PRIMARY EFFECTS OF GAMMA RADIATION (Cz137) ON THE MORPHOLOGY OF LEAVES AT SOME SWEET CHERRY VARIETIES

Abstract

The study has been conducted based on the presence of atypical leaf morphology, in relation to leaf shape, size, color, leaf nervation, leaf stem length and leaf stem thickness, as a primary effect product in the first MV1 generation after the gamma radiation with Cz137 on Bigareau Burlat, Pobeda Krimska and Kozerska cherry varieties. The selected leaf radiomorphosys were used as conservative and accurate signs for early detection of somatic mutations caused by radiation. Graft branches were exposed with dosages of 25Gy, 35Gy and 45Gy at the Institute of Radiobiology and Radiopreservation in Sofia. The grafting was performed with dormant buds onto Prunus mahaleb rootstock. The dosage augmentation caused average reduction of leaf dimensions and leaf stem lengths in all of the tested varieties. Also, with the augmentation of the radiation dosage, the
percentage of chlorophyll deficiency leaves increased from 1,1% at 25Gy to 7,4% at 45Gy. An average of 47,5% of the analyzed leaves have an atypical shape, without significant differences between the varieties, and 14,5% of the leaves have an atypical leaf nervation. The highest percentage of leaves with atypical shape and leaf nervation are represented in plants treated with a dose of 45Gy.