The paper presents the study of bread wheat’s chlorophyll content and grain yield traits under changing environmental conditions — optimal water supply and simulated water-deficit conditions. Selecting 15 wheat cultivars from different regions (Russia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkey, and CIMMYT) based on economically valuable characteristics became the specimens for the presented study that evaluated the SPAD indicators in correlation with the grain yield in bread wheat and determined the vital role of genotypes, environments, and genotype by environment interaction effects. The relationship between chlorophyll content and yield parameters under different growing conditions was also well-defined. The results revealed that ecosystems had more influence on the chlorophyll content than the wheat genotypes. Several wheat cultivars with soil moisture tolerance have gained identification, along with the correlation coefficient between chlorophyll content and grain yield under varied environmental conditions of water supply. The study validated the role of genotypes and environments in the manifestation of responses to stress conditions.

Keywords: Bread wheat (Triticum aestivum L.), optimum water supply, water-deficit condition, chlorophyll content index, grain yield, correlation coefficient

Key findings: Climate variability for two years made it possible to determine the wheat genotypes’ potential for resistance to abiotic stress conditions. In the studied cultivars, under the relatively dry season, the chlorophyll content was about the readings of SPAD 250 at 10 units less than in the crop season with high humidity at the early wheat phase. An external factor strongly influenced the chlorophyll content, while the specificity of the cultivars was only 12.7%. The other factors, such as, the volume and pubescence of the leaf and the soil conditions, showed an impact of 15.3%.

The article presents the results of a study in the agrocenosis of soft winter wheat to determine the effects of pre-sowing and early spring application of various forms and combinations of nitrogen, phosphorus, and potash fertilizers when growing it in the leached chernozem of the Western Ciscaucasia. The soil is characteristic of a satisfactory state of the structure, density: 1.26–1.42 g/cm³; active acidity (pH): 6.29– 6.58 pH; exchangeable (pH): 5.11–5.25 units; hydrolytic: 1.94–3.05 meq/100 g; the amount of absorbed bases: 27.5–31.2 meq/100 g; cation exchange capacity: 30.6–33.1 meq. /100 g; the soil saturation degree with bases: 90.2%–94.3%; and humus content: 2.93%. Fertilizers improve the nutrient regime of the soil. The average supply level with mineral nitrogen, high and mobile phosphorus, and very high mobile potassium has been well-defined. It could lead to an increase in grain when applying N120P30K60 – 1.28 t/ha (or 24.1%), N120P90K20 – 1.47 t/ha (or 27.8%), and N120P90K60 – 1.53 t/ha (or 28.8%). The grain yield of soft winter wheat was 6.58, 6.77, and 6.83 t/ha, respectively. The protein content in the grain varied from 13.2% to 14.3%. The collection of protein per hectare was 870.5, 948.5, and 958.3 kg/ha for the treatments N120P30K60, N120P90K20, and N120P90K60, respectively. The protein in the control was equal to 554.9 kg/ha. Dispersion analysis of the study results showed the share of the contribution of the factor “combination of fertilizers” was 75.95%. Similarly, the data analysis of the conditions of the agricultural year and combinations of mineral fertilizers has a smaller share – 19.24%. With the introduction of N120P30K60 and N120P90K20, the payback of mineral fertilizers by increasing the yield of soft winter wheat grain is the largest – 6.10 and 6.39 kg/kg a.i. NPK, respectively.

Keywords: Soft winter wheat, leached chernozem, Western Ciscaucasia, mineral fertilizers, nitrogen, grain yield

Key findings: Mineral fertilizers improved the feeding system by soft winter wheat grown on chernozem soil in Western Ciscaucasia. The payback of mineral fertilizers by winter wheat with an application of N120P30K60 and N120P90K20 was the highest (6.10 and 6.39 kg/kg a.i. NPK), respectively.

Wheat yellow (stripe) rust (Puccinia striiformis f. sp. tritici) is a dominant type of winter wheat disease. Developing new, highly productive varieties with increased immunological indicators helps to minimize the threat of rust spread. The progressive study searched the sources of resistance to the Pst populations and determined the effectiveness of Yr genes in Southeast Kazakhstan. Immunological studies ensued during 2018–2022 at the Kazakh Research Institute of Agriculture and Plant growing, Almaty, Kazakhstan. Wheat’s 23 isogenic lines and 193 winter wheat genotypes attained evaluation for their reactions against an artificially infectious background of infection mixed with Pst pathotypes. Determining the intensity of virulence, the effectiveness of Yr genes, and the resistance of genotypes to the Pst population transpired in the said region. During the vegetation period, based on weather conditions, the accumulated flow of the source, and the period of infection, wheat genotypes responded differently to the rust disease manifestation. The wheat genotypes found resistant to P. striiformis and promising for selection with immunity reached nomination. Their practical use centered on increasing the immunological potential of the new winter wheat cultivars for creation and further reducing the large-scale use of fungicides and the negative environmental consequences.

Keywords: Wheat (Triticum aestivum L.) genotypes, isogenic lines, P. striiformis, wheat yellow rust, wheat stripe rust, rust resistance, immunity, conventional breeding

Key findings: The winter wheat (Triticum aestivum L.) genotypes resistant to P. striiformis and promising for selection with immunity were notable. Their practical use centered on increasing the immunological potential of new wheat cultivars for development and reducing the large-scale use of fungicides and the negative environmental consequences.

Rock melon (Cucumis melo L. var. Cantalupensis) is a commercial-type melon with a wide distribution worldwide. Rock melons with larger fruit sizes are more in demand in restaurants, the food processing industry, and large families. In breeding for larger fruits, the increased genetic variability through introgression and recombination is the main factor; then, it can continue to purify before becoming a parental line. The presented study sought to recognize the variability of the open-pollinated population and their performance after selfing. The experiment ran from September 2021 to July 2022 at the Field Experimental Station, Politeknik Negeri Lampung, Indonesia. The experiment consisted of two sub-experiments carried out without experimental design. There was wide variability in both quantitative and qualitative variables in the open-pollinated populations, except fruit flesh color, weight, and sugar content. Population after selfing (S1 population) had more uniform qualitative traits. All the fruits sampled were medium elliptic with netted rinds followed by two-color variants (greenish yellow and green). Also, narrow variability occurred for the traits, fruit diameter, weight, and sugar content, followed by low heritability for the quantitative traits.

Keywords: Genetic variability, heritability, introgression and recombination, melon (Cucumis melo L.), open-pollinated population, quantitative and qualitative traits, selfed (S1 population)

Key findings: In F₂ segregating populations, a wide diversity of quantitative and qualitative traits proved that intercross ably maintained variability as per Handy-Weinberg equilibrium theory. Besides, the high heritability was evident for fruit shape and color traits after selfing, particularly for elongated and green color traits. They seemed like simple allelic traits.

Appropriate parental selection is the breeder’s main concern to exploit the highest genetic diversity and generate superior genotypes for subsequent breeding programs. Hence, the presented investigation proceeded to evaluate 353 breeding lines of rice at three breeding zones (Rajshahi, Cumilla, and Gazipur) in Bangladesh in replicated yield trials during the Boro season of 2018–2019 to identify the best genotypes and utilize them as parental materials. Data recorded on 12 yield-related traits helped to determine the best breeding lines with higher predicted breeding values. The first five principal components (PC1, PC2, PC3, PC4, and PC5) represented more than 70% (75.1%) contribution to the variability of the data. Three hundred fifty-three rice genotypes incurred distribution into five clusters over three environments. Clusters I, II, III, IV, and V comprised 66, 51, 83, 79, and 74 genotypes, respectively. Based on estimated breeding values (EBVs), IR107971-B-B RGA-B RGA-202 showed the highest value (0.395), followed by IR 108000-B-B-B-B-13 (0.329), IR 103309-B-B RGA-B RGA-194 (0.321), IR 107982-B-41-1-2-1 (0.291), IRRI 174 (0.264), and IR 107976-B-B RGA-B RGA-254 (0.234). The lowest EBV (0.022) appeared in IR103309-B-B RGA-B RGA-204 among the top 20 genotypes. Both IR 103309-B-B RGA-B RGA-194 (0.321) and IR 107982-B-41-1-2-1 (0.291) could benefit as parents for further breeding programs having higher EBVs and higher genetic diversity.

Keywords: Rice, cluster analysis, estimated breeding values, parental materials

Key findings: EBVs and cluster analysis can assist breeders in selecting the best parents for the next breeding program. The top 20 genotypes based on EBVs with the highest genetic diversity may serve as parents to produce desired plant progenies crucial for the ever-growing populations. More specifically, IR 103309-B-B RGA-B RGA-194 and IR 107982-B-41-1-2-1 will be more effective as parents due to their higher EBVs and more genetic diversity.

The molecular identification of maize dwarf mosaic virus (MDMV) and its effects on the morphophysiological traits of maize (Zea mays L.) was the focus of the presented research, intending to study the activity dynamics of two main types of enzymes, peroxidases, weakly binding to the membrane, and soluble peroxidases. The molecular identification of the virus engaged the use of the RT-PCR method. Results revealed that in the climatic conditions of Uzbekistan, red necrotic spotting, yellow mosaic with a large border on the edge of the leaf, curling of the leaves, yellow striped mosaic, and short stature all appeared in the maize plants. According to previous symptoms, the visual diagnostic methods used determine the maize yellow mosaic virus indications. In the existing study, the gene responsible for the protein coat synthesis (SR) nucleotide sequence served to diagnose the MDMV, and as a result, PCR tests showed yellow streaks on the leaves of maize plants. The mosaic and motility symptoms have been characteristic proofs of MDMV. The MDMV infects the maize plants in the initial growth phase (3–5 leaves), then the symptoms appear after a few days. Through morphological indicators, viral disease identification is possible at subsequent stages (6–7 leaves). Using spectrophotometry, the peroxidase enzyme activity in maize plants receives the virus infection to determine an early level of infectivity. The results confirmed that, in infected maize plants, peroxidase associated with the cell membrane was much more active than in control plants. It proves that contaminated Zea mays plants were in a stressful situation due to the virus. The RT-PCR method, widely used in diagnostics, sought to identify the virus species affiliation. PCR proceeded based on the virus соat protein (CP) gene.

Keywords: Maize (Zea mays L.), maize dwarf mosaic virus (MDMV), distribution, peroxidase, ascorbate peroxidase (APX), guaiacol peroxidase (GPX), thylakoid

Key findings: Given the participation of the peroxidase enzyme in the protection mechanism of the maize plants from MDVM disease, its consideration for use succeeded on local maize cultivars with high peroxidase activity, such as, Sherzod, and acclimatized cultivars, i.e., Extra Early Dightau-209 and Hickax, for the selection of virus-resistant cultivars.

One of the major tasks faced by wheat breeders in Uzbekistan is to enhance wheat genotypes’ adaptability to soil and other environmental conditions and improve the grain quality, making the country self-sufficient in wheat grains and later becoming an exporter. Better results are achievable using the world wheat collection, including the CIMMYT germplasm. Determination of the positive correlation of physiological traits of new wheat cultivars, the importance of physiological indicators of water balance with productivity, and the vital role of these indicators in productivity level were the chief concerns. The timely study evaluated heat resilience, rust resistance, and grain yield in bread wheat genotypes. Bread wheat germplasm obtained from CIMMYT with a background of artificial infection of yellow rust incurred scrutiny for their rust resistance. A 15% incidence was detectable in seven genotypes; however, necrosis quickly formed around the symptoms of the disease in plant leaves, preventing its further development. Resistant wheat accessions, i.e., 1088, 1164 (R), 1006, and 1251 (MR), occurred as moderately resistant, showing high leaf area and grain yield. The average value of the genotypes was low, mainly due to the two rust-resistant samples, and the 1000-grain weight was 34.8 g and 34.6 g, respectively, and the grains per spike and grain yield were lower than the average. The chlorophyll a and b, total chlorophyll, carotenoid content, relative water content, flag leaf area, and production traits of the genotypes К-1088 and К-1164 gained assessment, revealed to be physiologically effective under the field conditions of Tashkent, Uzbekistan. Quantitative indicators of the productivity of these wheat genotypes indicated positive differentiation. Selection ensued for promising accessions to develop initial sources for producing the wheat genotypes with rust resistance and high grain yield under the environmental conditions of Uzbekistan.

Keywords: Bread wheat (T. aestivum L.), wheat yellow rust, rust resistance, heat tolerance, leaf area, chlorophyll a and b, carotenoid, water content, grain yield

Key findings: By comparing with the standard check, a lower average value of the wheat accessions
was mainly due to the two rust-resistant genotypes, K-1164 and K-1289, which also have 1000-grain weights of 36.1 g and 34.8 g, respectively. The grain yield of these genotypes was also much lower than the average yield. Desirable chlorophyll a and b, total chlorophyll and carotenoid content, relative water content, leaf area of flag leaves, and higher grain yield were substantial in the wheat landraces К-1088, К-1082, and К-1164 and proved to be physiologically effective under environmental conditions of Tashkent, Uzbekistan. Quantitative indicators of the productivity of these accessions provided positive differentiation, with these genotypes recording higher values than the rest of the entries.

Besides the control treatment, Jabjabb date palm (Phoenix dactylifera L.) offshoots received irrigation water contaminated with heavy metals, lead(II) nitrate (Pb[NO3]2) = 300 mg kg^-1 and cadmium chloride (CdCl2) = 3 mmol. In addition to the control treatment, putrescine (500 mg L^-1), coumaric acid (500 mg L^-1), and 10 kg of palm^-1 zeolite entailed application to seedling soil. After nine months of alternately treating the seedlings with pollutants and therapies, preparing tissue slices of the study palm leaves succeeded. Lead and cadmium treatment adversely affected leaf anatomy and decreased epidermal, parenchymal, and vascular bundle markers to the lowest values. The study showed putrescine, coumaric acid, and zeolite improved leaf tissue anatomical properties and recorded the highest values. The enhancers reduced pollution, but putrescine improved the anatomical properties of leaves impacted by heavy metals, most especially lead. This interaction had the highest epidermis thickness, parenchymal cell diameter, primary and secondary xylem diameter, phloem thickness, bundle sheath thickness, vascular bundle length, and width (145.53, 214.17, 90.88, 77.13, 62.12, 30.21, 36.11, and 11.00 micrometers, respectively). By modulating the thickness of leaf tissue cuticles, the heavy metal factor and enhancers boosted the plant’s pollution resistance.

Keywords: Date palm (P. dactylifera L.), polyamines, zeolite, anatomical characteristics, palm offshoots, heavy elements, stress conditions

Key findings: Heavy metal pollution negatively affected the anatomical characteristics and showed decreased values of epidermal cells, parenchymal cells, and vascular bundles in leaf tissue of the date palm (P. dactylifera L.). Bioenhancers, such as putrescine, coumaric acid, and zeolite, improved the anatomical properties of leaf tissues.

This experiment transpired to determine the effect of the fungus Fusarium dimerum on the chlorophyll content and some phenotypic and anatomical morphological traits of the leaves of date palms (Phoenix dactylifera L.). The study results showed the ability of the fungus F. dimerum to cause infection on date palm leaves of five cultivars. The findings revealed that F. dimerum can secrete the enzymes cellulase, phenol oxidase, lipase, and amylases, as the area of their enzyme activity reached 6.1, 5.8, 6.2, and 12.4 mm, respectively. The results of histological analysis of the infected leaves also indicated the presence of F. dimerum spores in tissues of the infected leaves and the decomposition of cell walls and the loss of their integrated shape. The experiment showed significant differences in the chlorophyll content in healthy leaves and those infected with the fungus F. dimerum, wherein the percentage decreased in leaves infected with the fungus compared with the control treatment (healthy leaves).

Keywords: Date palm (P. dactylifera L.), Fusarium dimerum, histological anatomy, chlorophyll content in leaves, enzymes, fungal disease

Key findings: The results of the pathogenicity test for the fungus F. dimerum on the leaves of five cultivars of date palms (P. dactylifera L.) showed the ability of the fungus F. dimerum to cause infection and its ability to secrete the enzymes cellulase, phenol oxidase, lipase, and amylases. The ability to secrete enzymes plays a primary role in causing infection in the date palms.

In determining the best level of humic acid foliar application and suitable plant density and their effect on growth traits, yield components, and the quality of three safflower (C. tinctorius L.) cultivars, an experiment commenced during the winter crop season of 2019–2020 at two locations. The first location was Zmmaar Village, Mosul City, and the second location was in the Sallamiya Region, south of Mosul City, Iraq. The experiments had a randomized complete block design (RCBD) layout with factorial arrangement and three replications. Each experiment included three levels of humic acid (HA1: 0, HA2: 4, and HA3: 8 mg L^-1) with three plant densities (PD1: 46,296, PD2: 69,444, and PD3: 138,888 plants ha^-1) and three safflower cultivars (C1: Goldasht, C2: Oleic Leed, and C3: Aswan). The safflower with a humic acid concentration of 8 mg L^-1 resulted in a significant increase in growth, yield, and quality traits compared with the lowest concentration (4 mg L^-1) and the control treatment in both locations. Plant density (46296 plants ha^-1) was superior by giving the highest seed yield per plant, biological yield, harvest index, oleic and linoleic acid, and oil and protein percentages for both locations. The safflower cultivar Aswan achieved the highest rate of growth, productivity, and quality traits compared with cultivars Oleic Leed and Goldasht at both locations.

Keywords: Safflower (C. tinctorius L.) cultivars, humic acid, plant density, seed yield, biological yield, harvest index, oleic and linoleic acid, oil and protein percentage

Key findings: The safflower (C. tinctorius L.) cultivars with humic acid foliar application (8 ml L^-1) resulted in a significant increase in growth, yield, and quality traits compared with the lowest concentration (4 ml L^-1) and the control treatment in both locations.