International Journal of Horticultural Science and Technology
Volume:11 Issue: 3, Summer 2024

The irresponsible use of chemical fertilizers and pesticides in agricultural production has caused significant environmental impacts and damages to human health. This study aimed to explore the effects of extracts from several Iranian medicinal plants on tomato growth under greenhouse conditions. A completely randomized design was used and the treatments included methanolic extracts of Taraxacum officinale L., Conocarpus erectus L., Allium jesdianum L., Rheum ribes L., Dorema aucheri L. and Juniperus sabina L. at three concentrations of 1000, 5000, and 8000 mg/L. The measured variables were stem length (SL), internode distance (ID), branch number (BN), auxin content (AC), cytokinin content (CC), auxin/cytokinin ratio, total protein, total phenol content (TPC), total flavonoid content (TFC), and anti-oxidant potential (FRAP). Under greenhouse conditions, foliar spraying with Dorema aucheri plant extract (8000 mg/L) significantly increased the stem length by 15% compared to the control. Rheum ribes extract (8000 mg/L) resulted in an increase (19%) in internode distance. However, the number of branches decreased by 34% in response to the plant extracts. Compared to the control, the amount of cytokinin decreased after spraying, whereas the auxin content showed a sinusoidal trend of change. In response to all treatments, the auxin/cytokinin ratio increased, with the highest value observed in plants treated with Allium jesdianum extract (5000 mg/L). According to the results, the plant extracts proved effective and assisted in tomato growth. Future research may aim to identify the effective biological compounds in these extracts.

Since processing may affect the quality and benefits of foods, a study was conducted to compare some properties of fresh, sun-dried (constant water content of 4%) and oven-roasted (130 °C for 25 min) pistachio nuts of two cultivars. Carotenoid, iron, copper, manganese, and total saturated, total unsaturated, palmitic and linolenic fatty acids showed no statistical difference (P ≤ 0.05) among the samples. Comparing ‘Akbari’ cultivar, ‘Ahmadaghaei’ cultivar had less anthocyanin and less palmitoleic acid. Drying and roasting reduced antioxidant activity, flavonoid content, and arachidonic acid content, while increased kernel firmness, malondialdehyde and hydrogen peroxide. Chlorophyll content was higher in dried and roasted than fresh status in both cultivars. Stearic acid had a stable content in ‘Ahmadaghaei’, but increased by drying and roasting in ‘Akbari’. Oleic acid increased by drying and roasting in ‘Ahmadaghaei’. In ‘Akbari’, oleic acid first decreased by drying and then increased to the initial level by roasting. Linoleic acid decreased by drying and roasting in ‘Ahmadaghaei’. In ‘Akbari’, it revealed an increasing trend by drying, but again decreased to the initial content after roasting. It was concluded that the condition which was used in this experiment for drying and roasting the pistachios was not harmful and had some advantages which lead to better storage of pistachios.

Different culture media have a variety of materials that impact a plant’s root system architecture (RSA) and root system quality. Finding the most compatible RSA of cucumber seedlings among the eight mixed culture media is critical to plant productivity. In this experiment, cucumber seeds were sown in the eight mixed culture media including a volume ratio of 30:10:60 of 1- perlite-vermicompost-coco peat as the control group, 2- peat moss-vermicompost-palm peat, 3- cocopeat-vermicompost-palm peat, 4- perlite-vermicompost-palm peat, and a 30:70 of 5-peat moss- palm peat, 6- cocopeat -palm peat, 7- perlite -palm peat and 8- vermicompost-palm peat under greenhouse conditions and RSA of the seedlings were evaluated by GiA-Roots software via their images, at four-leaf stage. The results showed that the minimum network length, network area, and network perimeter (821.6 cm, 7598.3 cm2, and 2102.3 cm, respectively) observed in seedlings grown on perlite-vermicompost-coco peat (control) which lacked palm peat, as well as the minimum network volume, number of connected components, and network depth were observed in control. While, the maximum network length, network volume, number of connected components, network width, network area, and network perimeter (88862.8 cm, 2076390.9 cm3, 23.2, 4567.4 cm, 332356.1 cm2, and 132068.9 cm, respectively) observed in seedlings grown under peat moss-vermicompost-palm peat (30:10:60). As a result, a culture medium containing 30% peat moss, 60% palm peat and 10% vermicompost improved RSA in cucumber seedlings and palm peat was recommended as a sustainable component of the culture medium in cucumber seedlings as a natural and local biological resource.

The present research considered identifying drought tolerant genotypes through an index-based analysis of stress tolerance and physiological traits in pomegranates. Ten local pomegranate genotypes in Iran were evaluated for drought stress tolerance in two different irrigation regimes, i.e. normal conditions and severe drought stress (SDS). The experiment was arranged in a randomized block design with three replications and took two consecutive years to accomplish (2019-2020). Indices for stress tolerance were estimated from the fruit yield of a single tree under each irrigation regime. There were significantly positive correlations among several parameters, including Yp (fruit yield under normal condition), Ys (fruit yield under SDS), mean productivity (MP), geometric mean productivity (GMP), stress tolerance index (STI), and proline (Pro) content. Therefore, these indices were applicable to the identification of drought tolerant genotypes under SDS and normal conditions. The Pro content was introduced as the best physiological index to assist in the indirect selection of drought-tolerant genotypes. Meanwhile, a negative correlation was noticed between Ys and stress susceptibility index (SSI). This index may assist in identifying susceptible genotypes. Based on principal component analysis (PCA), two genotypes (MTS and PSS) performed best in terms of fruit yield and showed a high Pro content under the SDS condition.

Worldwide warming enhances the rainfall irregularity, makes a downfall in water resources. Drought is one of the main limiting parameters for agricultural production, which includes fruit. In this study, a standard method for measurement of dehydration tolerance was established to evaluate the degree of drought tolerance in Fragaria, the simplest genomic model in the Rosaceae, which comprise important fruit species like almond, apple, plum, etc. As a quick screening method for monitoring Fragaria genotypes in response to dehydration, a short-term water deficit experiment was performed, and two eco-physiological parameters associated with leaf water status, leaf relative water content (RWC), and leaf water losing rate (WLR) were measured in a total of 20 strawberry cultivars (Fragaria × ananassa Duch.) from different breeding programs, as well as two ecotypes of the European diploid species F. vesca and one American octaploid species F. chiloensis. Fragaria genotypes were characterized in their response to drought stress by measurement of WLR and RWC, DNA fingerprints was performed for selected Fragaria genotypes using AFLP and candidate gene EST markers. Finally, the correlation between specific DNA markers and leaf WLR and RWC and possibility of using association mapping in a small set of Fagaria accessions were tested to create a set of correlated markers to the physiological drought involved traits in Fragaria. The extensive use of F. vesca as a characterized Rosaceae model plant species in this study ensures the benefit of characterization of drought response in other important Rosaceae fruit species, such as almond (Prunus dulcis Mill).

Lettuce is regarded as one of the most important leafy vegetable crops. Despite lettuce being mostly grown in open-field, its greenhouse production is widely increasing. Lettuce growth evolves two distinct stages known as the seedling and head stages. The effect of supplemental lighting (SL) on the lettuce growth was well studied but the lighting requirement during the early stage of lettuce growth and the head development remained unknown. To shed light on the subject, the lettuce’s nutritional quality and growth in response to SL were studied in separate stages of seedling and head development. The experiment was carried out using SL with different daily light integral (DLI) provided by light-emitting diodes (LEDs). Light treatments included supplemental DLI of 8.64, 11.52, 12.96, and 17.28 mol m−2 d−1. The results revealed that the light period was more effective on lettuce biomass increase than the light intensity. Although the SL increased the photosynthetic pigment content of lettuce, its impacts on the two growth stages were not the same. In a way that the chlorophyll a, total chlorophyll, and carotenoid contents decreased under the SL (DLI of 17.28 mol m−2 d−1; light intensity of 300 μmol m−2 s−1 for 16 h) conditions. Increasing DLI caused a significant increase in the nutritional quality of lettuce but the trends of the antioxidants accumulation were not consistent for the seedlings and the mature plants. These findings confirmed that SL improves the lettuce growth and quality, but the optimal lighting requirements may vary depending on the growth stage.

Precision management of medicinal plant production using mechanical systems, processors, and sensors increases productivity, reduces waste, and properly manages production processes. This research developed a precision harvesting unit equipped with an automatic height adjustment system for utilization in harvesting machines to harvest Hyssop at an optimal height. The developed unit consists of a power transmission system (converting rotational motion into reciprocating motion), a harvesting platform (cutter-bar, reel, and conveyor) and a system to control the vertical movement of the head. An ultrasonic sensor was employed to detect the highest part of the plant for control purposes. A central control board and a driver were utilized to generate the control signal, while a stepper motor was installed as the actuator. Harvesting-related variables, including dry matter, essential oil content and yield, leaf-to-stem ratio as well as indices related to conservation agriculture were measured to evaluate the developed precision harvesting unit. Results showed that the unit increased the purity of the harvested plant raw material compared to manual harvesting of Hyssop which is important in extraction of the target substance such as essential oil. Steady-state error of the control system in adjusting the cutter-bar height for optimal height of harvesting Hyssop (T15) in elevation and descension modes was 2%.

Using microorganisms can develop into a promising strategy for increasing photosynthetic activity and greater accumulation of assimilates in crops. This study aimed to evaluate the effects of Rhodopseudomonas palustris on fruit yield and quality of ‘Keitt’ mangoes grown under semi-arid environmental conditions. The experiment was carried out simultaneously in two mango orchards in Petrolina, Pernambuco, Brazil. The study comprised a randomized block design with treatments distributed in 7 treatments, 4 replications, and 3 plants per plot. The treatments consisted of different strategies for applying R. palustris. These treatments were T1) control treatment; T2) 1.43 × 107 CFU/plant via fertigation; T3) 2.85 × 107 CFU/plant via fertigation; T4) 4.27 × 107 CFU/plant via fertigation; T5) 5.70 × 107 CFU/plant via fertigation; T6) 1.43 × 107 CFU/plant via fertigation + 1.43 × 107 CFU/plant via leaf spray; T7) 2.85 × 107 CFU/plant via fertigation + 1.43 × 107 CFU/plant via leaf spray. The treatments were a pplied monthly, totaling seven applications. We evaluated fruit yield (Mg ha-1), longitudinal diameter, ventral diameter and transverse diameter, fruit mass, pulp firmness, pulp percentage, soluble solids (SS), pH, titratable acidity (TA), SS/TA ratio, and dry pulp mass. R. palustris improved mango yield and fruit quality characteristics regarding longitudinal and transversal diameters and the SS/TA ratio. Mango plants treated with R. palustris at 1.43 × 107 CFU/plant via fertigation (T2) produced 10 Mg ha-1 more than the control group, without loss of fruit quality while considering the European market demand.

Bitter fennel (Foeniculum vulgare var. vulgare) is a preferred subspecies in the food and pharmaceutical industries due to its high seed yield and essential oil content. However, traditional populations used by most farmers are not highly productive. To meet demand, high-yielding cultivars are needed. A five-year experiment in Pakdasht, Iran, screened 50 Iranian fennel populations for maturity habit, seed yield, essential oil content, and lifespan. Results revealed three distinctive groups based on maturity habits: early (120 days to seed harvest), medium (175 days), and late (230 days). Lifespan ranged from 3 to 5 years, with early maturities having the shortest lifespan and medium to late maturities having the longest. Populations from dry and hot/cold climates were early maturities with shorter lifespans, while populations from humid and temperate climates were medium to late maturities with longer lifespans. Over the first 3 years, essential oil yields varied among maturity groups. The highest yields were from Population Fasa (early), Meshkin Shahr, and Moqhan (medium), and population Sari (late). Populations with high essential oil yields, like Meshkin Shahr, Moqhan, and Fasa, show potential and require further investigation for potential introduction to farmers.

In this study, we evaluated the effects of selenium nanoparticles on chilling injury and improving the shelf life of Valencia orange (Citrus sinensis) fruit. Treatments included 0.5 and 1 mg L-1 selenium nanoparticles, with three replicates per treatment and six replicates in total. Statistical analyses were performed using SPSS, with data analyzed by one-way ANOVA and mean separations by Duncan’s new multiplerange test. Results showed that samples treated with selenium at 0.5 and 1 mg L-1 significantly decreased lipid peroxidation (55 and 62%, respectively) compared to control samples. Selenium treatments also in creased the activity of antioxidant enzymes, including CAT (twice and four times), peroxidase (2.5 and 4 times), APX (about 0.5 and 2.5 times), and SOD (by 4 and 6 times), with consistent results in DPPH radical scavenging (by 2.5 and 3.5 times) in the orange fruits. Selenium at both concentrations effectively reduced the incidence of chilling injury in Valencia orange fruits during six months of storage at 3 °C. Chilling injury was best reduced at 1 mg L-1. This study proved that selenium can enhance orange fruit quality and increase its tolerance to cold storage conditions, potentially leading to selenium-enriched fruits with health benefits for consumption.