Survey on Phytophthora Species in Aliabad and Gharetapeh Villages from Varamin City of Iran by GIS Software

During the sampling of sub-crop areas in Aliabad and Gharetapehh of Varamin, 181 soil samples collected from the location set by GPS. After baiting and cultured samples on specific medium of the genus Phytophthora, species identified by valid keys and recorded the pollution of the genus Phytophthora in all samples conducted by GIS software. The results confirmed the existence of two species Phytophthora drechsleri and Phytophthora capsici. After searching about infection rate of each samples to the phytophthora by kriging algorithm with GIS software and correlation comparison of kriging map for amount of disease ,the percentage of sand in the soil and ups and downs on earth results showed that the slope of the land, pond areas, and that places with less electrical conductivity were contaminated. Keyword: GIS, Phytophthora, Varamin, Iran


Introduction
Varamin city has long been by produce of numerous agricultural products, especially vegetables considered as the hub of agricultural products in Tehran province.Some of the agriculture products of this city have a global reputation such as cucumbers, tomatoes, eggplants, and melons.This city has provincial and national top scores in various fields of agriculture, so that in crop year 2015 more than 1200 hectares of Varamin lands were under cultivation of cantaloupe (reference).Despite the economic importance of the products of this province and reports of Phytophthora rot, identifying Phytophthora species and major host's distribution areas, seems necessary.
Fungi are important plant pathogens that cause more significant yield losses than bacteria or viruses.In crop plants, fungi cause more economic damage than any other group of microorganisms, with annual losses estimated at more than 200 billion US$ (Lorestani et al., 2013).Damage caused by damping off depending on plant species, fungi species, temperature and precipitation of soil moisture and can be very variable (Ghaderi et al., 2011).Genus Phytophthora has more than 60 species that are the major cause of various disease in many crops, Symptoms such as damping-off, shoot blight, fruit, stem, crown and root rot, can be seen in most cases and leads to death of the host.Cantaloupe damping-off disease first studied in 1944 and in 1965; genus Phytophthora was isolated from infected root of cantaloupe plant in Varamin by Ershad (Ershad et al., 1992).
Phytophthora species as a leading cause various diseases have been identified in a large number of plants that by their attacks on the plant created signs, such as damping-off, shoot blight, fruit, stem, crown and root rot and in most cases leads to death of the host.The role of the environment in this interaction is important because diseases need specific conditions to develop.Temperature and moisture are two of the most important environmental conditions that influence plant diseases.In addition, balanced and adequate soil fertility for any crop reduces plant stress, improves physiological resistance, and decreases the risk of disease .Global Positioning Systems (GPS) and Geographic Information Systems (GIS) technologies can utilized to geospatially reference information from disease forecasting models, disease surveys and then be used to accurately define prescription management zones (Lorestani et al., 2013).transferred to specific culture medium and sub culture was prepared for purification of them.

The Percentage of Polluted Samples
All citrus leaves and amount of patient texture with all apple baiting of healthy texture were transferred for isolated Phytophthora species to selective medium.Then disease percentage in each samples were recorded according to number of baitings that showed fungi phytophthora spp.pollution (Tables 1-2).Since 20 baiting were for each soil samples, 5% pollution were considered for each one after the authenticity of pollution in each baiting to fungus Phytophthora.
After pure isolation of Phytophthora species identification the species based on taxonomic keys of Waterhouse (1963) and Stamps et al. (1990).

GIS
This software and fellowship of Aliabad and Gharetapeh that were prepared from Iranian New Farms from Etka Company of Varamin city were used for recording the results to study degree of distribution and percentage of disease in the areas.
In addition, we can compare and evaluate our own information with information related to amount of sand in the soil of mentioned area.
Raster map was prepared from amount of fungi Phytophtora spp. in soil of mentioned area then its Kriging algorithm was drawn by GIS 9.3.Kriging algorithm related to amount of sand in the soil texture of two areas was taken in Iranian New Farms of Etka company in Varamin city then dependence of two algorithms in each area were studied separately by GIS.

Isolation and Identification
Separated isolations were detected based on available resources such as Stamps et al. (1990), Waterhouse (1970), and Ershad (1992) and existence of two species in names of Phytophthora capsici and Phytophthora drechsleri were confirmed in two areas.

Phytophthora capsici:
The fast growth on agar environment, round colonies with smooth margins without specific structure and downy, hypha had an acute angle to right one, hypha width was 3.5 to 7.5 micrometers, inflammation of hypha and chlamydospor had not seen in any of cultures.Sporangiophores were disorderly and proliferation mode had not been found in them.Sporangia formed a lot on agar and liquid environments.Sporangia were long, non-dropping with large papillae .They can be seen in different shapes such as ellipse, upside-down pear, and oval shapes.Most of sporangia were thinner in base .Their sizes were in 94-32 × 17-44 and in average 32 × 51 and in average length to width ratio were1, 59.Oogons are spherical, colorless and nearly fills Oogonium.Their diameters in average were 28 micrometer and their walls had 1.5-micrometer thickness.Phytophthora drechsleri: Hypha was without transverse wall and its width was between 3-5-6 micrometers, often root inflammations were separate single and separately in hypha and their sizes were varied in 12-21 micrometer.Chlamydospore was not found in any samples, Proliferation mode was visible in all samples.Sporangia were terminal and without papillae and mostly they were seen in shape of upside-down pear or elongated pear.In some Isolations, wall of sporangia were seemed thicker like a thin crescent.Sporangia were formed in huge numbers after putting cannabis on special cultural environment in white glow then putting seeds in distilled water in mentioned conditions.Sporangiophores were a little thinner than hypha and they had same width.They were nondropping, in size of 23-48 × 26-97, in average 32 × 56 micrometer, length to width ratio of them in average were 1.69.Egg wall was plane, its diameter in average was 2.8 micrometer, and diameter of egg was 27 micrometer.

Study of Disease Percentage in Samples
Disease percentage in all detected samples by baiting techniques, purification and identification of invasive fungal in all sampled areas had been recorded by GPS after examining 181 collected samples from Aliabad and Gharetapeh in Varamin city (Tables 1-2).

Discussion
In The results show distribution extent of disease in these two areas are a lot, according to vegetables, one of the main agricultural products in these areas, such as cantaloupe and watermelon, they can provide the way to damage agricultural products due to that resistant cultivars and insensitive hosts are recommended in these areas.
Further studies and comparative amount of sand in soil texture and degree of disease show that amended soil texture can be effective to control disease.In addition, one of the main factors in increasing disease percentage is rugged cultural land because estimated percent disclosed pond places and pits had large amount of pathogen fungi.It seems leveling of agricultural land can be a great help to reduced pathogen damage in these areas. Figure 2009, Sarpele et al. (2009) survey showed Phytophthora species is one of the main disease factors in green houses in Varamin city that results of this survey confirmed Sarpele et al. (2009) survey and it stated detailed results about existence and percentage distribution of mentioned fungi in Aliabad and Gharetapeh in Varamin city.

Table 1 .
The results of the percent of infection rate in the samples relating to Aliabad area

Table 2 .
The results of the percent of infection rate in the samples relating to Gharetapeh area

Table 3 .
The correlation between the percentage of disease and sand in the soil of Gharetapeh and Aliabad areas