Inter-specific cross of Arachis hypogaea (2n= 4x= 40) and Arachis correntina x Arachis helodes (2n= 2x= 20) yielded the unstable triploid and sterile derivatives. The ploidy level of this triploid (3x) was then doubled with colchicine to get an unstable hexaploid derivative. The paper presents the cyto-morphological features of the produced unstable derivatives so as to frame a suitable breeding strategy to evolve the stable culture tolerant to major foliar diseases. Phenotypic attributes like leaf colour, length and width of calyx tube, poor pollen fertility and abortive ovarian system were found to be dominant in the triploid. Hexaploid progeny possessed leaves with larger veins, semi spreading habit, slow growth, shriveled anthers and improved pollen fertility as compared to triploid. The normal meiotic behaviour was witnessed among diploid and tetraploid parents while abnormal meiotic system as evidenced from the formation of trivalents and quadrivalents was noticed among triploid and hexaploid derivatives. Abnormal sporads also recorded among triploid and hexaploid leading to formation of sterile pollen grain.