My paddy panicles are full of empty chaffy grains, why no filling?

Empty, light, chaffy grains where the panicle did not fill can have several causes, so this one needs careful checking rather than a single quick answer. The most common reasons are cold or very hot spells at the flowering and pollination stage, water stress or sudden drying at grain filling, hopper or bug feeding that drains the developing grain, neck blast or false smut interfering with filling, and sometimes a potassium or boron shortage or excess nitrogen that gives lush plants but poor filling. To narrow it down, think back to the weather around flowering, check whether the empty heads are in particular patches or all over, and look for any borer holes, hopper colonies or neck discolouration; please send photos of the affected panicles and a note of the flowering dates to your KVK or agri officer so they can pin the cause. Getting the soil tested helps rule out a nutrient cause. There is no spray that fills already empty grain, so the plan is to identify the true reason and fix it next season, for example adjusting sowing time so flowering avoids extreme temperatures, keeping steady moisture at grain filling, controlling sucking pests in time, and balancing the nutrition. Confirm the diagnosis and the corrective steps with your local KVK before next sowing.