Course Content
Learn Introductory plant breeding with Braimy- B.Sc agriculture
About Lesson

A) Based on origin

  1. Spontaneous mutations :
  • Mutations occur in natural populations at a low rate (10-6) but different genes may show different mutation rates.
  • For example : in maize R-locus mutates at the frequency of 4.92 x 10-4 i.e. (1 in 20000 population), when as Su locus at 2.4 x 10-6 ( 1 in 25 lakhs).
  • The Wx locus considered to be highly stable.
  • The difference in mutation rate may be due to a) Genetic back ground i.e. presence of mutator genes b) Genes themselves c) Environment

Genetics: Spontaneous mutations lead to mental retardation | Spectrum |  Autism Research News

2.Induced mutation :

  • Mutations may be artificially induced by treatment with certain physical or chemical agents.
  • Available evidence indicates that induced mutation rarely produces new alleles they produce alleles which are already known to occur spontaneously.
  • Induced mutations are comparable to spontaneous mutations in their effects and in the variability they produce.
  • Induced mutation occurs at a relatively higher frequency so that it is practical to work with them.

Spontaneous and Induced Mutation - BIOLOGY EASE

B) Based on magnitude of phenotypic effects

  1. Macro mutations:
  • Oligogenic Mutation – Large phenotypic effect and recognizable on individual plant basis and can be seen easily in M2 generations.
  • Ancon breed in sheep, pod maize to cob maize.

Sentient Developments: Ripley's macromutations

  1. Micro mutations :
  • Polygenic mutations – Small phenotypic effect which cannot be recognized on individual plant basis but can be recognize only in a group of plants. Selection should be done in M3 or later generations.

Rag Tag Bobtail Triplet Frog Found Editorial Stock Photo - Stock Image |  Shutterstock Editorial

Join the conversation
Scroll to Top