The required capital and liquidity for agricultural production are always a limiting factor in Iranian agriculture. Since, income is a combination of production and product price, one of the major problems of the country's pistachio industry is the high yield fluctuations and high price fluctuations. In the present study, the mean and yield fluctuations of four pistachio commercial cultivars (Kaleh-Ghoochi, Ahmad-Aghaei, Akbari, and Owhadi) were evaluated in the Anar and Rafsanjan orchards in Kerman province. The information used in this study was collected through a questionnaire from farmers. The orchards were selected by multi-stage random method. From the total number of villages in the two regions, some sites were selected based on random. Then, some farmers were selected randomly. By referring to the selected farmers, an orchard was selected from each cultivar. The number of studied orchards was 100 forms in each cultivar. To measure the yield per hectare, the amount of actual product that had achieved in the last six years. Finally, the mean and yield fluctuations of 4 pistachio commercial cultivars were analyzed. The results showed that the studied cultivars had a significant difference in the yield, profit net and coefficient variation at a probability level of 5%. The results indicated that the Ahmad-Aghaei cultivar was the best in average yield (1758.7 kg ha-1) and net profit per hectare (292530201 Rials ha-1) and then Akbari cultivar. However, performance fluctuations in the Owhadi cultivar (53.06%) was lower than the other three cultivars. Base on the results, the Kaleh-Ghoochi cultivar was minimum in average yield (1073.6 kg ha-1) and production fluctuations (73.14%) than the others. Therefore, if the aim is to minimize the income fluctuations of pistachio farmers, depending on the region, one of Ahmad-Aghaei or Akbari cultivars should be planted. It can be concluded that among commercial cultivars, prioritization and justification for planting and propagation were Ahmad-Aghaei, Akbari, Owhadi and Kaleh-Ghoochi, respectively. Manuscript profile

Drought is one of the main important adverse environmental events, certainly has an impact on plant growth and development. Pistachio is cultivated in areas where soil water deficits and salinity conditions are higher than normal. In most orchards, deficit irrigation is a common practice. There is only limited understanding of the physiological mechanisms pistachio uses to survive in drought. Many adaptive strategies have been developed in plants for dealing with water stress. The objective of the present study was to evaluate the effect of drought stress on the photosynthetic, physiological and biochemical parameters in one-year-old seedlings of 12 pistachio hybrids. Therefore, a greenhouse experiment was carried out to assess the effects of two drought stress treatments (drought stress and full-irrigation) for 40 days with a subsequent two weeks’ recovery period and several parameters (pigments (total chlorophyll, anthocyanins and carotenoids), internal CO2 concentration (Ci), chloride (Cl-) ions and fluorescence parameter) were evaluated at four different times (beginning, middle and end of stress and then recovery). After the end of the stress period, the seedlings were irrigated for two weeks. Results revealed that the drought stress treatments led to a change in the studied parameters and the mechanism of drought tolerance was variable at different times. Pistacia atlantica hybrid, P. vera “Sarakhs” and P. vera “Shasti” hybrid rootstocks had the highest water use efficiency; P. vera “Sarakhs” hybrid, P. vera “Khanjari” hybrid and P. vera “Badami” hybrid had the highest Cl- and mesophyll efficiency. P. atlantica and P. vera “Khanjari” had the highest anthocyanins and carotenoids. P. vera “Shasti”, P. vera “badami”, P. mutica and P. mutica hybrid rootstocks have been able to withstand drought stress by increasing the amount of K+ ion and maintaining gas exchanges. The results also showed that the response of the rootstocks to rehydration was different. Seedlings that recovered well after rehydration had a higher tolerance threshold. The “Khanjari” cultivar was recovered better than the others. Manuscript profile

Pistachio is one of the most important horticultural crops in Iran. There is a unique role for amino acids in the plant response to stressful conditions, and special physiological role for Arginine (Arg) compared to other amino acids. The effects of this compound were investigated on vegetative and reproductive characters of bearing pistachio trees of ‘Ahmad-Aghaei’. The experiments were done as a factorial based on RCBD with four concentrations of Arg (0, 100, 200 and 300 µM) and three spraying stages (post harvest, flower buds swollen and flowering). Based on the results, Arg improved the vegetative and reproductive characters. Arg increased length and diameter of shoot, leaf area, the number of floweringbuds, the number of nuts in cluster, fresh weight of cluster, nut splitting (%) and ounce, and decreased flower buds abscission percent and blankness. Arg also significantly increased photosynthetic pigments (chlorophyll a and b and total chlorophyll) in bearing pistachio trees. The best concentration of Arg was 200 µM applied of the flowering stage, but the strongest effect on the number of nut in cluster, fresh weight of cluster and blankness were observed when spraying at the flower bud swollen stage. Manuscript profile

A greenhouse experiment was conducted to evaluate the freezing damage in some pistachio rootstocks by ion leakage and pH changes of leaked solution. A factorial experiment was carried out in randomized block designs (RBD) with three factors: Temperature (A) including 4 ̊C, 0 ̊C, -2 ̊C, -4 ̊C, -6 ̊C, Time (B) including 3, 12, 24h , and Rootstock (C) including P. vera cv 'Badami Zarand' (V13) and 'Sarakhs' (S5), P. mutica (M1)and P. atlantica (A7). For this, one-year-old seedlings were kept at these five temperatures in incubator for 2 hours. Then in the first 24 hours in three hour intervals and during four days, EC and pH in leaked solution were measured daily. After four days the seedling samples were autoclaved at temperatures 105°C for 4 minutes to destroy all cell membrane. EC and pH of remaining solution were measured again and the percentage of ionic leakage was calculated. The results showed that the best time to evaluate the pH and ionic leakage was 24 hours after incubation of samples. Based on the results, ionic leakage dramatically increased with decreasing temperatures from 0°C to -6°C, while pH of leaked solution had no significant difference in 0°C and 4°C temperature treatments. When temperature reduced from 0°C to -6°C, like ionic leakage, pH greatly reduced. So the pH of the leaked solution could be an appropriate tool to study the freezing damage of pistachio rootstocks. Based on the results of pH and ionic leakage, P. mutica and P. atlantica were the most frost tolerant and sensitive rootstocks of this experiment, respectively. Manuscript profile