What causes chaffy empty grains in paddy panicles?

Chaffy, empty grains come from spikelet sterility, where flowers do not set grain, caused by temperature stress at flowering, water stress, nutrient imbalance, pest and disease damage, or poor pollination. Very high temperature above the mid 30s Celsius or cold nights during flowering both cause empty grains, so adjust sowing time so flowering misses extreme heat or cold. Keep adequate water and a thin layer at flowering, ensure balanced potash and avoid heavy late nitrogen, and control panicle stage pests like stem borer and bugs and diseases like neck blast and false smut. Boron or zinc deficiency can also reduce grain set. Match variety and sowing date to your local climate window to avoid heat or cold at flowering.