This study evaluated the effect of artificial pollination on pistachio trees in an orchard at a low ratio of male to female trees in Qazvin province, Iran, over the years 2012-2013. Experimental factors included three female cultivars (Akbari, Owhadi, Kalebozi) and three types of pollinizer (Control, GA, and GB) with three replications. In each female tree, two branches were selected in the northern and southern directions and bagged before flowering. When stigma was ready to receive pollen, artificial pollination was carried out using the male genotypes GA and GB. The traits of some fertilized flowers per cluster, initial and secondary abscission of flowers and fruits, number of fruits per cluster, nut dry weight per cluster, nut dimension, blankness percentage, and non-split nuts percentage were investigated. The results indicated that artificial pollination in three stages after flowering not only increased the quantitative traits such as number of flowers and fruits per cluster but also reduced the percentage of non-split fruits and blank fruits in all cultivars. The highest and lowest numbers of fertilized flowers were obtained by pollination with GA (91.67) and open pollination (73.89), respectively. Besides, the lowest and highest percentages of initial and secondary abscission of flowers belonged to pollination by GA (13.11-21.44 %) and open pollination (18.33-42.11%), respectively. In addition, the highest initial (54.44) and final (27.66) fruit sets per cluster, the lowest blank nuts (18.01%), and non-split nuts (17.62%) were achieved using pollination with GA. Therefore, it can be concluded that GA is the best male tree for pollination. Akbari cultivar showed the highest nut dry weight per cluster (34.81 g) and the lowest (14.53%) percentage of blank nuts. Manuscript profile

This research was conducted to determine the effect of salicylic acid on the drought tolerance of three pistachio (Pistacia vera L.) rootstocks. The treatments were included three irrigation levels (Control: 100 % ETc, medium stress: 65% ETc, and severe stress: 30% ETc), three pistachio rootstocks, and three salicylic acid concentrations (0, 1, and 3 mM). The salicylic acid solution was once applied as a foliar spray, starting water stress, and irrigation treatments continued for 75 days. Results showed that P. vera ‘Badami Zarand’ was less affected by water stress treatments than the other seedling rootstocks. Among the rootstocks studied, the highest photosynthesis rate (6.55 µmol CO2 m-2 s-1) was obtained in P. vera ‘Badami Zarand’ under severe water stress (30 % ETc) and 1 mM salicylic acid application. The lowest photosynthesis rate (2.75 µmol CO2 m-2 s-1) was observed in P. vera ‘Sarakhs’ under severe water stress (30 % ETc) and 3 mM salicylic acid treatment. In addition, the highest relative water content (66.16%) and the lowest ion leakage (33.29%) were obtained in ‘Badami Zarand.’ The 1 mM salicylic acid application effectively reduced the negative effects of water stress. According to the results, P. vera ‘Badami Zarand’ showed a better response to salicylic acid under stress conditions, and the highest photosynthesis, relative leaf water content, dry weight of organs (leaves, shoots, roots), and the lowest ion leakage under drought stress belonged to this rootstock. Manuscript profile

Pistachio is one of the economic nut fruits in Iran. Water limitation is the most restrictive factor for its production. To overcome the water scarcity crisis, introducing drought-tolerant rootstocks is among the crucial breeding strategies. To investigate the drought tolerance of five Qazvin native pistachio genotypes, an experiment was carried out as a factorial experiment in a completely randomized design with four replications in the greenhouse conditions. The factors were pistachio genotypes (Madari, KalKhandan, Kalehbozi, Sefid, and Ghermez) and irrigation regime (normal conditions and drought stress). The highest relative water content under drought irrigation conditions belonged to the Sefid (59.99%), and Ghermez (59.09%) genotypes. The lowest value (54.68%) belonged to the Madari genotype. The highest electrolyte leakage under drought irrigation conditions belonged to the Madari genotype (55.75%). The lowest electrolyte leakage (42.44%) belonged to the Sefid genotype. Under drought stress, the highest amount of chlorophyll a (2.12 mg g-1 fresh weight), total chlorophyll (3.051 mg g-1 fresh weight), and carotenoid (2.38 mg g-1 fresh weight) was observed in Ghermez genotype. In contrast, the highest amount of chlorophyll b (1.34 mg g-1 fresh weight) was observed in the Sefid genotype. The lowest amounts of chlorophyll and carotenoid in the drought stress belonged to the Madari genotype. According to the results, the Ghermez and Sefid genotypes with lower electrolyte leakage and higher relative water content, chlorophyll, carotenoid, and biomass under water stress, were the more drought-tolerant genotypes. Madari and KalKhandan genotypes with higher electrolyte leakage and lower relative leaf water content, chlorophyll, and biomass were the most drought-sensitive genotypes. Manuscript profile

Infection of pistachio nuts with Aspergillus flavus and aflatoxin is one of the serious and important threats in the process of production, export, and consumption of pistachios in the world. Aflatoxins are secondary metabolites that are mainly produced by A. flavus and A. parasiticus. Aflatoxins are generally produced before harvesting and under horticultural conditions. Early-splitting pistachios are one of the most significant sources of contamination to aflatoxigenic fungi in the orchard. In the present study, the population density of Aspergillus section Flavi and aflatoxin content were investigated in early-splitting, irregular cracking, and intact pistachios of the Shahpasand cultivar. Sampling was done from the pistachio orchard of Damghan Pistachio Research Station in the first half of August, and pistachio kernel contamination and population density of the fungus were investigated. Pistachio samples were cultured on an AFPA medium using a serial dilution method (completely randomized design with three repetitions). Aspergillus section Flavi colonies were identified and counted and after three days at 28°C and dark. Aflatoxin contents of pistachio kernels were quantified by high-performance liquid chromatography (HPLC) method. The results were statistically analyzed by SPSS statistical software and the means were compared using Duncan's multiple range test. The results showed that the highest and the lowest contamination rates for Aspergillus section Flavi and aflatoxin have belonged to early-splitting and intact nuts, respectively (P≤0.05). The contamination rate in early splitting pistachios is much higher than in irregular cracking and intact kernel pistachios. Manuscript profile