Mutation Induction and Creation of Variation in Strawberry, Kurdistan Cultivar, by Gamma Irradiation and Determination of Suitable Irradiation Dosage

Genetic diversity in strawberry is low due to its asexual propagation. One method of increasing genetic diversity, as an important tool in plant breeding, is the use of gamma rays to induce mutation. In order to determine the appropriate dosage of gamma irradiation for genetic diversity creation by mutation in strawberry, Kurdistan cultivar, and to study the influence of various doses of gamma ray (zero (control), 15, 30, 60 and 90 gray) on different traits of strawbery, this research was conducted in Faculty of Agriculture, Yasouj University, in 2012-2013. Results showed that irradiated plants had a lower rates in comparison to the control plants for most of the studied characteristics, except for number of leaves, fruit sugar and anthocyanin. Leaf area, fruit length, fruit diameter, fruit fresh and dried weight, and fruit volume, shape, and juice decreased with an increase in the gamma irradiation dosage. Moreover, multifoliate and dwarfism were increased in the irradiated plants. The appropriate dosage of gamma irradiation for mutation induction in strawberry, Kurdistan cultivar, for threshold 50% plants mortality (LD 50 ) treated by gamma ray, was approximately 65-70 gray. Therefore, gamma ray intensity in the recommended limit could be used for the highest genetic diversity creation with the lowest plant mortality in strawberry breeding programs such as in fruit quality improvement.