Volumen 29 (2021): Edición 2 (December 2021)

A thorough understanding of plant behavior at different growth stages is of paramount importance for fruit quality improvement, the regulation of production periods, and reduced fruit production costs. There are as many as three waves of flowering in evergreen pomegranate cultivars – i.e., during the spring, rainy, and autumn seasons. However, for securing enhanced production of superior quality fruits as well as profit to the growers, crop regulation is required. This can be achieved by forcing the tree to rest at a particular stage and by producing abundant blossoming and quality fruits during any one of the three flushes. Observations on phenological phases would help in understanding the dates of specific stages of crop development, which in turn enable the growers to plan, organize, and carry out timely schedules of agronomic practices such as irrigation, fertilization, and crop protection. Therefore, there is a need to evaluate the response of pomegranate under different environmental conditions to identify a suitable flowering season to produce a better quality of fruits with consistent yield, and to enable standardization of management practices for optimum production based on phenological stages.

Freesia hybrida is one of the most important cut flowers with a short vase life. The present study was conducted to explain the effect of the two planting dates December 1st and 15th and soaking corms before planting in gibberellic acid at concentrations of 0, 75, and 150 mg·L⁻¹ on the growth, flowering, and flowers quality of Freesia hybrida ‘Corona’. A larger diameter of the inflorescence stem and floret head, fresh weight of inflorescence, and longer vase life were obtained when planted on December 1st. Soaking the corms in a GA₃ solution of 150 mg·L⁻¹ before planting significantly extended the vase life compared to the control. Finally, it can be concluded that the planting of corms soaked in a solution of 150 mg·L⁻¹ GA₃ on December 1st in unheated greenhouses can improve the growth, development, and quality of flowers of Freesia hybrida ‘Corona’.

Orchids (Phalaenopsis) are ornamental plants that are cultivated commercially and in great demand in the market. Soft-rot disease (SRD) caused by the necrotrophic pathogen Dickeya dadantii is a cause of considerable economic loss to cultivators of many orchid species. Our previous experiment identified a limited number of species that were resistant to D. dadantii. This study aimed to validate the resistance level of four Phalaenopsis species in a detached leaf inoculation protocol to identify the resistance mechanism(s) involved. Soft-rot symptom diameter was measured from 6 to 18 hours post-inoculation (HPI) with D. dadantii. Disease assessment confirmed that P. amboinensis is a resistant species, P. pantherina is a susceptible species, and P. amabilis and P. schilleriana are very susceptible species. There was no difference in the lignin content between the resistant and very susceptible species. Detailed observation of resistant and very susceptible species, P. amboinensis vs. P. amabilis, revealed higher phenylalanine ammonia-lyase (PAL) and peroxidase (POD) in P. amabilis than in P. amboinensis. In contrast, there was higher salicylic acid (SA) content in P. amboinensis than in P. amabilis. These results suggest that POD and PAL activities may not be effective in defense against soft-rot disease, while SA plays an important role in the resistance of P. amboinensis to D. dadantii. Low PAL activity in P. amboinensis implies that the SA contents from the isochorismate pathway may be involved in the mechanism of P. amboinensis resistance to D. dadantii. Therefore, endogenous SA content may be a good indicator for screening resistant species in Phalaenopsis.

Biomass partitioning is one of the pivotal determinants of crop growth management, which is influenced by environmental cues. Light and CO₂ are the main drivers of photosynthesis and biomass production in plants. In this study, the effects of CO₂ levels: ambient 400 ppm (a[CO₂]) and elevated to 1,000 ppm (e[CO₂]) and different light intensities (75, 150, 300, 600 μmol·m⁻²·s⁻¹ photosynthetic photon flux density – PPFD) were studied on the growth, yield, and biomass partitioning in chrysanthemum plants. The plants grown at higher light intensity had a higher dry weight (DW) of both the vegetative and floral organs. e[CO₂] diminished the stimulating effect of more intensive light on the DW of vegetative organs, although it positively influenced inflorescence DW. The flowering time in plants grown at e[CO₂] and light intensity of 600 μmol·m⁻²·s⁻¹ occurred earlier than that of plants grown at a[CO₂]. An increase in light intensity induced the allocation of biomass to inflorescence and e[CO₂] enhanced the increasing effect of light on the partitioning of biomass toward the inflorescence. In both CO₂ concentrations, the highest specific leaf area (SLA) was detected under the lowest light intensity, especially in plants grown at e[CO₂]. In conclusion, elevated light intensity and CO₂ direct the biomass toward inflorescence in chrysanthemum plants.

Female and male plants of difficult-to-root species Leucadendron elimense subsp. elimense were investigated for rooting potential with three rooting hormones: indole-3-acetic acid (IAA), 1-naphthaleneacetic acid (NAA), and indole-3-butyric acid (IBA) at three different concentrations (2000 ppm, 4000 ppm, and 6000 ppm). The experiment was made under essential misting, bottom heat, and a naturally ventilated greenhouse. After 18 weeks the experiment terminated and callusing and rooting percentage, root number, and root length were determined. Female cuttings rooted in the highest percentage (80%), root number (>30), and root length (close to 100 mm) after treatment with IAA at 4000 ppm. Under the above treatment male cuttings rooted in 70%, with a mean root number of 24 and root length of 90 mm. The efficient rooting results could aid in saving the species in its natural habitat and supporting restoration ecology, as well as introducing this species into the flower market.

Callus induction and plant regeneration are important steps of in vitro plant breeding of ornamental plants. In this study, the effects of different combinations of plant growth regulators (PGRs), promoters, and minerals on callus induction and plant regeneration in different carnation cultivars were studied in a completely randomized design with three replications. For callus induction, 16 different combinations of 2,4-dichlorophenoxyacetic acid (2,4-D), 6-benzylaminopurine (BA), 1-naphthaleneacetic acid (NAA), and casein hydrolysate (CH) were studied using in vitro leaf explants. The Murashige and Skoog (MS) medium supplemented with 0.2 mg·dm⁻³ of 2,4-D and 200 mg·dm⁻³ of CH showed the highest frequency of callus induction. Among the cultivars, ‘Noblesse’ showed the highest rate of callus induction (91.67%). Regarding regeneration, BA, NAA, silver nitrate (AgNO₃), and adenine hemisulfate (As) were used in ten different combinations. The ‘Cameron’, ‘Tabasco’, and ‘Noblesse’ cultivars with 95.24% regeneration percentage showed the highest rate of plant regeneration. Generally, in most cultivars, the highest regeneration rate and shoot number per explant were found in the MS medium supplemented with 3 mg·dm⁻³ of BA, 0.6 mg·dm⁻³ of NAA, 5 mg·dm⁻³ of AgNO₃, and 40 mg·dm⁻³ of As. According to the results, the highest regeneration frequency was obtained when 40 mg·dm⁻³ of As was added to the medium. Finally, the flow cytometry analysis indicated that there were no significant differences between in vitro regenerated and control plants in terms of DNA ratios.

This study evaluated some physiological and biochemical changes that accompanied the growth stages of custard apple cultivated in Lang Son, Vietnam. Regarding the pigment content of the peel, the research results showed that the content of chlorophyll a, b, and total reached the highest value at week 13, then decreased rapidly when the fruit entered the ripening stage. Meanwhile, carotenoid content in the peel increased gradually from week 3 until complete ripening at week 16, from 0.014 to 0.063 mg·g⁻¹ fresh peel. Protein, lipid, and tannin content in the fruit flesh decreased gradually from week 3 to maturity. The vitamin C and reducing sugar content tended to reduce in week 3 to 7, then increased again until the fruit ripened. While the starch content varied quite complicatedly, it decreased from week 3 to 7, increased again from week 9 to 13, then decreased sharply as the fruit entered the ripening stage (down from 10.011% at week 13 to 1.795% at week 16). Regarding enzyme activity, α-amylase and peroxidase activity increased during the fruit development stages, corresponding to week 3 to 15 in this study. At week 16, the peroxidase activity continued to increase, while the α-amylase activity began to decrease. Unlike these two enzymes, catalase activity gradually increased from fruit formation to the 11th-week fruit stage, reaching 11.542 µM H₂O₂·g⁻¹·min⁻¹, and then decreased rapidly to 3.167 µM H₂O₂·g⁻¹·min⁻¹ in the 16th-week fruit stage.

The study evaluated the possibility of using the image acquisition and processing method with ImageJ software for estimating growth vigor and flowering intensity of ‘Conference’ pear trees. For assessing flowering intensity, manual counting of flower clusters and taking of photographs of the trees were conducted at full bloom. Tree vigor was estimated by manually measuring the total length of the central leader and shoots of individual trees. The trees were photographed from the same distance using a hand-held camera. The calibration model for assessing the vigor or flowering of trees by image analysis was based on measurements and photographs taken for nine selected trees differing in the total length of shoots or in the number of flower clusters. Then, a quality assessment of the model was carried out on 26 nonselected trees. Image processing was performed using ImageJ software. High regression coefficients were obtained between the surface area of petals measured on the photographs and the number of inflorescences counted (r² = 0.98); however, observations carried out in the following year indicate the need for individual calibration of estimation models in each evaluation season. Subsequently, the quality of estimating the flowering intensity of pear trees was assessed using a previously determined calibration model. Mean absolute percentage error (MAPE) values ranged from 14.0% to 21.8%, depending on the measurement time. In the assessment of tree growth vigor, a high correlation (r² = 0.98) was also obtained between the actual length of shoots measured individually for each tree and the values obtained by analyzing the photographic image, where the MAPE error was 12.9%.

As a result of the evaluation of the physical and biochemical quality indicators of the fruit of thirteen apple cultivars of Ukrainian breeding, it was found that the fruits of ‘Teremok’, ‘Skifs’ke Zoloto’, ‘Amulet’, ‘Perlyna Kyieva’, ‘Harant’, ‘Edera’, ‘Radohost’, ‘Todes’ and ‘Askol’da’ are characterized by high stability of market traits based on the maximum diameter of the equatorial dimension, which varies depending on the cultivar, from 70 mm to 78 mm. The firmness of the fruit flesh of the evaluated cultivars in the harvest maturity was over 7.0 kg·cm⁻² but in ‘Solomiya’ and ‘Dmiana’ this indicator was 11.1 kg·cm⁻². The fruits of ‘Harant’ and ‘Todes’ were distinguished by a high dry matter content (over 18%). The highest content of soluble solids (14.5%) was accumulated in the fruits of ‘Dmiana’, and the maximum amount of sugars (11.6%) in the fruit of the ‘Ornament’. The fruits of ‘Teremok’, ‘Skifs’ke Zoloto’, ‘Amulet’, ‘Edera’, ‘Perlyna Kyieva’, ‘Kateryna’ and ‘Dmiana’ were characterized by excellent taste quality based on the values of the sugar-acid index (20–25). In the fruits of ‘Kateryna’, ‘Dmiana’ and ‘Solomiya’, a stable pectin content (over 1%) was found. The fruits of ‘Harant’ accumulated a high content of ascorbic acid (11.5 mg·100 g⁻¹ of fresh weight), while ‘Kateryna’, ‘Radohost’, ‘Solomiya’ and ‘Askol’da’ contained over 240 mg·100 g⁻¹ of fresh weight of polyphenols. According to the complex of the quality indices, the fruits of ‘Teremok’, ‘Skifs’ke Zoloto’, ‘Perlyna Kyieva’, ‘Askol’da’ and ‘Dmiana’ were distinguished by high commercial value and excellent consumption properties. The fruits of ‘Kateryna’, ‘Ornament’, ‘Dmiana’ and ‘Solomiya’ were characterized by stable carbohydrate content, while ‘Harant’ and ‘Askol’da’ by a stable high content of ascorbic acid and polyphenols, respectively.

Two biostimulants, RutfarmMaxifol (Ascophyllum nodosum extract 17.5%, amino acids, macro- and microelements, Agromaster, Russia) and Radifarm (polysaccharides, glycosides, amino acids, and micro-elements; Valagro, Italy), were applied at different concentrations on tomato plants of the hybrid cultivar ‘Merlice’, grown under a hydroponic system. Biostimulants were applied in the form of seed soaking and twice as foliar sprayings at flowering and at the initial fruit development stages. Biostimulants were applied as water solutions at concentrations of 2.5, 5.0, and 7.5 mg·L⁻¹. Plant growth, productivity, and fruit quality parameters were determined at three points: 35, 70, and 105 days after seeding. All biostimulant treatments resulted in higher values of growth parameters and yield productivity in relation to the control. The application of biostimulants improved the parameters of the fruits’ quality by increasing the total soluble solids and antioxidants, ascorbic acid, and carotenoid contents but it did not affect tomato fruit acidity; therefore, tomato fruits from the treated plants were tastier than those from control.

Natural farming is a type of low-input sustainable agricultural system that is characterized by the avoidance of the use of any animal materials. Production of self-produced seeds by farmers is recommended under natural farming environments, with an expectation of improved crop growth and yield. However, there have been no scientific studies that investigated the performance of self-produced seeds under natural farming. This study investigated the germination rate, growth, and yield of carrots (Daucus carota L.) from different seed sources under natural farming. The main experimental factor was the cultivation method: CT – control; CF – conventional farming; NF1 – natural farming with tillage and compost input; and NF2 – natural farming without tillage and compost, and the subfactor was the seed source: OPN – open-pollinated seeds self-produced under natural farming; OPC – open-pollinated seeds produced under conventional farming; and HB – hybrid seeds. The germination rate of OPN seeds was higher than that of other seeds. In addition, root fresh weight and other root parameters of OPN were as high as for HB seeds. This suggests that using self-produced seeds by farmers improves crop performance in a natural farming system.

The world population is elevating rapidly, the demand for fruits and vegetables is increasing due to their nutritional value, and the concerns regarding the quality have been amplified. Therefore, the development of various techniques to retain quality attributes, and shelf-life extension of food has become a focal point for researchers and food industries. One of the economical techniques used for the preservation of food is the application of edible coating onto the surface of fresh or minimally processed fruits and vegetables. The foremost advantage of edible coating is that it is eco-friendly. Edible coatings can improve nutritional quality along with the maintenance of physiological attributes of fruits and vegetables. It can also act as a vehicle to carry active components, such as essential oils and spices that also carry antioxidant and antimicrobial properties. The application of nanotechnology for the formulation of edible coating is playing a significant role and aids in the reduction of microbial load on fruits and vegetables. The main aim of this review is to bring up-to-date information regarding various edible coatings used on minimally processed fruits and vegetables – carbohydrates, proteins, lipids, composites, fruit purees, and herb-based edible coatings and their significant effect on the physiological properties of produces. The information will be beneficial for the researchers and scholars to study the various effects of edible coatings on minimally processed fruits and vegetables.