Backcrossing
More than one American chestnut line also is needed, also
to avoid inbreeding, when B3s are intercrossed with each other.
¥C x A13
¥ø
¥F14
x A14
¥ø
¥B14
x A15
¥ø
¥B24
x A16
¥ø
¥B34
¥C x A9
¥ø
¥F13
x A10
¥ø
¥B13
x A11
¥ø
¥B23
x A12
¥ø
¥B33 x
¥C x A5
¥ø
¥F12
x A6
¥ø
¥B12
x A7
¥ø
¥B22
x A8
¥ø
¥B32
¥C x A1
¥ø
¥F11
x A2
¥ø
¥B11
x A3
¥ø
¥B21
x A4
¥ø
¥B31 x