Morphophysiological aspects of ornamental sunflowers cultivated in different growing seasons under semi-arid conditions

ABSTRACT Knowledge of how climatic conditions affect plant morphophysiology is essential for understanding how to manage the growth cycles of different crops. The aim of this study was to evaluate the effects of the growing seasons in a semi-arid area on the morphophysiological variables of ornamental sunflower plants. The experiment was carried out in a randomized block design in a split-plot arrangement with four replicates. Six cultivars (‘Bonito de Outono Sortido’, ‘Sol Noturno’, ‘Sol Vermelho’, ‘Jardim Amarelo Alto’, ‘Girassol F1 Sunbright Supreme’ and ‘Girassol F1 Vincents Choice’) were evaluated in the main plots and two different growing seasons (GS) in the subplots (GS1 - warm climate and GS2 - mild climate). Evaluations of gas exchange, chlorophyll indices, and leaf surface area were carried out at the reproductive stage (R5.5). The cultivation of ornamental sunflowers in semi-arid regions was significantly affected by the growing season. Changes in gas exchange variables and the morphophysiology of ornamental sunflower plants in the two growing seasons reflected the high phenotypic plasticity characteristic of this species. The cultivation of ornamental sunflowers under semi-arid conditions in the growing season, when air temperature and solar radiation are high, could be limited due to elevated transpiration rates. Therefore, it is recommended that they are grown mainly during the moderate climatic season in semi-arid regions.

Varietal features of photosynthetic activity of Tyumen seed oats when applying mineral fertilizers

The purpose is to study the varietal characteristics of the photosynthetic efficiency of oats when applying fertilizers in Western Siberia. Methods. The research was carried out on an experimental field located in the northern forest-steppe of the Trans-Urals. Photosynthetic potential and net productivity of photosynthesis were determined by the Nichiporovich’s method. Results. The nature of the formation of the assimilation surface and the accumulation of biomass of oat varieties Otrada, Talisman and Foma at different levels of mineral nutrition was studied. The photosynthetic potential and the net productivity of photosynthesis are calculated. The share of the influence of weather conditions, agrophone and variety on the studied indicators is determined. The Foma variety was characterized by maximum leafiness, compared to the Talisman and Otrada. On a natural agrophone, its assimilation surface in the sweeping phase reached 36.0 ± 5.5 thousand m2, at Otrada and Talisman – 28.1 and 24.0 thousand m2 per 1 ha of sowing. A very strong variability of the leaf surface area in Otrada was revealed (Cv = 24 %). The use of mineral fertilizers enhances the development of the leaf apparatus by 44–50 % and causes competition between oat plants. A close positive correlation was revealed between the leaf area in the sweeping phase and yield (r = 0.72). The area of the assimilation surface of oats is affected by: weather conditions – 37 %; nutrition level – 30 % and variety – 25 %. It was found that the Otrada and Foma varieties have the same accumulation dynamics and form the maximum photosynthetic biomass by the sweeping phase. The nature of biomass accumulation depends on weather conditions by 39 %; on mineral fertilizers by 29 % and on the genotype of the variety by 17 %. The productivity of the studied varieties is formed by increasing the assimilation surface, rather than increasing the efficiency of photosynthesis. Scientific novelty. For the first time, the photosynthetic potential was determined and the efficiency of the net photosynthesis productivity of oat varieties of the Tyumen selection was revealed. The share of the influence of various factors in the formation of the oat crop in the conditions of the Northern Trans-Urals has been established.

Efficiency of soybean photosynthesis as affected by the components of cultivation technology

Purpose. Determine the efficiency of photosynthesis of soybean varieties ‘Ustia’, ‘Kordoba’, ‘Estafeta’ as affected by the use of microfertilizers and growth regulators. Methods. Field, laboratory. Results. The article presents the results of research to study the effectiveness of photosynthesis in the cultivation of different varieties of soybean. It was found that the treatment of plants with microfertilizer Yara Vita Mono Molitrak in the budding phase (0.25 l/ha) + in the flowering phase (0.25 l/ha) in combination with the growth regulator Radostym ensured a leaf area (1000 m2/ha) increase of 7.2 m2/ha in variety ‘Ustia’, 7.6 in ‘Kordoba’ and 5.2 in ‘Estafeta’, compared to control. At the same time, the efficiency of using the growth regulator Biosil against the background of double treatment with the microfertilizer was at the level of the treatments with single treatments with Yara Vita Mono Molitrak in the budding phase (0.25 l/ha) in combination with appropriate growth regulators. Conclusions. It was investigated that the leaf surface area of ‘Ustia’ variety with foliar fertilization using Yara Vita Mono Molitrak microfertilizer in the budding phase (0.25 l/ha) in combination with growth regulators Biosil and Radostym was 38.8 and 39.2 thousand m2/ha. The use of microfertilizers twice in combination with the above-mentioned growth regulators contributed to the increase of leaf area to the level of 38.9 and 39.5 thousand m2/ha, respectively. Similarly, in ‘Kordoba’ soybean variety, the best option was the use of Yara Vita Mono Molitrak in the budding phase (0.25 l/ha) + in the flowering phase (0.25 l/ha) in combination with the growth regulator Radostym, which helped to increase the leaf area to 39.5 thousand m2/ha. Foliar fertilization with microfertilizers combined with the use of growth regulators provides the formation of maximum NPP. Thus, in ‘Ustia’ variety, it was 1.47 and 1.45 g/m2, in ‘Estafeta’ 1.82 and 1.82 g/m2 of dry matter per day.

Effect of condit soil improver on growth, yield and leaf mineral content of two summer pear cvs. with interstocks

The study involving 2 pear cultivars was conducted in 2006–2016. ‘Radana’ and ‘Clapp’s Favourite’ were planted in the spring 2006 in the Experimental Station next to Wrocław (south-western Poland) on Quince S1 and Caucasian pear seedlings with 2 interstocks – ‘Doyenne du Comice’ and ‘Pyrodwarf’. An annual dose of 3 tonnes per hectare of Condit Basic bio-fertilizer was applied onto the tree row soil surface at the beginning of March 2012, i.e., starting from the 7th year after the planting. The study objective was to evaluate effect of Condit preparation on summer pear tree cultivars which are not compatible with Quince, and to assess interstock suitability in their context. The yields obtained in the first eleven years following tree planting were the most abundant for ‘Radana’ on Caucasian pear and on Quince with ‘Doyenne du Comice’ interstock. When applied for 5 years, Condit increased the leaf surface area, however a significant difference was exhibited only by ‘Radana’ on the Caucasian pear. This soil improver did not affect tree growth and yielding; total chlorophyll content; foliar Mg, P, Ca, and K; and mean fruit mass across the investigated treatment combinations.

Effect of Tomato Yellow Leaf Curl Virus Infection on Some Growth Indicators of Pepper Hybrids Grown Under Plastic House Conditions in Lattakia Governorate, Syria

Hamdan, R.S., I.D. Ismail and I. Akel. 2021. Effect of Tomato Yellow Leaf Curl Virus Infection on Some Growth Indicators of Pepper Hybrids Grown Under Plastic House Conditions in Lattakia Governorate, Syria. Arab Journal of Plant Protection, 39(4): 309-316. https://doi.org/10.22268/AJPP-39.4.309316 This study aimed to evaluate the effect of Tomato yellow leaf curl virus (TYLCV) infection on some growth parameters of several pepper hybrids grown under protected cultivation along the Syrian coast. Four pepper hybrids (Capsicum annum) were tested, two hot (Lahab, Sirad) and two sweet (Nevada, Dallas) peppers. The research was carried out during the 2020-2021 growing season in a plastic house at the Agriculture Scientific Research Center in Lattakia, using a randomized complete block design, with 8 treatments, three replicates and 5 plants per replicate. The results obtained showed that the sweet pepper hybrids (Nevada, Dallas) were more sensitive to infection with Tomato yellow leaf curl virus than the hot pepper hybrids (Lahab, Sirad), without significant differences among them. The pepper hybrid Nevada did not show any apparent symptoms, and the effect of the virus on some growth parameters (number flowers, flower setting, and the leaf surface area) was evident in comparison with other hybrids, but the differences were not significant. The Dallas, Sirad and Lahab pepper hybrids showed visible symptoms in response to infection with infection rate of 93.33%, 80% and 80%, respectively. The effect of virus infection on the growth parameters of these hybrids was variable. The reduction in the flowers number of Nevada, Dallas, Cirad and Lahab after 45 days of infection was 33%, 31.10%, 10.23% and 5.07%, respectively, and also with a reduction in the number of flowers setting of 77.39%, 20.87%, 23.33% and 66.68%, respectively. The same was true for the leaf surface area, where reduction rate for the Nevada, Dallas, Sirad and Lahab hybrids 30 days after infection was 48.17%, 53.06%, 16.45% and 36.6%, respectively. Keywords: Tomato yellow leaf curl virus, pepper hybrids, growth parameter, host resistance, protected agriculture.

Effect of irradiation on the growth and rooting of a climbing rose in vitro

The article presents the influence of pulsed and continuous irradiation (400…780 nm) on in vitro growth of the climbing rose variety “Camelot” at the illumination of 80±5 mmol/(m2s), temperature - 24±10C, and the relative air humidity - 73±2%. It was found that the experimental led light (LED) pulsed phytoirradiator contributed to a significant increase in the leaf surface area during cultivation of climbing rose microstems in Gamborg’s nutrient medium, the average growth was 2.94 mm2 compared to 2.80 mm2 in the control. Pulse irradiation increases the reproducibility of climbing roses by 1.7 times, and also increases the rooting rate up to 96% compared to 82% in the control. Experimental LED phytoirradiator of continuous irradiation promoted an increase in the leaf surface area growth at the level of the control luminescent phytoirradiator, but also provided a significant increase in the reproduction factor and rooting rate of rose microstems. In the pulsed mode, phytoinstallations consume only 50% of the electricity compared to the continuous irradiation mode.

Dynamics of physiological and biochemical indicators of apricot cultivars under water stress

The results of the study of drought resistance of 4 cultivars Prunus armeniaca Lam bred in the Nikitsky Botanical Gardens are presented. The dynamics of indicators of the water regime of leaves, the content of photosynthetic pigments and phenolic compounds in them has been studied. As a result of the research, information was obtained on the physiological and biochemical characteristics of apricot against the background of adaptation to stressful conditions created by moisture deficit during the summer drought on the Southern Coast of the Crimea. Significant differences were revealed in the ability to retain moisture during wilting, the ability to restore tissue turgor after critical dehydration, the concentration of chlorophylls and phenolic substances in the cultivars of different resistance to water stress. The promising drought-resistant genotypes 'Professor Smykov' and 'Kazachok' have been identified, demonstrating a relatively high level of water-retaining forces of leaf tissues and reparation of the leaf surface area.

First Report of Anthracnose of Gossypium indicum Lam. caused by Colletotrichum theobromicola in Korea

In September 2020, typical anthracnose symptoms were observed on cotton (Gossypium indicum Lam.) leaves growing in Hahoe village, Andong, Gyeongbuk Province, Korea. The leaves of the infected plants initially showed spots with halo-lesions which became enlarged and spread to the entire leaf surface area. The infected leaves later became yellowish and chlorotic (Fig. 1A). The disease incidence was at least 90% in the field. For pathogen isolation, fresh samples collected from symptomatic leaves were cut into small pieces (4 to 5 mm2), surface-sterilized in 1% sodium hypochlorite for 1 min, rinsed three times, and macerated in sterile distilled water (SDW). They were spread onto potato dextrose agar (PDA) plates and incubated at 25 °C for 5 days under a 12-h photoperiod. Five isolates were recovered from the infected leaves. Purified fungal colonies were initially white, later turned yellow on PDA medium. Conidia were yellow-colored, smooth-walled, aseptate, straight or slightly distorted, and cylindrical with one end slightly acute or with broadly rounded ends, and with size ranges from 15.3 to 17.5 µm (length) × 4.5 to 5.2 µm (width) (Fig. 1B). The morphological characteristics of the present isolates were consistent with those of Colletotrichum gloeosporioides (Weir et al. 2012). A single isolate, ANUK97, was selected for identification. The multilocus sequence analysis (MLSA) of the actin (ACT), calmodulin (CAL), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), internal transcribed spacer (ITS) rDNA, and β-tubulin (Tub2) were amplified by PCR with the primer pairs of ACT-521F/ACT-783R, CL1C/CL2C, GDF/GDR, ITS1/ITS4, and T1/T2, respectively (White et al. 1990). The resulting sequences were deposited in GenBank under accession numbers MW580367 (ACT), MW580368 (CAL), MW580369 (GAPDH), MW580370 (ITS), and MW580371 (TUB2). A nucleotide BLAST search revealed that ACT, CAL, GAPDH, ITS, and TUB2 sequences be 99% similar to accession numbers MN307380.1, MH155176.1, MK796226.1, MW580370.1, and JX010377.1, respectively of C. theobromicola. Maximum likelihood (ML) phylogenetic analysis was conducted based on a combined dataset of ACT, CAL, GAPDH, ITS, and TUB2 sequences using MEGA-X 10.1.8. The isolate ANUK97 was clustered with a representative strain C. theobromicola CBS124945 100% bootstrap support (Fig. 2). For the pathogenicity test, two-month-old cotton seedlings (n = 10) were inoculated with conidial suspensions (10⁶ spore/mL) of C. theobromicola obtained from 7-day-old PDA cultures at 25 °C by spray method. Seedlings treated with sterile distilled water served as controls. Inoculated and control cotton plants were incubated in the greenhouse at 25 °C under a 12-h photoperiod. After 7 days, necrotic lesions were observed on the artificially inoculated cotton plants, while control plants did not develop any disease symptoms. The pathogen was re-isolated from infected cotton leaves, but not from control plants to fulfill Koch’s postulates. To our knowledge, this is the first report of anthracnose of cotton caused by Colletotrichum theobromicola in Korea.

The models of soybean varieties adapted to dry conditions

The article presents the analysis of early-ripening and mid-ripening promising and cultivated soybean varieties that received a comprehensive evaluation under irrigation conditions over the past period (2016-2018) of breeding with the increase in atmospheric drought and dry hot wind days to 77 with a long-term average annual indicator of 47 days with a relative humidity of less than 30%. We developed the scientifically based model of highly productive soybean varieties (2021-2023) with a yield of 2.8-3.8 t/ha and the growth season of 105-122 days. The model is based on the established correlations of the main morphological and biological characteristics with the grain productivity of irrigated sowing. The model of soybean varieties reflects characteristics that ensure the responsiveness of plants to watering and resistance to prolonged manifestations of atmospheric drought: a long growth season, low linear plant growth, significant leaf surface area, photosynthetic potential, dry biomass yield, number of plants before harvesting, thousand-seed weight, long-term duration of the “flowering-beans filling” period. The model is complemented by the indicators of high protein and fat content in seeds, as well as their yield from a unit of harvesting area.

Growth stimulators and mineral fertilizers influence on Sudan grass growth, development and productivity

The article considers the results of research on the influence of seeding rates, fertilizers and growth stimulator on the development and productivity of the Sudan grass of the Julia variety in the conditions of chestnut soils of the Volgograd region. In the field two-factor experiment, we studied: factor A - the three seeding rates 1.0, 1.5 and 2.0 million germinating seeds per hectare; factor B - fertilizers and growth promoters: 1. Control without fertilizers; 2. N60 P60 K45 + N30; 3. Growth stimulator Raikat Start; 4. N60 P60 K45 + Raikat Start + N30. The use of mineral fertilizers increased the leaf surface area by 0.3-0.5 thousand m2/ha, the use of growth stimulators increased the leaf surface area by 0.1-0.2 thousand m2/ha, the combined use of mineral fertilizers and growth stimulators increased the leaf surface area by 0.9-1.2 thousand m2/ha. It was found that the highest yield of green mass of Sudan grass, 28.6 t/ha, was formed on the variant with a seeding norm of 1.5 million tons of germinating seeds per ha with the complex application of mineral fertilizers and the growth stimulator Raikat Start.