Question

if a tertaploid female plant is crossed with a hexaplaoid male plant then what is the ploidy of endosperm? ​

Answer 1

depends on the plant. Being a rose-nut myself, I can give an example that contradicts the answer given by Harsha Chowdhury.

Roses in the Caninae-section undergo . Most species — if I recall correctly — are pentaploid (5n), and when they reproduce, the female parent gives 4n and the male parent gives 1n. There are a group of hybrids of called Alba Roses, which were primarily derived from crosses with Damasks and/or Gallicas, which are both 4n and produce 2n gametes. The results of these hybridizations will vary based on which was the female parent. Most Albas in cultivation seem to have originated from crosses with R. canina as the female parent, and a Damask or Gallica as the male parent. The result is a 6n Alba, with 4n from R. canina and 2n from the Damask or Gallica. These roses still carry out unbalanced meiosis, but now being 6n rather than 5n, they produce 4n as female parents and 2n as male parents. So if you use the pollen from a 6n Alba on a 4n rose, the offspring will be 4n (2n from each). If, instead, you use the Alba as the female parent with a 4n male parent, the result would be 6n.

There are several species in the Caninae-section besides R. canina, such as R. glauca and R. rubiginosa. This is probably why these species haven’t been used as much by breeders, since their unusual ploidies and unbalanced meiosis makes for some headaches. But in Germany has been successful using the 6n Alba as a male parent with modern 4n roses as female parents, which resulted in 4n offspring that could be bred further. Apparently, after a few generations, the unbalanced meiosis breaks down, and the hybrids partake more of their non-Caninae ancestry.

Answer 2

Answer:

$\huge\mathfrak{Answer\:♡}$

The 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).

$\mathcal{thnku :)}$