The materials (dry palmarosa seeds with 12% moisture content of four cultivars 'Tripta', 'Trishna', 'PRC' and 'MP') and methods of gamma rays (15 Kr, 60CO source with dose rate 0.38 Mrads\h) and chemicals ethyl methane sulfonate (EMS - 0.4%) and ethyleneimine (EI-0.04%) induced mutagenesis. The seed of the four varieties had already been selfed for 4-5 flowering seasons before mutagenesis to maintain genetic homogeneity (or purity) and thereafter all the selected M1 generation suspected mutant plants were individually selfed by bagging to give rise to controlled M2 plant to progeny segregants for further selection. Oil content was estimated on freshly harvested herbage (stems, leaves and inflorescence) using a Clevenger-type apparatus.

The oil content was increased in all the 20 mutants as compared to their respective contols. Most M2 generation mutants were found to exhibit a straight relationship between high herbage (stem, leaves and inflorescence) yield, oil content (%) and oil quality in terms of major and trace constituents of the oil. Six mutants specifically were endowed with the desirable rosy note which remained predominant in the samples of Trishna-gamma-5, MP-gamma-13, Tripta-gamma-8, Tripta-Ethyl methane sulfonate (EMS)-19, Tripta-EMS-21 and PRC-Ethyleneimine (EI)-44. The fresh herbage and oil yield and odor criteria, i.e., rosy note were satisified by the three best mutants, viz., Trishna-gamma-5, MP-gamma-13 and Tripta-gamma-19. The results have been interpreted in the sense that induction of mutations brings about gene level changes from dominance to recessive and vice versa in morpho-economic traits having quantitative trait loci (QTL) under polygenic genetic control.