Marker assisted breeding for the maize nutritional enhancement

Combined with traditional selection techniques, marker assisted breeding aimed at the maize nutritional enhancement has been established at the Maize Research Institute Zemun Polje. Over the years, commercial maize inbred lines of standard quality have been converted to quality protein maize (QPM), as well as beta-carotene rich (BCR) maize, adapted to temperate regions. These newly developed lines were used for developing high-yielding maize hybrids with improved nutritional benefit adapted to temperate regions. Simple sequence repeats (SSR) were efficiently used for direct selection of target gene (foreground selection) and for fast recovery of recurrent parent's genome (background selection). As gene-specific markers in foreground selection, phi057 and umc1066 were used for QPM lines, while crtRB1-3TE marker was used for BCR lines. Background selection was performed with SSR markers evenly distributed throughout the genome. The recovery of the recipient genome in our best lines varied from 93% to 99% for QPM and from 90% to 99% for BCR. Biochemical evaluation of resulting improved hybrids showed increase of relevant nutritional parameters. Tryptophan content and tryptophan to protein ratio, an indicator of improved nutritional protein quality, were significantly higher (p<0.05) in QPM hybrids compared to standard maize. Also, tryptophan was above 0.075%, which corresponds to the QPM threshold value. Similarly, beta-carotene content in BCR hybrids was significantly higher (p<0.01) in comparison with the standard hybrids (increase up to 78.11%). Furthermore, starch and lipid contents were significantly higher (p<0.01) in improved hybrids. These results confirmed the success of the marker assisted conversion process, resulting in hybrids with improved nutritional value for use in feed industry

Genotypic variability of grain number and grain mass per spike in bread wheat cultivars

U radu je proučena varijabilnost komponenti prinosa (broj zrna po klasu i masa zrna po klasu) kod deset sorti ozime pšenice (Aleksandra, Planeta, Ana Morava, Toplica, KG-56S, Studenica, Kruna, Takovčanka, Vizija i Pobeda). Ogledi su izvedeni u Centru za strna žita Kragujevac tokom dve vegetacione sezone, po modelu retke setve (dužina reda 1m, sa razmakom 0,20 m između redova i 0,10 m između biljaka u redu), kako bi biljke ispoljile svoj genetički potencijal za ispitivane komponente prinosa. Analiza primarnog klasa urađena je u punoj fiziološkoj fazi zrelosti na uzorku od 60 biljaka (20 biljaka po ponavljanju). Ustanovljene su statistički visoko značajne razlike kod obe ispitivane komponente prinosa za genotip (F=25,84** za broj zrna/klasu; F=7,67** za masu zrna/klasu), godinu (F=255,98**; F=85,86**), i interakciju genotip×godina (F=15,45**; F=8,79**). Varijabilnost ispitivanih osobina bila je visoka, u proseku za obe godine. Koeficijent varijacije za broj zrna po klasu je iznosio 16,6%, a za masu zrna po klasu 19,3%). Najveći broj zrna po klasu, u proseku, imale su sorte Kruna (81,3) i Pobeda (77,0), a prosečna vrednost za ovu osobinu iznosila je 68 zrna po klasu. Prosečna vrednost mase zrna po klasu bila je 2,8 g, a najveću vrednost za ovo svojstvo ostvarile su sorte Vizija i Pobeda (3,1 g). Istraživanjima je ustanovljeno da su ispitivane komponente prinosa veoma varijabilne i da na njihovo ispoljavanje značajno utiču genetički i ekoloških faktori.In the paper, the variability of yield components (number of grains per spike and weight of grains per spike) was studied in ten varieties of winter wheat (Aleksandra, Planeta, Ana Morava, Toplica, KG-56S, Studenica, Kruna, Takovčanka, Vizija and Pobeda). Experiments were carried out at the Center for Small Grains in Kragujevac during two growing seasons, according to the sparse sowing model (row length 1m, with a distance of 0.20 m between rows and 0.10 m between plants in a row), so that the plants could express their genetic potential for the tested yield components. The analysis of primary spike was performed in the full physiological stage of maturity on a sample of 60 plants (20 plants per replication). Statistically highly significant differences were found in both examined components of yield for genotype (F=25.84** for number of grains per spike; F=7.67** for weight of grains per spike), year (F=255.98**; F=85.86**), and genotype×year interaction (F=15.45**; F=8.79**). The variability of the examined traits was high, on average for both years. The coefficient of variation for the number of grains per spike was 16.6%, and for the weight of grains per ear 19.3%). The cultivars Kruna (81.3) and Pobeda (77.0) had the highest number of grains per spike, and the average value for this trait was 68 grains per spike. The average value of grain mass per spike was 2.8 g, and the highest value for this property was achieved by the Vizija and Pobeda cultivars (3.1 g). Research has established that the tested yield components are highly variable and that their expression is significantly influenced by genetic and environmental factors

Mineral composition of the common winter wheat grain grown in different tillage and nitrogen levels

The content of mineral elements is a fundamental component of wheat grain quality and varies depending on applied cultural practices. The aim of the study is to examine the impact of wheat production methods on the composition of mineral elements in the grain. The field experiment was conducted in completely randomized blocks on luvic chernozem soil of the Faculty of Agriculture "Radmilovac".The variety of common soft wheat Ilina (Triticum aestivum ssp. vulgare), was cultivated in three tillage systems - conventional, mulch and notillage. In addition to basic cultivation fertilization treatment with NPK fertilizers in the autumn, two different amounts of N in top dressing (60 and 120 kg/ha N), were added in spring. Standard measures in wheat production were applied and the harvest was carried out at the end of June. Concentrations of 18 eighteen elements (As, Al, Ba, Ca, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Ni, S, Sr, P, V and Zn) in wheat grain samples were determined by means of inductively coupled plasma with optical emission spectrometry (ICP–OES). The results indicated that the concentrations of the studied elements in the wheat grain were significantly affected by the tillage systems and fertilization rates (p < 0.001), as well as the interaction of these two factors. The lowest content of the examined macroelements (K=3052mg/kg and P=3617 mg/kg), as well as the highest concentration of microelements, such as (Cu=5.104 mg/kg and Ni=0.517 mg/kg), was observed in the grain produced in the conventional tillage. The highest concentrations of Fe 48.28 mg/kg, Ba 2.991 mg/kg, and Mn 24.4 mg/kg were detected in the grain treated with 60 kg/ha N. Reduced tillage and reduced nitrogen fertilization had significantly higher positive effect on the concentration of nutritionally important minerals (Ca, Fe, K, Mg, P and Zn) in respect to the conventional tillage with higher levels of nitrogen. Results indicate that in semi-arid climate reduced soil tillage could serve as an important part of sustainable cropping system to facilitate food security

Diurnal variability in chlorophyll fluorescence of soybean under field conditions: Implications for heat stress response

Monitoring variations in photosynthetic efficiency throughout the day allows the variability of plant stress responses to be studied, helping to improve precision breeding and management. Chlorophyll a fluorescence (ChlF) was measured twice in the field during the flowering phase in nine soybean genotypes. The measurements were taken in the morning, which corresponds to optimal environmental conditions, and at midday, which corresponds to elevated temperatures that normally cause stress in the plants. Treatment, genotype and their interaction were highly significant sources of variability (p < 0.001) for all ChlF parameters tested. Genotypes differed significantly (p < 0.05) in their stress response, expressed as a percentage change in values from morning to midday. The largest average diurnal change was observed for the performance index on an absorption basis (PIabs, 63.8%) and the smallest for the electron transport flux per active reaction centre (ET0/RC, 6.5%). According to the results, heat stress affected both the efficiency with which the absorbed light is used in photochemistry (Fv/Fm) and the electron transport beyond the primary quinone acceptor (ET0/TR0). This was confirmed by the results of the energy fluxes per reaction centre, where ABS/RC, TR0/RC and DI0/RC increased as a result of the high midday temperatures, while ET0/RC decreased. This indicates that although the apparent energy input per active reaction centre increased, less energy was directed into productive photochemistry – that is, the overall photochemical efficiency was reduced. The average PIabs decrease confirms that the overall photosynthetic performance of PSII was impaired and less efficient at high temperatures, indicating a reduced capacity for photochemical conversion. Among the genotypes, photosynthetic efficiency was least impaired in line OS-922 and most impaired in OS-1522. The photosynthetic apparatus of line OS-1322 proved to be very stable under elevated heat, with PIabs remaining almost unchanged as a measure of photosynthetic performance compared to optimal conditions

Mycotoxins content in organic and conventional cereal grains and their products

Despite numerous studies comparing the mycotoxin content between organic and conventional cereal grains, there are still controversies and doubts. The assumption is that there is a greater amount of mycotoxins in organic cereal grains due to the impossibility of using classic fungicides to protect against phytopathogenic fungi. Consumer awareness about the health risks from mycotoxins is still relatively low. Using a review of the relevant scientific literature, an analysis of the frequency and concentration of the most common pathogenic fungi (Fusarium, Claviceps, Penicillium, and Aspergillus species) in organic and conventional cereal grains and products was performed. Contamination of cereals with mycotoxins is influenced by a number of factors, such as climatic conditions during the growing and harvest season, variety choice, agrotechnical measures (tillage, fertilization, rotation design/pre-crop, crop protection), as well as postharvest management (drying and cleaning of harvested grains and storage conditions). Contamination with mycotoxins produced by Fusarium sp. decreased between the 1990s and 2020. Significant effects of production system on the incidence and/or concentrations of T-2/HT-2 toxins, zearalenone, enniatin, beauvericin, ochratoxin A (OTA), and aflatoxins were observed. Also, 50% higher concentrations of deoxynivalenol were observed in conventional than organic cereal grains and products. It can be concluded that no significant difference was found in the content of mycotoxins between organic and conventional cereals and their products. Contamination levels are similar in organic and conventional cereals

Mining maize gene bank diversity for desirable alleles

Modern agriculture combats a dual challenge-meeting societal demands for eco-friendly practices and diverse, healthier products and sustaining production in the face of climate change. This combination of factors raises unprecedented questions about how to identify and improve suitable plant materials that can be delivered to farmers and other end users. In this context, understanding the role of seed gene banks is crucial. They serve multiple functions - collecting new plant materials, conserving them under controlled environments, testing seed health, conducting research to characterise and evaluate these materials for breeding important traits and resilience against abiotic and biotic stresses, and distributing them to plant breeders, researchers, farmers, and the food industry. The vast array of traits found in cereal genetic resources maintained in ex situ collections - gene banks, along with their adaptability - is vital for enhancing the resilience of agricultural production systems and advancing innovative, efficient agro-food systems and other bio-based value chains. Thus, they represent a key form of natural capital necessary for stability and adaptability in agriculture and for fostering a sustainable bio-economy. Despite the importance of genetic diversity in plant breeding, most cereal ex situ collections are underutilised, with less than 5% actively used. Despite efforts over the past few decades to expand cereal ex situ collections globally, their size complicates the maintenance and evaluation of the genetic diversity they encompass. Many accessions lack sufficient evaluation data, hindering effective responses to user needs. Typically, only minimal passport data is available, and detailed information on unique traits is often missing. Significant gaps in documentation and characterisation hinder breeding programs. Only 64% of accessions are morphologically characterised, 51% agronomically, 14% biochemically, and about 22% for biotic traits. Hence, comprehensive characterisation is essential for maximising the value of cereal genetic resources and helping users select appropriate germplasm

The effect of maize landraces and testers on the number of leaves above the ear in test cross hybrids

The variation of the number of leaves above the ear in maize test cross hybrids was analyzed to identify superior combinations for this trait. The experiment involved crossing 31 maize landraces with three testers (L217, L73B013, and L255/75-5), representing different heterotic groups (Iowa Dent, BSSS and Lancaster). The general mean for the number of leaves above the ear was 6.18 leaves. The analysis of variance revealed that all sources of variation, including the environment, tester, landrace, and their interactions, were highly significant (p≤0.01), except for the triple interaction (p=0.964). The coefficient of variation was 6.00%, indicating low within-group variability. Maize landrace AN1569, across all testers, exhibited the highest number of leaves (6.72), suggesting its superior general combining ability for this trait. Other landraces, such as AN877, AN288, and AN197, also showed high values, predominantly belonging to dent maize types from late maturity groups. In contrast, the maize landrace AN1890, in test cross hybrids, produced the lowest number of leaves above the ear (5.76). Tester L73B013 contributed to hybrids with the highest number of leaves above the ear (6.31), compared to L217 and L255/75-5, which were statistically similar to each other. A positive correlation (r=0.782) was observed between the number of leaves above the ear in landraces per se and their general combining ability, emphasizing the additive genetic effects in the inheritance of this trait. These results emphasize the importance of specific landraces and testers in breeding programs aimed at improving the number of leaves above the ear, with potential implications for yield and adaptability

Evaluating of Nutritional Traits in Maize Inbred Lines

Modern maize hybrids, which are primarily bred for high yields, often do not meet human nutritional requirements. Inbred lines (ILs), which serves as parental components in hybrid development, represent a valuable reservoir of nutritional traits. Bioactive compounds naturally present in maize—carotenoids and tocols (including tocopherols (T) and tocotrienols (T3))—possess antioxidative properties hat have a positive effect on human health. In this study, 85 ILs from the Maize Research Institute "Zemun Polje" gene bank were evaluated and compared to five commercial lines (SLs). The content of carotenoids (including lutein + zeaxanthin, β-carotene, and β-cryptoxanthin) and tocols (comprising α-T, β+γ-T, δ-T, α-T3, β+γ-T3, and δ-T3) was quantified using high-performance liquid chromatography with diode array and fluorescence detection (HPLC-DAD/FLD). The content of quantified phytochemicals was expressed as the mean value of three independent injections, and the obtained results were subjected to one-way ANOVA. The carotenoid content in ILs ranged from 10.80 to 40.13 μg/g dry weight (dw), whereas SLs showed a range of 27.35 to 44.74 μg/g dw. The tocols content in ILs varied between 44.71 and 129.05 μg/g dw, while SLs had values ranging from 39.26 to 82.48 μg/g dw. Among all lines tested, IL-29 exhibited the highest total carotenoid content (40.13 μg/g dw), while IL-13 displayed the highest βcarotene content (3.16 μg/g dw). Similarly, IL-66 had the highest total tocols content (129.05 μg/g dw), and IL-34 recorded the highest α-tocopherol content (18.11 μg/g dw). These results underscore the gene bank's role as a rich source of nutritional diversity. Notably, IL-13 and IL-34 stand out as promising candidates for breeding maize hybrids with enhanced β-carotene and α-tocopherol content, respectively. However, possible incomplete gene bank's germplasm coverage could be overcome by expanding germplasm screening and assessing broader agronomic impacts to ensure stable, effective nutrient improvements in maize