Gamma ray induced variation in cumin (Cuminum cyminum L.)

Cumin is an important spice crop of Rajasthan, India. Apart from practical problems in emasculation and pollination, the conventional hybridization strategy is hampered due to non-availability of pure lines in cumin. RZ 19 was selected for the present study. Air dried seeds of RZ 19 were subjected to gamma rays at 20, 30, 40, 50 and 60 Kr. M(1) generation was raised from the treated seed by dibbling 400 seeds per treatment along with untreated check. No specific morphological mutations were observed in this generation. 50 normal looking plants from each radiation dose and control were advanced to My Out of these 50 plants, 25 were self pollinated to produce 'self pollinated' M(2) progenies in each radiation dose. Seeds harvested from each of the 125 self pollinated and open pollinated progenies were sown in single row plots in RBD in the ensuing year along with control to raise M(2) generation. The control was repeated after every 40 progenies in each block. Observations were recorded on important morphological traits. The progenies in each generation were screened for all possible mutations. Only albino (two) and chlorine (five) types were seen which did not survive beyond seedling stage. Three plants with white flowers were also observed in contrast to pink flowers in RZ 19. Higher estimates of GCV and PCV, heritability in radiation treatments than in control indicated induction of heritable variation. Linear increase in mean values along with the radiation gradient was observed for most of the characters. 30 Kr and 40 Kr are best doses which induced more mutations per dose, 20 Kr dose was ineffective while 60 Kr induced more of seed sterility.