Study of Some Compound Oil Treatment Effects on Germination and Level of Pollen Grain Production in Dormant Male Pistachio Trees

A lack of adequate annual chilling in temperate zone fruit growing trees, especially pistachio is a main problem observed in many areas with partly warm winters. Usually this phenomenon results in disorders in vegetative and reproductive structures, decrease in production of pollen, falling of flower buds and decrease in or loss of fruit set. Presently the use of some substitute chemical compounds which somehow compensate for the lack of chilling requirement is confirmed by some scientific reports. This research was done in Iran’s Pistachio Research Institute during early Feb 2006 and 2007 on four male pistachio genotypes [tow early (P1, P6) and two late flowering (P7, P10)] to determine the role of oil compounds on breaking of dormancy, germination and amount of pollen grains. Selected genotypes had been introduced as the most suitable pollinators for Iranian commercial pistachio cultivars in some previous studies. The oil compounds used as treatments in the study were Volck oil (mineral oil) (4%), soybean oil (5%) and fatty acids (4%). This experiment was designed in split plot, based upon random complete block the main plots of which were genotypes, and the secondary plots oil compound treatments. The factors recorded included: date of bud break, quantity (mg) and quality (percentage of germination) of pollen grains. The results revealed that trees treated with oil compounds went into anthesis 2-4 days earlier than the untreated ones. Pollen grain production in treated tree branches, as compared with control, did not show any significant differences. In this experiment, it was shown that Volck oil (4%), and soybean oil (5%) had more positive effects on germination of pollen, in In vitro conditions.