACC as an elongation inhibitor and root swelling promoter. Whereas NAA fully inhibited elongation and maintained swelling over 48 h, ACC inhibited elongation partially (50%) and only promoted swelling for 24 h. It is well-known that auxin, like ACC, promotes ethylene production, but similar levels of ethylene production reached by means of NAA or ACC treatments did not elicit the same response, the response being always stronger to NAA than to ACC. These results suggest that the effect of auxin on root growth is not mediated by ethylene. Elongation and swelling of roots appear to be inversely related: usually a reduction in elongation was accompanied by corresponding swelling. However, these two processes showed different sensitivities to growth regulators. After 24 h treatment with 0.5 μM NAA or 5 μM ACC, root elongation was inhibited by 90% and 53% respectively, but the same treatments promoted swelling by 187% and 140% respectively. Furthermore, 1 μM ACC was shown to promote inhibition of root elongation without affecting swelling. The ethylene antagonist STS (silver thiosulfate) did not affect elongation in control or NAAtreated roots, but increased ethylene production and swelling. These results indicate that longitudinal and radial expansion could be independently controlled.