Prasad et al., (2006):Spikelet fertility was estimated as the ratio of number of filled grains to total number of reproductive sites (florets) and expressed as percentage. Each floret was pressed between the forefinger and thumb to determine if the grain was filled or not. Number of filled grains included both completely and partially filled grains。
All florets were divided into three parts:filled, half(partially)filled and unfilled
The grains per panicle are usually divided into two categories, one is full grain and the other is empty grain. Among them, full grain is the real measure of the number of grains per panicle, and the ratio of full grain to the total number of grains per panicle is called the seed setting rate. Please Follow this Research Paper