once a genetic cross becomes established it tends to stay the same .

This ratio approximates the result of a recessive lethal gene for albino at only 1 locus a 3:1 ratio.

In that case I'll call the gene G for green and A for albino

Of the p;ants

1/4 = GG green
2/4 = GA green
1/4 = AA white (died)

Of survivors GG:GA = 1:2

Random crossing of these gives

4/9 = GG green
4/9 = GA green
1/9 = AA white (died)

Of survivors GG:GA = 1:1

Random crossing of these gives

9/16 = GG green
6/16 = GA green
1/16 = AA white (died)

Of survivors GG:GA = 3:2

Etc.

George