Question

In a cross between 4n female plant and a 2n male plant of mulberry the endosperm would be

Answer 1

When we cross a diploid female plant (2n) with a tetraploid male (4n), the endosperm formed will be tetraploid. This can be explained as follows:
Parents: 2n (Diploid female)   ×​       4n (Tetraploid male)

Gametes:   n (Female gamete)   ×       2n (Male gamete)

Zygote: 3n

Endosperm is formed by the process of triple fusion, wherein one male gamete fuses with the two polar nuclei. In this case, the two polar nuclei are haploid but the male gamete is diploid (2n). Hence, the endosperm would be tetraploid (n + n + 2n = 4n).
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