The viability of Polyploid Lilium pollen can vary considerably. An easy way to determine its viability prior to using it, is to germinate some of the pollen In Vitro. This will allow you to increase your pollination success rate with your crosses of your polyploid liliums.
The number of pollen grains needed for pollination is equivalent to the number of ovules. When the pollen is placed on the stigma under the right conditions the pollen grain germinates and produces a pollen tube. The pollen tube acts as a conduit to transport sperm cells from the pollen grain, which has landed on the stigma, to the ovules at the base of the pistil. The pollen tube germinates from the pollen grain and grows the entire length through the stigma, style and ovules to reach the eggs.
We can exploit the fact that the pollen produces pollen tubes to determine its viability by using the following procedure.
In Vitro Pollen Germination 
right conditions the pollen grain germinates and produces a pollen tube. The pollen tube acts as a conduit to transport sperm cells from the pollen grain, which has landed on the stigma, to the ovules at the base of the pistil. The pollen tube germinates from the pollen grain and grows the entire length through the stigma, style and ovules to reach the eggs.
We can exploit the fact that the pollen produces pollen tubes to determine its viability by using the following procedure.