Question

A classical example of allopolyploidy is?

• A. Brassica
• B. Raphano-brassica
• C. Raphanus
• D. All the above

Answer 1

The correct option is B Raphano-brassica

The number of sets of chromosomes in an organism is known as the ploidy number. Having two sets of chromosomes means that you are diploid or 2n. There are other animals and several species of plants that are polyploidy meaning that they have more than two sets of chromosomes.

There are times when organisms may contain two or more sets of chromosomes that are from different species. When this occurs, we refer to this as allopolyploidy.

Raphano-brassica is classical example of allopolyploids. This was pro­duced by a Russian Scientist Karpachenko. He crossed Raphanus lativus and Brassica oleracea and obtained F1 hybrid which was completely sterile. The sterility was due to complete non homology between the genomes of Raphanus and Brassica. But some plants of Raphanobrassica were fertile obviously due to the doubling of the chromosomes.

So, the correct answer is 'Raphano-brassica'.