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. تفاصيل المقالة

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. تفاصيل المقالة