Am I allowed to bring a 10-kilo biryani rice bag in my check-in luggage? Flying from Muscat to the Philippines.
Most likely the airline and the departure security do not mind.
But when you arrive in the Philippines you will likely be stopped bringing it in any further. Many countries have a ban on bringing in certain food stuffs and even more on agricultural seeds and other items.
If/when you bring your rice with you, select to see a customs or imports security officer (or whatever they are called there) and check with them whether you are allowed to bring the bag in. Rather likely you will have to leave it behind to be destroyed, but you will not be charged with illegal imports. On the other hand, if you bring it in without declaring you can be charged with illegal imports, endangering the nature and agricultural produce of your country.
Not worth it.