If male plant is hexaploidy and female plant is tetraploid, the endosperm will be :
If male plant is hexaploid. then the gamete formed will be 3n. If the female plant is tetraploid then the gametes formed will be 2n. The endosperm is formed by the fusion of the two polar nuclei with the male gamete.
The endosperm will have 2n+2n+ 3n= 7n