Mutagenic effectiveness and efficiency in Cowpea

Abstract

Mutation induction is considered as an effective way to enrich plant genetic variation, particularly for traits with a very low level of genetic variation. In the present study, mutagenic effectiveness and efficiency in two morphologically divergent cultivars of cowpea viz., Pusa Komal and Arka Garima were investigated and efficiency was calculated based on pollen sterility (%) and lethality. Seeds were treated with different doses of gamma rays (100, 200, 300, 400, 500 Gy (gray)) and chemical ethylmethane sulphonate (EMS) concentration (0.25%, 0.30%, 0.35%, 0.40%, 0.45%) for 6 h. Untreated seeds were used as control. In general, the mutagen effectiveness and efficiency increased with increasing dosage and then declined. A non-linear effect was seen up with 300 Gy doses of gamma rays in var. Pusa Komal. Dose dependant (more than 200 Gy) linear decline in the effectiveness was observed in Arka Garima. The effectiveness increased with the increase in concentrations of the chemical mutagens till 0.30% in Pusa Komal and 0.35% in Arka Garima and showed a decline. In variety Pusa Komal, mutagenic efficiency decreased at higher dose (lethal) of gamma rays. In case of sterility, the maximum mutagenic efficiency was observed at 100 Gy of gamma rays and 0.25% of EMS. Mutagenic efficiency increased up to 300 Gy dose in case of lethality and 200 Gy for sterility but decreased thereafter in Arka Garima. In case of chemical mutagen, 0.35% treatment proved to be the most efficient concentration for sterility and lethality. Higher efficiency on sterility was observed in both the varieties. Pusa Komal appeared to be more sensitive than Arka Garima