Induction of Somatic Mutations in Some Horticultural Crops by Chronic Gamma Irradiation

By treating growing potted plants to semi-acute exposures of gamma rays from Co⁶⁰ source, a total of seven propagable type of somatic mutants have been isolated in fruit trees and ornamentals. Radiation induced tetraploid, one each in Lucknow-49 guava and Anab-e-Shahi grape have been isolated and are expected to be useful for the exploitation of polyploidy in fruit variety improvement. In Alipore Beauty Hibiscus, two somatic mutants—one with deep red flower colour and the other with deep red flower colour coupled with semi-double form have been spotted out and perpetuated vegetatively as stable types. Similarly, in Cruenthus Hibiscus, a mutation with change of flower form from double to single type has been picked up and established asexually as a new type. In Iresine, two foliage colour variants have been isolated and multiplied vegetatively as stable colour forms. The change of colour in different histogenic cell layers has been established by a comparative anatomical study. AH these above mutants are useful and expected to find a place in Horticultural improvement as newer types industry of the country.