What will be the ploidy of endosperm, if the male and female parents are tetraploid and hexaploid, respectively?
Male is tetraploid, hence , the gametes formed will be diploid.
Female is hexaploid, hence, the gametes formed will be triploid.
The endosperm is formed by the fusion of male gamete with the secondary nucleus.
Therefore, the endosperm will be 6X+2X=8X