S. saha* and a. paul
Department of Genetics & Plant
Breeding and Crop Physiology, Institute of Agriculture (Palli Siksha Bhavana),
Sriniketan-731 236, India
Author Email :
Aim: Effect of gamma
irradiation on genomic disorder in sesame are scanty. The present study was
undertaken to evaluate the mutagenic effects of gamma rays on different
parameters in two popular cultivars of sesame, Roma and Tilottama.
Methodology: Seeds of these
two cultivars were irradiated with five doses of gamma rays: (250, 300, 350,
400, and 450 Gy) at BARC, Trombay and were sown (along with the un-irradiated
control) during March 2015 in a split plot design with 3 replications keeping
row to row and plant to plant distance at 30 cm and 10 cm, respectively to
determine mutagen sensitivity with regard to pollen fertility (%),
germination (%) and seedling height (cm), root-shoot length (cm), plant
survival (%) at maturity in M1 generation. To study mutability, four to five
capsules from each M1 plants in all the treatments were collected
separately to give rise the M2 generation. Individual plant progeny rows were
sown in M2 during March 2016. ID50 was determined by
probit analysis for germination, shoot-root length and plant survival. Since
the dose requirement for pollen fertility is very high, ID30 was
calculated instead of ID50 value.
Results: It was observed
that with increasing doses of gamma rays, the response of all characters
decreased significantly and followed a linear relationship in both varieties.
The root system was more profound to gamma rays than the shoot. Chlorophyll
mutations showed independent response to different doses of gamma rays as
they occurred in random. The mutability of genotype Roma induced with
different doses of gamma rays was higher than that of Tilottama.
Interpretation: Due to saturation
in the mutational actions, response of characters decreased with increase in
gamma ray doses but magnitudes of effect differed between genotypes. The
cultivar Tilottama was found to be more sensitive than Roma.
Key words: Gamma rays, Inhibitory dose, Mutability, Mutagen