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Life Science Research and Sustainable Development ISBN: 978-98-84663-33-9

Vitis vinifera L. grape 1
Weigela sp. weigela 3
Zea mays L. maize 68
Ziziphus mauritiana Lam. indian jujube 2

Among the total 2,252 mutant varieties, there were 1,585 verities developed Mdirectly’ after
mutagenic treatment and selection in the subsequent generations. However, in many cases
mutants or already released mutant varieties have been used as sources of desired characters in
cross breeding programmes; in this way, 667 new varieties were developed. Of 1,585 directly
developed mutant varieties, a great majority (1,411) were obtained with the use of radiation as
the mutagen (Table 4).

Table 4: Number of officially released mutant cultivars developed with different types of
radiation

Type of mutagen Number of released mutant Percent of total
cultivars
Radiation* 1411 100.00
gamma rays* 910 64.49
x-rays* 311 22.04
gamma chronic 61 4.32
fast neutrons** 48 3.40
thermal neutrons 22 1.56
other 24 1.70
*including various treatments; **including “neutrons”
Source: Plant Breeding and Genetics Section Joint FAO/IAEA Division/ Mutant Variety
Database, 2020.

Applications of mutation breeding
Mutation breeding has been used for improving both oligogenic as well as polygenic characters.
It has been employed to improve morphological and physiological characters, disease resistance
and quantitative characters including yielding ability. The various applications of mutation
breeding may be briefly summarized as under.
In mutation breeding techniques desirable mutant alleles are induced, those do not present in the
germplasm or which may be present, but may not be available to the breeder due to political or
geographical reasons. Mutation breeding relieves the complete dependence of breeders on the
natural germplasm. But it should be remembered that mutation breeding cannot minimize the
necessity of germplasm collections; it only serves as a useful supplement to the available
germplasm.
Mutation breeding is useful in improving specific characteristics of a well-adapted high yielding
variety. This is particularly so in the case clonal crops due to their highly heterozygous nature; in
such acase, mutagenesis is the only method available to improve the specific characteristics of
cloneswithout changing their genetic makeup.
Mutagenesis in self-pollinated species, is useful in improving the specific characteristics of
otherwise adapted and superior varieties. However, in such species mutagenesis may not be

https://jesjalna.org/Zoology-Publications/index.html 12 Department of Zoology, J. E. S. College, Jalna