Professionally speaking, at the jointing stage of rice, the fifth internode began to elongate from top to bottom, and the young panicle began to differentiate. Therefore, the early-maturing varieties with 3 or 4 elongated internodes are already in the stage of young panicle differentiation at jointing stage. For medium-mature varieties with five elongated internodes, this is the time when young panicles begin to differentiate at jointing stage. For late-maturing varieties with 6 or 7 elongated internodes, when the second or third internode is jointing, the young panicle just begins to differentiate.
This is the legendary booting stage of rice!