RADIO-SENSITIVITY IN RAGI (<i>ELEUSINE CORACANA</i>)

Abstract

Dry seeds of three varieties of ragi (Eleusine coracana) were subjected to gamma irradiation with acute dosage of 20 Kr and 30 Kr. The mutagenic effects of gamma rays in the M 1 generation and the mutation frequency with regard to chlorophyll and viable mutations in the M 2 generation were studied.The LD 50 appears to be around 30 Kr for ragi, although there are enormous varietal differences. Purna is the least and H 22 the most sensitive to gamma irradiation in the M 1 generation. There is a direct correlation between the radiation effect produced as measured by seedling growth, pollen fertility and seed fertility with the dosage used. Multivalent formation, lagging chromosomes and stickiness, etc. were observed in meiotic studies in the M 1 generation.The frequency of chlorophyll mutations was less in populations irradiated with 30 Kr than with 20 Kr. A wide spectrum and a high frequency of viable mutations were produced in Purna. The mutation frequency (viable + chlorophyll) increased with the dosage. The 200 isolated viable mutations included many agronomic types which are useful either directly or in conventional plant breeding.