Question

A female plant with ploidy 6n is artificially hybridized with a male plant with ploidy 4n. Upon successful reproduction, in seeds produced, the ploidy of endosperm and embryo will be ___________ and ____________.
(a)3n and 2n
(b)16n and 10n
(c)8n and 5n
(d)7n and 5n

Answer 1

Hint: Ploidy is the number in a cell of full sets of chromosomes and hence the number of potential autosomal and pseudoautosomal gene alleles. The number of sets of chromosomes present can classify somatic cells, tissues, and individual organisms: monoploid (1 set), diploid (2 sets), triploid (3 sets), tetraploid (4 sets), pentaploid (5 sets), hexaploid (6 sets), heptaploid, etc. To identify cells with three or more chromosome sets, the common term polyploid is sometimes used.

Complete answer:
It is provided that 6n ploidy is present in the female plant. The female gamete would also have 3n chromosome numbers. The male plant has 4n ploidy, similarly. The number of chromosomes in the male gamete, therefore, will be 2n. After fertilisation, there will be 3n + 2n = 5n ploidy in the embryo and 3n + 2n + 2n + 2n = 7n ploidy in the endosperm.
Interspecies dependent on endosperm or interploid hybridization barriers relies on the hybridization path, causing non-reciprocal seed defects. This shows that parental genomes are not identical, suggesting unique genes of parent-of-origin that produce this form of barrier to hybridization.

Additional Information: The pairing or crossing of two dissimilar genotype plants or lines is known as hybridization. The crossing is carried out in plants by placing pollen grains from one genotype, i.e., male parent, on the stigma of flowers from another genotype, i.e., female parent.
So, the correct answer is ‘7n and 5n ‘.

Note: Hybridization in plants is important, particularly in agriculture, where a hybrid crop that is both hardy and disease-resistant is used to grow. Examples of a hybrid are ligers and mules in livestock. In molecular biology, the mechanism of forming a double-stranded nucleic acid from two complementary DNA(or RNA) strands is hybridization.