Effect of gamma radiation on percent survival, lethality percentage of axillary buds of apple cv Ambri and determination of Lethal Dose (LD50)

Abstract

This study aimed to determine the optimum lethal dosage (LD50) of gamma rays in apple and to study the effect of gamma irradiation on percent survival and lethality percentage of axillary buds of apple cv Ambri. Development of new cultivars of apple, when attempted through traditional methods, is a tedious and time consuming exercise which takes dozens of years due to various reasons including the perennial nature, heterozygosity, prolonged juvenile phase and sexual incompatibilities. For this reason, the breeders have been forced to attempt mutation techniques to induce genetic variation and procure sudden heritable changes in the genetic material of the fruit at the cellular level. Gamma radiation is one of the physical mutagens that has been widely used for mutation breeding to improve the genetic traits of several crops. A total of 180 scions were exposed to 0,2.5, 5,7.5,10,20,30 Gray (Gy) of gamma radiation, using a Cobalt-60 source at dose rate of 0.0618 Gy/h. The percentage of plant survival decreased with the increase in dose of gamma rays. The lowest survival rate was shown by 30 Gy-treated samples. The LD50 value was calculated to be 35 Gy which will be preferred for further studies.