This trait of a male sterile line is monitored at growth stages 8 and 9. Two primary panicles of at least 50 plants of a male sterile line are bagged with glassine bags at growth stage 5-6 before their anthesis begins. Filled and unfilled spikelets of the bagged panicles are counted. Pollen grains are squeezed out from some anthers in Acetocarmine stain and observations are made on their staining behavior and number of nuclei visible in most of the pollen grains. This trait is monitored at growth stages 8-9 of a male sterile line grown in the field where pollen supply at its flowering time is abundant.
Seed set on the out-pollinated primary panicles is observed.
This trait is monitored at growth stage 6 by observing the extent of coverage of panicles by the flagleaf sheat. This trait is monitored at growth stage 6-7 by counting number of florets which have completed anthesis on a given day and the number of florets showing exserted stigma on one or both sides of the florets and expressed as percent stigma exsertion. However, in this case, emphasis is one extent of fertile pollen percentage. Spikelet fertility is monitored by counting the number of filled grains and total spikelets per panicle and converted into percentage.