Optimization of gamma-ray irradiation dose for induced mutagenesis in field corn (Zea mays L.)

Abstract

The present investigation was carried out to optimize the dose of gamma rays for practical mutation breeding application in field corn. An elite maize inbred line (PML-93) was irradiated with 10 different doses of gamma rays and seedling traits and growth parameters were evaluated by the paper towel and pot method. The observation of seed and seedling growth parameters such as germination percent, mean root length (MRL), mean shoot length (MSL), mean root dry weight (MRDW), mean shoot dry weight (MSDW), vigour index I (V-I), vigour index II (V-II) were recorded. The study revealed significant variations in all the traits under investigation in both the paper towel and the pot method. Out of 10 doses, the dose of 200 Gy was found optimum, it showed a 50 percent growth reduction (GR) in terms of most of the above growth parameters. Further, karyotype analysis showed that the chromosome breakages at one or two places as compared to the control. These aberrations may lead to heritable variation. Hence mutation breeding approach can be undertaken to create variability within this inbred line. The generated variability can be the best source to explore potential mutant line/s for the future breeding program.