Optimizing Storage and In vitro Germination of Date Palm (Phoenix dactylifera) Pollen

Iran is one of the main date (Phoenix dactylifera) producing countries in the world. however, little information is available on the pollen viability and favorable storage conditions of Iranian male date cultivars. This study was conducted to estimate the best in vitro pollen germination of three male date palm cultivars, `Ghanami’, `Samsmavi’ and `Gheibani’ using various doses of boric acid (۰, ۵۰, ۱۰۰ and ۲۰۰ mg L-۱), calcium nitrate (۰, ۲۰۰ and ۳۰۰ mg L-۱) and sucrose (۱۵% and ۲۵% (w/v)) in a Modified Brebaker and Kwack (MBK) medium. The results showed that the best germination was achieved with ۵۰ mg L-۱ boric acid, ۲۰۰ mg L-۱ calcium nitrate and ۱۵% (w/v) sucrose. Once the optimal in vitro germination medium had been established, pollen viability (% germination) of these three cultivars stored for up to ۲۰۰ days at room temperature (dark and light), in a refrigerator (۴˚C), freezer (-۲۰˚C) and in liquid nitrogen (-۱۹۶˚C) was compared. For all the tested cultivars, germination declined as storage temperature increased and, by ۲۰۰ days, the highest survival rate was obtained with cryostored pollen. Long-term storage of date pollen using an ultra-low temperature (-۱۹۶˚C) can be used without any deteriorating effect on pollen viability, while room temperature storage significantly reduced pollen germination.