Effect of flowering stage and storage conditions on pollen quality of six male date palm genotypes.

Availability of efficient male genotypes is critical for successful artificial pollination and regular bearing of female date palms. The effect of flowering stage and storage conditions on pollen quality of six male date palm genotypes encoded 'ABD1', 'P4', 'P3', 'P8', 'P7' and 'P13'were evaluated. Pollen collected from spathes developed at the middle of flowering stage exhibited the best viability (90%) and germinability (85%) compared to other stages. Pollen viability was greater than 90%, except for 'P8' that exhibited 80%, while, germinability greatly varied among the genotypes. Pollen quality decreased during 4 months of storage upon genotype and temperature, with a minimum reduction at -30 °C followed by 4 °C. Heat shock exposure (33 ± 2 °C) following storage revealed that pollen stored at -30 °C or 4 °C should be used for pollination on the same day of take out to avoid dramatic quality loss. The 'ABD1', an early flowering genotype, proved highest pollen quality both at fresh stage and after storage. While, the 'P3', a late flowering genotype, retained its pollen quality during storage. However, the 'P13' genotype exhibited excellent pollen quality when fresh, but greatly loses germinability during storage.