Explain polyploid breeding.

Explanation

The polyploids are the plants, that possess more than two sets of chromosomes. Diploids (2n) number of chromosomes are present in majority of flowering plants. Polyploids often exhibit increased hybrid vigour by increasing heterzygosity Polyploidy increase the tolerance to both biotic and abiotic stresses. It offers a buffering effect of deleterious mutations. The production of seedless varieties is possible due to meiotic error, Polyploidy often results in reduced fertility and is considered to be major force in the evolution of both wild and cultivated plants.
Autopolyploidy and Allopolyploids are the two types of polyploids.
Autopolyploidy : The doubling of chromosome by itself in the same plant is called autopolyploidy.
Eg : Triploid condition in sugar beets, apple and per, In tomato it leads to seedless variety. Polyploidy can be induced by a chemical called colchicine.
Allopolyploids : The multiplication of chromosome sets that are initially derived from two different species, is called allopolyploidy.
Eg : Triticale (Triticum durum X secale cereale), Raphanobrassica (Brassica oleraceae X Raphanus satious).