In the present study propagation of three clonal rootstocks of stone fruits including of VPK1, St-Julien A and GF677 were evaluated with in vitro culture. Explants of apical and lateral buds of rootstocks were disinfected and cultured in modified MS, WPM and Knop media. VPK1 rootstock produced the highest plantlet number and length in WPM and modified MS media. Two other rootstocks produced the highest of plantlet number and length in modified MS medium. VPK1 rootstock in WPM and Knop media and St-Julien A in Knop medium showed chlorosis symptoms, thus combination of plant growth regulators were evaluated in modified MS medium. St-Julien A had the highest proliferation in MS3 medium (containing 1 mgl-1 BAP and 0.5 mgl-1 NAA). Optimum proliferation in GF677 and VPK1 rootstocks were obtained in MS1 medium (containing 0.6 mgl-1 BAP and 0.01 mgl-1 NAA). Evaluating three rootstocks, the highest plantlet length were produced in MS1 medium. VPK1 produced callus in MS2 (containing 0.8 mgl-1 BAP and 0.1 mgl-1 NAA) and MS3 media. Increasing concentration of plant growth regulators led to vitrification and callus production of shoots in GF677 rootstock. St-Julien A and VPK1 rootstocks in medium containing 1 mgl-1 NAA and GF677 rootstock in medium containing 1 mgl-1 IBA produced the highest root length. In rooting medium proliferation of rootstocks were observed. Effect of clonal rootstocks on mean root number was not significant. Rooty rootstocks were transferred to peat and perlite medium in acclimization room.

Almond witches' broom (AlmWB) is an economically important disease in Iran and Lebanon. Graft inoculation was used to study the reaction of stone fruits other than almond to AlmWB phytoplasma. Two-year old seedlings of bitter almond (Prunus scoparia), peach (P. persica), (Cultivars E1berta, zaferani and Shaftalou) nectarine (P. persica var. nusipersica), apricot (P. armeniaca,), cherry (P. avium), plum (P. salicina ), prune (P. domestica) and soure cherry (P. cerasus) were obtained from a local nursery in an AlmWB disease free area in Isfahan. The absence of phytoplasma in provided seedlings was confirmed by nested- PCR using P1/P7 followed by R16F2n/R16R2 primer pairs. Seedlings of each cultivar were grafting inoculated (3 scions per seedling) with Candidatus Phytoplasma phoenicium infected shoots of an infected almond tree. Five seedlings of each cultivar were grafted and one remained as control.

In recent years, symptoms of virus diseases on stone fruits have been observed in wide range in Golestan province. In order to study the important viruses on stone fruits, cherry, plum, nectarine, peach and apricot trees with symptoms such as mosaic, chlorosis, ring spot, shot hole, pale margins in leaves and dwarf in trees, Sampling was done during 2005. Putative infected plants were tested by DAS-ELISA kits respected to PNRSV (Prunus necrotic ring spot virus), PPV (Plum pox virus), PDV (Prune dwarf virus), CLRV (Cherry leaf roll virus) and ArMV (Arabis mosaic virus). Positive results were obtained for PNRSV in peach, nectarine and plum, but not in cherry and apricot. The most infected regions were Aliabad and Gonbad with the highest infection rate in foreign cultivar peach (6.55%) and red gold nectarine (3.22%).

This study investigated the export status of stone fruits in Iran during 1997 to 2010. Export trends and revealed comparative advantage of indices, namely, Revealed Comparative Advantage (RCA), Revealed Symmetric Comparative Advantage (RSCA), and Relative Export Advantage (RXA) as well as Trade Mapping (TM) were investigated for cherries, plums, peaches, and apricots. Target markets for these products were ranked using numerical taxonomies. The results showed that Iran had export's comparative advantage for stone fruits only in 2007 and 2010. But, this index had a positive growth for the stone fruits in those years, indicating an increasing trend in the export status of these products. Trade mapping analysis indicates that although the export market for these products has declined during the period studied, Iran has taken a greater share of the market and is among the winner groups. The principal export markets in decreasing order were found to be Germany, The UK, France, Italy, the Netherlands, Russia, Saudi Arabia, Bahrain, Switzerland, the UAE, and Afghanistan.

In this study propagation of three promising genotypes of stone fruit hybrids including two genotypes of apricot and plum hybrids (Hs519 and Hs303) and one genotype of plum and almond hybrid (Hs725) were evaluated via in vitro method. Explants of apical and lateral buds of rootstocks were disinfected and placed in modified MS, WPM and Knop media with combinations of 0.6 mgl-1 BAP and 0.01 mgl-1 NAA. The results showed that modified MS medium was qualitatively the best medium for all rootstocks, thus different concentrations of plant growth regulators combinations were evaluated in the modified MS medium.0.6 mgl-1 BAP and 0.01 mgl-1 NAA was the most economical combination of plant growth regulators that produced the highest appropriate number and length of micro-cuttings. There was no significant difference between hybrids in proliferation. Hs725 and Hs519 produced micro-cuttings with a mean of 3.092 and 3.037cm, respectively. Hs519 produced callus in media with higher concentrations of NAA and BAP, and Hs725 showed vitrification in similar media. Optimal rooting number (seven) and rooting percentage (63%) were obtained in Hs725 in media culture containing 1 mgl-1 IBA. In this media culture, the highest root length of 9.33 cm was obtained in Hs725. In general, less concentrations of these plant growth regulators led to better proliferation of these promising rootstocks.

Iran is one of the leading countries in the world in production of many horticultural commodities such as pistachios, walnuts, almonds, apricots, apples, dates, grapes and others. In recent years, the areas under horticultural crops have increased, mainly due to high exchange rate and income as well as improvement in water consumption efficiency, the possibility of export and increasing demand. There is also a possibility of their sustainable development and production in the future. On the other hand, as the world's population grows, the need for food is increasing at an alarming rate. Using the latest statistics published by the Ministry of Agriculture Jihad and other sources, the present status of the horticultural products of each sub-sector of pomology in the years 2012 to 2018 were examined. From temperate zone fruits apple, pear, cherry, peach and apricot,from nut fruits pistachio, almond, walnut and hazelnut, from tropical and subtropical fruits dates and citrus, and from small fruits grapes and strawberries were selected. Considering that the coefficient of selfreliance of horticultural products, except for a small number of tropical fruits, is 100%, in this article, after presenting the statistics, the challenges of the current situation of pomology in the country are analyzed and approaches to overcome the problems of this sector of horticulture are suggested.

Plum pox virus (PPV), the causal agent of Sharka disease, belongs to the genus Potyvirus in the family Potyviridae and has been reported from some regions of Iran. Surveys were conducted to determine the incidence of the virus in Khorasan Razavi province in 2010 and 2011 and 553 samples of stone fruit trees were collected and tested by DAS-ELISA. In this method 12 samples were infected with PPV. RT-PCR with specific primers amplified 467bp band in 3 samples. DNA fragment of Kadkan region was sequenced after purification from gel. The determined sequence of IRN-KDN isolate were compared with previously reported 29 PPV isolates, using ClustalW2. In phylogenetic analyses based on ClustalW multiple alignment and MEGA 5.1, IRN KDN displayed the highest (98% and 96%) identity with two Japanese isolates and the lowest (95% and 90%) identity with isolate of Slovakia at nucleotide and amino acid sequence levels, respectively.

The phenotypic characteristics, electrophoretic pattern of cell proteins and rep- PCR generated DNA fingerprints of Pseudomonas syringae pv. syringae (Pss) strains causing sugarcane red streak disease were compared with those inciting canker on stone fruit trees, blight of wheat and leaf spot in sleepy mallow. The Pss strains from sugarcane were very similar in phenotypic characteristics but varied in the rate or level of formation of levan, syringomycin and in hydrolysis of Tween 80. The electrophoretic pattern of cell proteins of the strains causing red streak were similar although not identical to each other but differed markedly from those of the other groups. The protein patterns of the strains from stone fruits and wheat were indistinguishable. The groups of strains were best differentiated by their rep-PCR fingerprintins. The ERIC- and BOX-PCR fingerprints of the strains from sugarcane were distinct from those of the other groups. The results indicate that the Pss strains isolated from sugarcane with red streak symptom constitute a group genotypically distinct from those inciting canker on stone fruit trees, blight of wheat and leaf spot on sleepy mallow plants.