Somaclonal variation in pomegranate (Punica granatum L.): ISSR and cytological evidences

Abstract

New advancements in tissue culture techniques have resulted in vitro propagation of several regenerations of horticultural crops. The somaclonal variation which occurs during plant tissue culture is a potential source for inducing new genetic variability in such crops. Several approaches have been utilized to ascertain the occurrence of somaclonal variation. The pomegranate plant can adapt to various environmental conditions and grow well in different kinds of soil and climate. Pomegranate Zagheh cultivar is mainly cultivated in the state of Esfehan, Kashan city in Iran. The present study was performed to investigate the potential occurrence of somaclonal variation in tissue culture regenerated plants of the cultivar Zagheh and provide morphological, cytological and molecular evidences for its occurrence. Nodal segments were chosen for the in vitro propagation of pomegranate. Explants were cultured on MS basal medium. We carried out both molecular (ISSR) and karyological studies in propagation collected. In the present study, we observed variation in both morphological (length of shoot, branch, internode, leaf and root and number of branch and root) and genetic features of the tissue culture regenerated plants. The regenerated plants of the third sub-culture differed from mother plants in the ISSR marker. We observed frequent occurrence of cells with different chromosome numbers, ranging from normal diploid 2n = 2x = 16 to tetraploid 2n = 32 chromosome number.