International Journal of Horticultural Science and Technology
Volume:5 Issue: 2, Summer - Autumn 2018

In micropropagation of lily, preferably bulblets should be produced: Because bulblets are compact and robust, they are much easier to handle and to plant in soil than shoots. In this review, the various factors that determine bulblet growth in vitro are discussed. Gibberellins, jasmonates (JA) and abscisic acid (ABA) are the major identified plant growth regulators (PGRs) for storage organ formation. They also play a major role in lily bulblet growth in vitro. Growth conditions such as temperature and light (quantity and quality) strongly affect lily bulblet growth in tissue culture. Moderate abiotic stresses are introduced as new tool to improve storage organ formation in vitro. The amounts of endogenous carbohydrates (starch) in the explant and exogenous carbohydrates in the medium (sucrose) influence bulblet growth in vitro. It is also discussed how compounds present in the medium or in the scale-explants are translocated to the regenerating bulblet.

Experiments were conducted to evaluate the response of different originated (the same mother plants with different growers from different cities in Ethiopia) cut rose flowers to various relative humidity (RH) and recut (recut and non-recut). Three different experiments (E1, E2 and E3) using three RH (60, 75 and 90%) and three Ethiopian growing areas (Fleur, Liki and Longonot) with 10 replications were designed. Cut rose flowers from three growing area were recut to 5 cm and placed in 60, 75 and 90% RH as a commercial supply chain. Rose flowers without any recut were selected as control. Mean comparison in three experiments revealed that by increasing storage time in cold room, flower vase life significantly decreased. 75% RH produced the highest flower vase life compared to 60 and 90% RHs. However, mean comparisons showed that cut rose flowers originated from Liki growers significantly had the highest vase life compared to others which followed by Longonot and Fleur ones. The results revealed that 5 cm cut the end of flower stem significantly increased flower vase life compared to control. Mean comparison of bacterial populations in commercial supplies of the three experiments, declared the highest amount of bacteria in E1 than the other experiments. Cut rose flowers originated from Liki growers had the highest bacterial populations at the bottom part of the stem compared to the other growers. The results also showed that the end part of stems contain more bacterial agent compared to upper parts.

At present, the fruit picking in most countries still largely relies on manual operation. Manual fruit picking can protect the fruits from damage during the operation process. However, it is time-consuming and labor-intensive, and poses a potential safety risk to the workers while working at heights not reachable. Therefore, a variety of fruit picking machines and platforms have been developed and incorporated into fruit production to improve the fruit picking efficiency. However, they are very costly in manufacturing and frequently cause damages to fruit during the fruit picking process. Recently various relatively simple mechanical fruit picking devices have been designed and developed as an alternative for these automatic fruit-picking systems to reduce the manufacturing costs. These devices have been used in fruit production. However, they still have some shortcomings such as poor portability and complex operation. They also lack mechanisms sufficient to avoid damages to fruit to ensure fruit appearance and quality.This study was to invent a portable and convenient mechanical tool that could be used in combination with manual operation for fruit picking. A portable scissors-type fruit picking device has been developed, which has two hinged levers designed to drive the closure of the shear blades at the top of fruit picking bowl to cut the fruit pedicel, achieving rapid and safe fruit picking. The portable scissors-type fruit picking device invented here is an innovation, with a purely mechanical design that has the advantages of ingenious design, simple structure, good portability, ease of operation, and low costs of use. This device is suitable for large-scale application in the field of fruit picking in many countries.

Fig (Ficus carica L.) is a perishable fruit and it needs to use new techniques in order to increase shelf life of this product. In present study, atmospheric cold plasma as a non-thermal treatment was utilized for preserving fresh fig quality. Dielectric barrier discharge plasma was applied to fruits in two steps. Durations of first treatments were 1 and 5 minutes. Based on this step results, main experiments were conducted for 30, 90 and 180s and cold plasma was applied to packed and unpacked fig samples. Quality was sensory evaluated in terms of color, texture, odor, appearance and overall acceptance. Firmness, color indices (L*, a* and b*),, total soluble solids and pH were also determined. Subjective measurements showed significant shelf life improvement of treated figs compared to control samples while objective quality attributes were not changed except pH and a* which are not undesired. Direct application of plasma for 90 s and in-package treatment for 30 s were suggested for further investigation and considering the practical aspects, pulsed plasma processing of packed figs for 30 s is recommended. It is concluded that atmospheric cold plasma has a potential for prolonging the shelf life of fresh fig fruits.

Several methods have been proposed for recommendation of phosphorus fertilizers. Each of them only examines the concentration of phosphorus in the soil or plant, while none of them investigates the correlation between phosphorus concentrations in the soil and plant. In this study, a method called "integrated plant and soil system" (IPSS) is proposed to describe phosphorus fertilizer. In this system, for recommendation of phosphorus, the correlation between this element in soil and plant was used. For this purpose, 39 Washington Navel Orange orchards were selected in Jahrom region and from each orchard three trees were chosen. Samples were taken from soil and plants during two consecutive years and their phosphorus was measured. Orchards were divided into two categories, first group high-yield orchards and another includes all orchards. The correlation was run between soil properties and phosphorus of plant organs with the phosphorus of soil saturation extract samples. Factors were selected that shown significant correlation with the phosphorus of soil saturated extract, and multivariate regression was established between them. The results showed a significant correlation between phosphorus of plant organs and soil samples, and the highest correlation was observed between fruit phosphorus and phosphorus of soil saturation extract. Moreover, there was a significant correlation between phosphorus of plant organs, and the highest correlation was observed between fruit phosphorus with other plant organs. A equation was also obtained for each of the two orchard groups, these two equations can calculate the amount of phosphorus required for orange orchards.

The experiment was carried out during 2015-2016, with the aim of investigating the effects of scion cultivar, rootstock age and hormonal treatments on the success of walnut minigrafting. Analysis of results showed that all studied factors were effective on graft-take and survival of minigrafted walnuts and other growth traits of the scions. The highest graft-take was observed on one-year-old rootstocks in hormonal treatments of 20 mg/L BA + 12.5 mg/L IBA for ‘Jamal’ and 80 mg/L BA + 50 mg/L IBA for ‘Chandler’. The highest survival rate was observed on one-year-old rootstocks in control treatment and the lowest was on two-year-old rootstocks in hormonal treatment of 80 mg/L BA + 50 mg/L IBA. The highest growth rate of scion belonged to the scions of ‘Jamal’ on one-year-old rootstocks in hormonal treatment of 20 mg/L BA + 12.5 mg/L IBA and the lowest was in scions of ‘Chandler’ on two-year-old rootstocks in hormonal treatments of 20 mg/L BA + 12.5 mg/L IBA and 80 mg/L BA + 50 mg/L IBA. In addition, diameter of the graft union on two-year-old rootstocks was more than on one-year-old ones. Histological studies showed that increase in the diameter of the graft unit on two-year-old rootstocks was due to dead and necrotic tissues at the upper parts of it which acted as a barrier against passage of water and minerals from the rootstock to the scion and reduced the growth of the scion on two-year-old rootstocks.

Because of sexual propagation of Mexican lime in southern regions of Iran, there are many lime accessions (lime biotypes) in Mexican lime gardens in which appear some variation in fruit and tree shape. However, most of these accessions are susceptible to witches broom disease of lime (WBDL). Persian lime (C. latifolia Tanaka) is a triploid WBDL-tolerant species. Considerable number of un-described lime biotypes have been cultivated by farmers as Persian lime with no documented evidence related to their origin and genetic background. To unveil systematic modality of the lime accessions, we investigated 18 lime accessions collected from Fars, Hormozgan and Mazandaran provinces (Iran) using flow cytometry (FCM) approach, morphological characteristics, ISSR and SSR markers in 2016. The results of FCM revealed that 14 out of 18 lime accessions were triploid. Triploid accessions showed higher leaf dimension values together with lower stomata and secretory sacs density compared with diploid accessions. Application of SSR markers confirmed the obtained results of ploidy level determination using FCM and morphological analysis. Results of morphological and ISSR markers demonstrated that four out of 18 accessions were different from others and it was in correspondence with the results of FCM. SSR results also grouped the accessions in line of FCM. In conclusion, it has been shown that IFJKh, Cucumber-shaped lime and IFJKMes accessions, are diploid and their cultivation is not recommended in the infected regions to WBDL phytoplasma.

In order to evaluate the effect of plant growth regulators on sex determination and yield, an experiment was conducted by spraying different hormonal combinations on medicinal pumpkin. Experimental treatments were included different concentrations of NAA (25, 75, 100, 125 mg/l), paclobutrazol (50, 100, 200 and 300 mg/l) and combination of growth regulators (NAA 25 mg/l + PBZ 50 mg/l), (NAA 75 mg/l + PBZ 100 mg/l), (NAA 100 mg/l + PBZ 200 mg/l), (NAA 125 mg/l + PBZ 300 mg/l), and control (no application of growth regulators). Growth regulators were applied on the plants by spraying at the –two-leaf and four-leaf stages. Results showed that spraying paclobutrazol and NAA caused increase in number of female flowers, fruits per plant, seeds per fruits, 1000 seed weight and seed yield per hectare, but the number of male flowers and ratio of male to female flowers were decreased compared to their values in control plants. The highest fresh and dried seed yield of pumpkin seed was obtained with 50 mg/l paclobutrazol.

To investigate the positive effects of salicylic acid (SA) on morphological and biochemical traits of salinity stress-imposed winter jasmine, an experiment was conducted in a research greenhouse. The experiment was conducted using a factorial experiment based on completely randomized design with four levels of salinity stress (2, 4, 6, and 8 dS.m-1) as the first factor and different levels of SA plant hormone (control, 181 and 362 μM) as the second factor in three replications. The results showed that spraying SA on winter jasmine plants, significantly improved all studied traits such as plant height, internode distance, fresh and dry weights, flower number, flower diameter, content of protein, POD and SOD enzyme activities. The positive effects of SA was concentration dependent. Salinity stress increased the activity of peroxidase (POD) and superoxide dismutase (SOD) enzymes compared to 2 dS.m-1 salt treatment. The highest enzymatic activities ​​were observed at 8 dS m-1. In general, according to the obtained results, it can be concluded that foliar application of SA on the plants, has the potential to reduce the negative effects of salinity stress on winter jasmine.

Light is an effective factor in cell suspension culture and must be controlled for optimizing cell growth. Growth of anthocyanin producing suspension cells of a red-fleshed genotype of apple (RFA) was assessed in response to blue diode laser (BDL) and red He Ne (RHNL) laser. The suspension cells in L-shaped test tubes were exposed to short-term laser radiation for 20 min in a rotary shaker. The fresh cell weight (FCW), dry cell weight (DCW), cell volume after sedimentation (CVS), cell number (CN) and cell viability (CV) as criteria of cell growth were recorded at 0, 4, 8, 12 days during cell culture. The cell growth was negatively affected in response to BDL and RHNL compared to control and darkness, respectively. The FCW and DCW was enhanced by BDL whereas were not affected by RHNL. Also, only 30.4 mWcm-2 intensity of BDL could increase CVS in RFA cells. Changes in CN were not displayed by RHNL and BDL. BDL more than RHNL decreased CV. Cell death rates observed due to BDL and RHNL were 40.42% and 33.67%, respectively. All these results showed that these lasers had diverse effects on FRA cell growth, however, these cells were more sensitive to BDL than RHNL especially in higher intensities, presumably because of its damage to cell membrane leading to cell death.

In order to evaluate the effects of sowing date and intra rows spacing on yield, yield components and some phytochemical characteristics in Roselle, a field experiment was conducted as a split plot layout based on randomized complete block design with three replications in 2013 and 2014 growing seasons. Five sowing dates were considered as the main plots (11th and 30th of March, 14th of April, 5th and 22th of May) and three intra rows spacing were considered as the subplots (50, 75 and 100 cm). The results indicated that delayed sowing date significantly reduced plant height, number of bolls, number of branches per plant, calyx dry weight, calyx yield, seed yield and biomass yield. Plant height, calyx yield, seed yield and biomass yield were increased by reducing intra rows spacing. Reducing the intra rows spacing caused decrease in number of branches, number of bolls, seed weight, calyx and plant dry weights. Anthocyanin and vitamin C were significantly reduced by delaying in sowing date. Although sowing dates had no significant effect on total phenol but antioxidants were influenced by sowing date. Furthermore, intra rows spacing did not caused any significant effect on phytochemical traits of Roselle. Based on the obtained results, it seems sowing hibiscus tea in the late of March to mid-May and 50 cm intra rows spacing, under hot and dry climate condition would be suitable for increase the final yield of Roselle.

Hypoxia is a potential threat to various horticultural cropsin lands prone to flooding. Citrus is mostly known as a sub-tropical crop that is often exposed to environmental stresses. In order to evaluate response of six different citrus genotypes, including sour orange, rough lemon, Trifoliate orange, Troyer citrange and two local genotypes labeled; CRC1 and CRC2 to flooding conditions, an experiment was carried out in factorial experiment based on a completely randomized design with two treatments including flooded and control plants and three replications. Flooding stress significantly decreased leaf chlorophyll content, and plant total fresh and dry weights (P≤ 0.05). Flooding caused a significant increase in foliar concentration of proline in CRC1 and CRC2 (P≤ 0.05). Guaiacol peroxidase activity was significantly increased in Trifoliate orange. CRC2 and sour orange showed a significant increase in superoxide dismutase activity (P≤ 0.05). The longest survival period in continuous flooding condition was observed in Troyer citrange and Trifoliate orange (more than 60 days); while sour orange was the most sensitive genotype (less than 30 days). The best thriving genotype at the end of recovery period was Troyer citrange, while sour orange showed the least ability to re-establish. The results suggest that among the studied genotypes, Troyer citrange and Trifoliate orange are able to resist for longer periods of flooding exposure. Troyer citrange had the highest capacity to re-establish after being flooded to their critical surviving point. Furthermore, CRC2 tolerated anoxic condition and recovered more successfully than the other sensitive genotypes.