Water is a main factor in agriculture activities and almost 70 percent of world water resources are consumed in agriculture. The present research has been done to investige response of Citrus rootstocks to drought as factorial test based on randomized completely design with three replications. Factors included rootstocks in 10 levels [Poncirus (PT), Troyer citrange (TC),Citrumello (CR),Sour orange (SO),Cleopatra mandarin (CM), Rough Lemon (RF), Bakraii (B), Chang-sha (CH), Machrophylla (M) and Mexican Lime (ML)] and irrigation in two levels [optimum irrigation (fixed in field capacity) and withholding irrigation]. Results showed that drought induced increament of ion leackage percentage in all of the rootstocks and  the root to shoot dry weight ratio in PT, M and B and decrease of leaf water relative content in all of the rootstocks, leaf fresh weight in SO, stem fresh weight in CR, root fresh weight in TC, SO, CR and M, shoot fresh weight in SO and CR, total fresh weight in SO, CR and M, root to shoot fresh weight ratio in TC, CR, M and CM. Therefore, TC, CH and PT had good tolerance to drought because of lower ion leackage in TC, higher water storage in CH leaves and the higher root to shoot dry weight ratio in PT.

Vegetative reactions of six citrus different rootstocks (Swingle citromelo; Troyer citrange; Carizo citrange, C-35; Smooth flat sevill and Gou tou) and their effect on early mature Miyagawa Satsuma mandarin was evaluated during 8 years (2010-2017). Experiment was done in randomized complete block design with 4 replications and 4 trees in each replication. Results showed that after vegetative phase (third year) trees on Gou tou had the least canopy volume and height but in the last three years, trees on C-35 had minimum volume and height. In contrast, trees on Swingle citromelo rootstock had the most canopy volume. The most rootstock trunk cross-sectional area (TCSA) and girth was related to Swingle citromelo and the most mandarin trunk girth and TCSA was on Smooth flat sevill. Results of rootstock and scion affinity showed that in Smooth flat sevill it was more than 1, in citranges it was about 1 and in Swingle and Gou tou it was less than 1. Rootstock TCSA had the most correlation with canopy volume and scion trunk girth had the most correlation with canopy height and width; so these can be used to estimate the canopy volume.

The consumption of inorganic fertilizers in agricultural ecosystems led to the destruction of soil physical, chemical, and biological characteristics and severely affected the quality of the products. Therefore, the application of compost fertilizers in agricultural lands has been widely considered, and it has been mentioned as the best environmental measure. Rootstock plays a crucial role in the growth of citrus trees. Among all the nutrients needed by citrus, nitrogen has a vital role, and a large amount of this macronutrient is supplied in the soil every year. The release of nutrients from organic matter, especially nitrogen, is slower than the nitrogen release from chemical fertilizers. Rootstock affects the photosynthetic capacity of the transplanted cultivar, which is related to the annual carbohydrate redistribution and is a determining factor for vegetative growth and reproductive development. The growth, yield and fruit quality of cultivars are, therefore, strongly regulated by rootstock. In the recent study, the effects of compost and nitrogen fertilizers on common rootstocks in Mazandaran province, including citrange, citrumelo, and sour orange, were investigated. An experiment was conducted as a completely randomized design at Qaemshahr Horticultural Research Station. The treatments included sulfur granular compost (0, 2.5, 5, and 7.5%), produced by Mazandaran Wood and Paper Industries Company, and pure nitrogen (0, 20, 40, and 80 mg kg-1) in the form of ammonium sulfate. Vegetative growth, including plant height, crown diameter, and the number of leaves, were measured. Also, to study the changes in leaf nutrient concentration, leaf samples were collected, in July and the concentration of nutrients in leaf tissue was measured. A randomized complete block design was conducted at Qaemshahr Horticultural Research Station in 2017. The treatments included sulfur granular compost (0, 2.5, 5, and 7.5%), produced by Mazandaran Wood and Paper Industries Company, and pure nitrogen (0, 20, 40, and 80 mg kg-1) in the form of ammonium sulfate. One-year-old seedlings of the same size from citrange, citrumelo, and sour orange were planted in 7- kg pots containing arable soil and the treatments. The applied soil was analyzed, and its physical and chemical properties were determined. Irrigation of all pots until reaching the field capacity (weight method) was performed uniformly for all treatments. At the end of the growth period, vegetative growth parameters, including plant height, crown diameter, and the number of leaves, were measured. Also, to study the changes in leaf nutrient concentration, fully developed leaves samples were collected, in July and the concentration of nutrients was analyzed. Nitrogen was determined by the Kjeldahl method with a sulfuric acid-hydrogen peroxide mixture. Phosphorus by calorimetric, potassium using a flame photometer, and calcium, magnesium, iron, manganese, zinc, and copper were measured using the flame atomic absorption method. Results showed that the highest nitrogen concentrations in citrange and citrumelo seedlings were 2.92 and 2.97% due to 40 and 80 mg kg-1 N and 2.5% compost, respectively. In citrumelo rootstock, plant height increased with enhancing nitrogen application levels at different compost levels. Compost levels did not show a significant increase in citrange height, but the highest height growth was observed at 40 and 80 mg kg-1 nitrogen. In the sour orange rootstock, consumption of high levels of compost and nitrogen significantly reduced plant height. In all three rootstocks, the highest concentrations of potassium were observed in high levels of compost and no nitrogen application. The concentration of iron and zinc in citrumelo leaves increased with increasing compost levels. The trend was different in citrumelo so that consumption of 2.5% compost and 40 mg nitrogen fertilizer showed the highest concentration of leaf iron (151 μg g-1), while the application of 5% compost without nitrogen reduced the concentration of iron to 62.2 μg g-1. Changes in citrange zinc concentration were similar to citrumelo. In sour orange, iron concentration changed limitedly and ranged from 83.8 μg g-1 in 2.5% compost and 20 mg kg-1 nitrogen fertilizer to 61 μg g-1 in control. In this rootstock, the highest concentration of zinc was obtained from no compost application and 40 mg kg-1 nitrogen (28.14 μg g-1), whereas the lowest concentration of iron was observed in control. Citrange seedlings performed better in nutrient uptake than citrumelo and sour orange seedlings. Consumption of 5 and 7.5% levels of compost in sour orange rootstock reduced plant height and crown diameter and caused rosette, led to an increase in the number of leaves. The most effective level of nitrogen in sour oranges was 80 mg kg-1 nitrogen. Application of 80 mg kg-1 nitrogen and 2.5% compost, and 80 mg kg-1 nitrogen and 5% compost led to the highest number of leaves in citrumelo and citrange rootstocks, respectively. According to vegetative growth and concentration of nutrients data, especially from the nitrogen concentration point of view, maximum vegetative growth was obtained in citrumelo rootstock from 2.5% compost and 40 mg kg-1 nitrogen treatment and in citrange and sour orange rootstocks from 2.5% compost and 80 mg kg-1 nitrogen treatment.

It is important to attend the physical and biochemical characteristics of the fruit, especially in newly introduced cultivars that may be unknown to the consumer. Nutritive compounds in fruit are usually influenced by variety, rootstock and post-harvest conditions. In this article, the results related to the evaluation of the fruit quality of three varieties of oranges on two rootstocks have been examined at harvest time and during storage.

Fruit of Thomson Novel, Fukumoto, and Navelate oranges on two rootstocks including Swingle Citrumelo and Citrange C-35 were harvested when TSS/TA reached about 6.5-7. Fruits were evaluated at the harvest time and then stored in cool storage (5oC, RH=85%) for 60 days. The fruit quality were checked on the 30th and 60th days of storage for two years. Evaluated Characteristics included fruit lenght, width, thickness; arithmetic, geometric, equivalent diameter and harmonic means ; fruit aspect ratio, sphericity, surface area, true volume, apparent volume, volume error, density, weight, weight loss, peel thickness, juice percentage, peel color indices (L*, a*, b*, hue angle, chroma and CCI), total soluble solid (TSS), titratable acidity (TA), technological index (TI), total phenol, ascorbic acid, antioxidant capacity and organoleptic evaluation.

The fruit of Navelate orange on Citrumelo rootstock and Fukumoto orange on C-35 rootstock had smaller physical characteristics than Thomson Novel. In all treatments, the shape of the fruit was balanced and without elongation or indentation. The fruit of Navelate on Citrumelo (aspect ratio: 96.96) was slightly elongated. Navelate variety on C-35 produced larger and heavier fruit similarly Thomson fruit. The volume error in Fukumoto and Navelate varieties and on both rootstocks was less than the control. At the time of harvest, the fruit of the Fukumoto had a thicker peel (more than 4 mm) on both rootstocks than the other cultivars. The amount of juice percentage was not significantly different than control at harvest time, but at the end of storage, the fruit of Navelate on the C-35 had the lowest (35.73%) of juice percentage. Fukumoto and Navelate fruits on both rootstocks had higher TI index than Thomson at harvest time. The TSS at harvest time was the lowest (9.22 and 9.78 respectively) only in the fruits of Thomson and Navelate on Citrumelo rootstock. Navelate and Thomson fruits had higher TA on C-35 rootstock. In all treatments, the amount of TA decreased during storage. Fukumoto fruit on C-35 had the highest TSS/TA ratio, which was preserved during storage. The fruit of Navelate had a lower TSS/TA level at the harvest time on both rootstocks (7.12 and 7.5). At the time of harvest, the average ascorbic acid in all three cultivars on C-35 rootstock was higher than the same cultivars on Citrumelo rootstock. The value of a*, hue angle, and CCI of the skin of Navelate orange with a negative value were different from the other cultivars on Citrumelo and C-35 rootstocks (-1.12 and -0.61 respectively). The antioxidant capacity of Fukumoto fruit was 43.99% on Citrumelo and 62.12% on C-35 rootstock at the harvest time. The amount of antioxidant capacity and total phenol increased during storage. The organoleptic evaluation showed that the Fukumoto as Thomson, scored better in relations to peel and pulp appearance, sourness, aroma and taste than the fruit of the same cultivars on the C-35 rootstock. Navelate fruit produced higher score in terms of taste and sweetness (7) on Citrumelo rootstock than C-35 (6) rootstock.

Based on the TSS/TA ratio, it was determined that Fukumoto and Navelate oranges are early and late ripening respectively. Citrumelo rootstock increased late ripening in Navelate fruit and contrary C-35 rootstock increased early ripening in Fukumoto fruit. According to the a* and CCI indices, the Navelate fruits did not have suitable coloring at the time of harvest, and Citrumelo rootstock delayed the color change of the fruit skin. In general, the organoleptic characteristics of the fruit on C-35 were better than Citrumelo. Finally, it seems that the combination of Navelate/C-35 is more suitable than Navelate/Citrumelo. Fukumoto/C-35 combination is suitable for having early ripening fruit.

In this research, responses of some citrus rootstocks to active and equivalent calcium carbonate in the soils of eastern Mazandaran were evaluated by a factorial experiment in randomized complete block design. The results showed that Swingle citrumello and Sour orange, common rootstock of the region, had maximum and minimum dry weight. Also, average rootstocks chlorosis degree in these soils showed that Swingle citromello had the highest chlorosis degree and C-35, Carizo citrange, Gou tou, Troyer citrange, Smooth flat sevile, and Sour orange ranked after Citromello, respectively. According to the results, with increasing soil equivalent and active calcium carbonate, the average leaf active Fe of different rootstocks decreased. On average, the percentage of total iron in the form of active iron in the leaves was much higher than roots. In contrast, the average of total iron concentration in roots was several times more than that of leaves. Besides, by increasing calcium carbonate, the percent of leaf total iron in active form decreased, but unlike the leaves, the percentage of active iron in roots increased. Also, increase in soil active calcium carbonate did not have any effect on leaf active iron level of Sour orange and Smooth flat sevile. In contrast, leaf active Fe in Swingle citromello, Carrizo citrange, Troyer citrang, C-35, and Guo tou decreased. Therefore, according to leaf chlorosis degree index and trend of reducing leaf active Fe level per unit of active calcium carbonate, Sour orange, and Smooth flat sevile were the most tolerant, while Swingle citromello was the most sensitive rootstock to soil carbonate calcium, followed by Gou tou, Carizo citrange, Troyer citrange and C-35, respectively.

Root systems in citrus trees develop from rootstocks. They have, thus, direct effects on water and nutrient uptake and translocation. The present study was conducted to evaluate the effects of three rootstocks common in northern Iran (i.e., sour orange, Swingle citrumelo, and Troyer citrange) on the nutrient uptake, translocation, and accumulation (NAI) as well as their translocation indices (NTI). For this purpose, one-year old seedlings of sour orange, Swingle citrumelo, and Troyer citrange were cultivated in a loamy soil under glasshouse conditions. After six months, the seedlings were harvested to measure their dry weights as well as their leaf, stem, and root concentrations of phosphorus, potassium, calcium, iron, manganese, zinc, and copper. Also, the rootstocks investigated were discriminated based on their nutrient accumulation and translocation indices as determined by factor analysis. Results showed the superiority of Troyer citrange in terms of phosphorus and iron uptake; citrumelo in terms of potassium and copper uptake; and common sour orange in terms of calcium and manganese uptake. The order recorded for the rootstocks in terms of their nutrient accumulation indices was sour orange>Troyer citrange~Swingle citrumelo. It was also found that the nutrient translocation indices of the three citrus rootstocks decreased in the following order: Swingle citrumelo > Troyer citrange > sour orange. Clearly, the citrus rootstocks investigated exhibited differential nutritional behaviors and different capacities with respect to utilizing plant nutrient elements.

In this study, the effects of six citrus rootstocks: Swingle citromelo; Troyer citrange; Carizo citrange, C-35 citrange; Smooth flat sevill and Gou tou) on reproductive reactions of Miyagawa Satsuma mandarin was investigated during 5 years (2013-2017). Experiment was done in randomized complete block design with 96 trees. Results showed that trees on Swingle citromelo at the beginning of fruiting phase (2013 and 2014) was more productive (58 and 48 kg/tree respectively) than other rootstocks and they had the most annual mean yield (52 kg/tree), cumulative yield during 5 years (261 kg/tree) and minimum alternate bearing index (22.1%), statistically. Also, cold tolerance in this rootstock was more than others due to maintaining the flower and fruit and high final yield in the year after the frost (2014). Annual mean yield and cumulative yield during five years on Citranges (Troyer, Carizo and C-35) and Smooth flat sevill was statistically similar. But, the highest yield efficiency was obtained on C-35 (6.72 kg/m3). Fruits on Swingle citromelo, were more spherical (length/width: 0.953) and juicy (46.22%), on Carizo were more oblate (length/width: 0.939) and thinned peel (2.21 mm) and on C-35 were heavier (150.2 g) and more premature (harvest index: 11.21) than fruits on other rootstocks. Gou tou significantly increased the thickness of the peel (2.83 mm), reduced fruit juice (41.65%) and extended fruit ripening time (harvest index: 8.52). Also, trees on Gou tou had the highest alternate bearing index (42.4%) during five years.

A general surveys were conducted in Mazandaran citrus groves for the presence of Phytophthora species causing citrus gummosis. Soil samples and infected citrus tissues were collected and assayed using baiting and selective medium. Phytophthora citrophthora and P. nicotianae were detected in all of the citrus orchards and their distribution was mapped. The soil population of each species was also determined. Eighty two and 86% of the orchards were infested respectively with P. citrophthora and P. nicotianae with average over 10 propagules /g soil.The virulence of five isolates of each species to root of 1-year-old citrange, citromelo, Shahsavar orange, and sweet lime was examined. Data analysis of fresh weight of root and stem, and disease index in citrange revealed three groups including control, P. nicotianae, and P. citrophthora isolates, which the that third group was significantly more virulent than the second group. Data analysis of fresh weight of root and stem in citromelo and Shahsavar orange did not show significant differences between P. nicotianae, and P. citrophthora isolates. On the basis of disease index data of citromelo and Shahsavar orange, P. citrophthora isolates were more virulent than P. nicotianae isolates. Data analysis of fresh weight of root and stem and disease index in sweet lime did not show significant differences between P. nicotianae, and P. citrophthora isolates.

Based on the valuable antioxidant activity of citrus fruits, in present study the effect of rootstock (sour orange and citromelo) and fruit tissues (pulp and peel) on total titrtable acid, vitamin C content, total phenols and flavonoids, antioxidant activity as well as the content of hesperidin and naringin of thampson novel and page mandarin was studied. The experiment was conducted as a factorial assay based on a randomized complete blocks with four replications. According to the obtained results, the amount of titrtable acid of thampson novel fruit was higher than that of page mandarin. In comparison with sour orange both fruits produced a higher titrable acid with citromelo. The content of vitamin C of fruits grafted on sour orange was higher than that of citromelo, in which shows a higher nutritional quality of fruit. Antioxidant activity and the content of total phenol, total flavonoid, and hesperidin of thampson novel fruits were significantly higher than that of page mandarin. Contrary to hesperidin, between thampson novel orange and page mandarin the content of naringin of page mandarin was at the highest level. In compare to the sour orange, fruits on citromelo showed a higher antioxidant activity, flavonoid and hesperidin content. On the other hand, results showed no difference on the amount of total phenol and naringin between two different rootstocks. Results showed that the accumulation of measured antioxidant compounds of peel is noticeable. Finaly based on the obtained results it can be concluded that although the concentration of pharmaceutical and nutritional compounds is strongly related to the genotype, it seems that a higher quality and quantity of such compound could be achieved using a suitable rootstock.

In this research، catalase activity and leaf Chlorophyll stability of Satsuma mandarin on some citrus rootstocks under waterlogging condition were studied. Experiment was conducted as factorial with randomized complete blocks and 6 replications. The first factor، include 7 soils from East Mazandaran and the second factor included 7 different citrus rootstocks: 1. Sour orange، 2. Swingle citromelo، 3. Carizo citrange، 4. Troyer citrange، 5. C35، 6. Smooth flat seville and 7. Gou tou. Seedlings were kept under continuous waterlogging stress condition in the second year of growth. The results showed that catalase activity and stability index of chlorophyll were significantly affected by waterlogging stress. Catalase activity increased under waterlogging stress and its amount in C35 was more than other rootstocks. Interaction of soil and rootstock also had significant effect on catalase activity. Also، rootstocks and different soils had significant differences in changes trend of the stability index of chlorophyll. Average of chlorophyll stability index in total waterlogging period showed that Gou tou، C35 and Swingle citromello had the highest chlorophyll stability; Sour orange had the least amount. Chlorophyll stability index of scion on different rootstocks in different soils indicated the different tolerance of rootstocks in various soils to waterlogging stress.