Booting – this stage is loosely defined as that period characterized by a swelling of the flag leaf sheath which is caused by an increase in the size of the panicle as it grows up the leaf sheath. Full or late boot occurs when the flag leaf has completely extended. Booting is the stage in which meiosis occurs. Environmental stress during this stage may reduce rice grain yield. Late boot occurs about 6 days prior to heading. This date can be predicted by the DD50