شهره زیودار

 Citrus fruits are susceptible to a number of fungal diseases that cause significant losses in the citrus industry in the postharvest stage. Worldwide, diseases have been primarily controlled for many years by the application of conventional fungicides. However, human health risks and environmental contamination associated with chemical residues and the proliferation of resistant strains of the pathogens are major problems associated with the continuous and widespread use of conventional postharvest fungicides. Heat and UV radiation treatments are the most common physical means used to control postharvest diseases of fresh fruits. The aim of this study was to investigate the effects of UV-C radiation and Hot Air Flow (HAF) treatment on decay control and some biochemical properties in Thomson navel oranges at cold storage.

In this experiment, the effects of heat treatments (37 °C for 24 hours), UV radiation (7.98 kJ / m2) and combination treatment (HAF*UV) on the storage life of Thomson oranges were investigated. The statistical model of factorial experiment was in the form of a completely randomized design in which two factors of storage time and treatments were considered. After treatment, the fruits were stored at 5 ° C for 90 days during the storage period, the percentage of decay, fruit weight loss, and some biochemical properties and enzymatic activity were investigated. Statistical analysis of data was performed using SAS software and the mean data were compared using Duncan's multiple range test at a five percent probability level using MSTATC software.

The results showed that radiation and heat treatment effectively reduced fruit rot . the lowest and highest percentage of cumulative rot was observed in the combined treatment with an average of 3.8% and the control treatment with an average of 12.7%, respectively.The control treatment and the combined treatment with the average of 5.68 and 2.94, respectively, had the highest and lowest fruit weight loss. During fruit storage, TSS, TA, TSS/TA and pH increased and TA decreased The amount of ascorbic acid in fruits treated with hot air flow with an average of 35.54 mg per 100 g of fresh material was higher than the control treatment with an average of 30.67 mg per 100 g of fresh material. Antioxidant activity increased at the beginning of the period, however, the treatments did not have a significant effect on inhibiting DPPH radical activity in fruit flesh The amount of total phenol, peroxidase and polyphenol oxidase enzyme activity in fruit flesh under the influence of heat treatment, initially increased with the period, which the enzyme activity decreased with increasing storage time.

The results showed that radiation and heat treatment were effective in controlling post-harvest decay of Thomson oranges. Radiation had no significant effect on the biochemical changes of Thomson Novel orange fruit. According to the evaluated traits, heat and combination treatment succeeded in reducing the rate of rot and increasing the biochemical properties of the fruit during storage, so it can be considered as a suitable practical option.

This study was conducted to investigate the effect of foliar application of volck mineral oil (0, 1, 3 and 5%) on photosynthesis, gas exchanges and physiological traits of two olive cultivars (Manzanilla and Khediri) as split plot based on randomized complete block design with four replications during 2019-2020 in Ahvaz climatic conditions. The results showed that the application of 5% volck oil reduced photosynthesis in Khediri and Manzanilla cultivars by 40 and 52.4% compared to the control treatment in the second week after foliar application and then the photosynthesis rate increased again. In Khediri and Manzanilla cultivars, transpiration rate increased with the use of volck oil in all three concentrations compared to the control, but there was no definite trend. Stomatal conductance was higher in Khediri cultivar than Manzanilla cultivar and the highest stomatal conductance occurred 45 days after treatment. The lowest and highest leaf temperatures were recorded in control and 3% of volck oil treatment with mean temperatures of 29.34 and 32.17 ° C, respectively. In both cultivars, a decrease in radiation use efficiency was recorded in response to volck oil and high percentage of leaf drop (59.05%) was observed in Manzanilla. Therefore, in order to use high doses of volck mineral oil for olive trees, it should be done more cautiously due to the reduction of photosynthesis and increase in leaf temperature in both cultivars and the high rate of leaf drop in Manzanilla cultivar.

Olive (Olea europaea L.) is an evergreen tree and one of the most important products of the horticultural section in Iran due to high nutritional value of its oil and fruits. Adaptation of olive cultivars to the climatic conditions of different regions are not the same. The results of studies showed that special cultivars are recommended for each region. In tropical and subtropical climates with mild winter such as Ahvaz, the chilling requirement of olive trees is not completed. This condition has led to poor and insufficient flowering in some olive cultivars. Mineral oils, including volck oil are one of the most beneficial treatments to complete chilling requirement and bud break in fruit trees. The aim of this study was to investigate the response of two olive cultivars (Manzanilla and khaziri) to the application of volck mineral oil and studying their flowering and biochemical characteristics in Ahvaz condition.

In this experiment, the effect of volck mineral oil spraying [control (water spray), 1, 3, 5 %] on two olive cultivars were investigated. The experimental design was split plot arranged in complete block design with four replications. Measured traits included flowering characteristics such as the number of inflorescences in the branch, flowers in inflorescence, complete flowers, flowering days after treatments, percentage of flower fall, fresh and dry weight of flower and inflorescence. Biochemical properties such as bud carbohydrates and ABA, leaf proline and chlorophyll were measured.

The results showed that foliar application of 3 and 5 % volck oil caused flowering (31.8 and 28.7 days after treatment, respectively) in Manzanilla cultivar. Bud carbohydrate content increased significantly after tree spraying with volck oil in all of three concentrations. The highest content of bud carbohydrates (78.68 mg/g) was obtained in khaziri when treated with 3% volck oil. The use of volck oil was effective in increasing the ABA concentration in Manzanilla cultivar and its effect was as 3 and 5% volck oil (83.1 and 105.4 µg/g, respectively). The amount of proline in both cultivars increased until 60 days after applying three concentrations of volck oil. The levels of chlorophyll a, chlorophyll b and total chlorophyll increased until 30 days after treatment and then were decreased. Volck oil (3%) can be used for flowering of Manzanilla cultivar in climatic conditions of Ahvaz.

Based on the obtained results, it seems that the effect of volck oil on flowering and biochemical traits depends on the type and concentration of mineral oil and type of the cultivar. In the present study, flowering occurred when Manzanilla cultivar treated with mineral volck oil (3 and 5%) and the flowering traits were improved at 3% oil more than other treatments.

The aim of this study was to assess the crop water stress index (CWSI), derived from leaf temperature using infrared thermometer measurements, to investigate the water stress status and irrigation timing of olive trees. Fpr this purpose a regression function was determined between crop water stress index and relative water content of leaf (RWC) and soil water content (SWC). The experimental treatments involved two olive cultivars (Koroneiki and T2) and four water regimes (irrigation of 100, 85, 70 and 55% of crop water requirement). The results showed that the non-water stressed baseline is varied throughout the study period as well as during the day. The daily variations of non-water stressed baseline were mainly due to variations in the intercept of the non-water stressed baseline that can be explained by variations in zenith solar angle. After investigating the relationship between vapor pressure deficit (VPD) and the difference between crop and air temperature (), the equation of Tc-Ta = -0.45 VPD+1.06, r2 = 0.99 was determined for the non-water stressed baseline of the olive trees at 12:30 pm. The effect of irrigation regime on water stress index of Kroneiki and  olive trees was not significant in none of the measurements during the study period. However, crop water stress index was significantly correlated with relative water content (Kroneiki: r2=0.67**, : r2=0.88**) and soil water content (Kroneiki: r2=0.74**, : r2=0.78**). Therefore, the crop water stress index is a good indicator of the water stress status of the Koroneiki and T2 olive trees.

Spectrometric measurements have the potential for fast and non-destructive measurements of plant water stress. The aim of this work was to investigate the ability of several spectral water indices, including water index (WI), normalized spectral water indices 1-5 (NWI 1-5), and normalized water index based on wavelengths in 960 and 940 nm (NWI 960-940) for detection of water stress in olive trees. The experimental treatments involved two olive cultivars (Koroneiki and T2) and four water regimes (100%, 85%, 70%, and 55% of crop water requirement). Results showed that the olive trees in different water supplies 85%, 70%, and 55% of ETc were subjected to soil moisture deficit equal to 11, 15, and 20%, respectively, as compared to soil moisture of control treatment. Because of the high resistance of olive trees to water stress, water reduction at levels of 15, 30, and 45 percent did not have significant effects on spectral indices. However, spectral indices were closely and significantly linear associated with relative water content of the crop leaf (). Among all tested water spectral indices, NWI-2 showed the least consistent associations with relative water content of the leaf (ranging from 1–23% less than the ones in other tested indices). Based on the average amount of spectral indices and relative water content during the study period, NWI4, NWI5, NWI1, WI, NWI960-940, NWI3, and NWI2 showed a stronger relationship with the relative water content of olive leaves, respectively. In conclusion, spectral reflectance indices, WI, NWI 1-5, and NWI 960-940, could be useful for fast and non-destructive estimating of plant water stress.

In order to evaluate the effects of foliar application of potassium sulfate on some quantitative and qualitative characteristics of three olive (Olea europaea L.) cultivars, two split plot field experiments, arranged in complete block designs with three replications, were carried out through 2012–2013 in an orchard located in Ahvaz, Khuzestan province, Iran. Three olive cultivars (Mission, Coronaiki and Dezfuli) and three foliar applications of potassium sulfate (0, 1 and 2 g.L-1) were randomized in main plots and sub-plots respectively. The interaction effect between year and cultivar was significant for fruit fresh weight, dry weight of fruit pulp, stone weight, pulp: stone ratio, oil content (P≤0.01) and fresh weight of pulp (P≤0.05). Also, the interaction effect between year and foliar potassium application was significant for fruit fresh weight, dry and fresh weight of fruit pulp (P≤0.01) and stone weight (P≤0.05). The interaction between cultivar and foliar application of potassium sulfate for fruit fresh weight, dry and fresh weight of fruit pulp was significant at 1% probability level. In addition, interaction effect between year, cultivar and foliar application of potassium sulfate was significant for fruit fresh weight, dry and fresh weight of fruit pulp, oil content of the fruit pulp (% D.W.) at 1% probability level, and other traits at 5% probability level. Thus, it can be concluded that annual variability in the growth environment had an important effect on the parameters studied in this experiment. Dezfuli cultivar had more oil content than other cultivars that could be due to genetic diversity among cultivars for using sources in enhancement oil content and also more compatibility with the environmental conditions in this area. Foliar application of potassium sulfate increased unsaturated fatty acids and decreased saturated fatty acids in Dezfuli and Coronaiki cultivars. The highest content of oleic acid and oleic acid: linoleic acid ratio (60.54 % and 8.38) was found in Coronaiki cultivar with foliar potassium application (2 g.L-1) and the lowest amount in Dezfuli cultivar with control treatment (48.90 % and 1.67). Therefore, year conditions as well as foliar application of potassium sulfate can have a positive impact on ftuit weight, percentage of olive oil and fatty acid composition.