**4.3.2 Whittling the stem of scion into wedge end**

The robust soybean seedlings are selected as scions. The roots are first rinsed with tap water, and then dried out with the filter paper. After that, the stem of soybean seedling is shaved down to the wedged end from the top root hairs with the wallpaper blade, and the wedge length is generally 1.0-1.5 cm.
