ABSTRACT

Pigeon pea (Cajanus cajan (L.) Millspaugh) is an important legume known for its nutritional value. In the present study, seeds of pigeon pea accessions (Brown and Cream colours) were treated with different concentrations of ethyl methane sulphonate. Seven different concentrations were prepared (0.00 %, 0.01 %, 0.02 %, 0.03 %, 0.04 %. 0.05 %. 0.06 % and 0.07 % w/v). Field experiment was conducted using the same EMS concentrations for M, and M2 generations. The screen house experiment was set up in a complete randomized design and field experiment was set up in a randomized complete block design respectively. Growth data were collected at 3, 6, 9 and 12 weeks after planting in M| and M2 generations whereas yield data were collected at maturity. The results obtained showed that the effect of the mutagen treatments on germination and survival percentages were highly significant (p<0.001). The results showed that 50 % germination was recorded under treatment 0.05 % EMS in the Brown colour accession and 0.04 % EMS in the Cream colour. These concentrations are therefore considered as the LD50 values. The result obtained showed that the treatments significantly improved the vegetative traits of the pigeon accessions in both generations. There were significant differences (P<0.05) between the means of the treated plants when compared to the control plants. Data obtained from the study showed that treatment 0.04 % EMS enhanced vegetative performances in the Brown colour accession whereas, in the Cream accession, 0.03 % EMS induced better performance. The yield performances of the pigeon pea accessions were significantly improved by the mutagen treatments. The result of the analysis of variance showed that plants treated with 0.03 % and 0.04 % EMS produced better yields when compared with the control plants. The results of the proximate, anti-nutrient and mineral compositions ofthe plants in Mi and M2 generations showed that the effect of the mutagen was highly significant (P<0.001) when compared with the control plants. The anatomical studies revealed an increase in the stomatai index in plants treated with 0.01 % EMS on the abaxial surface. The root xylem vessels, thickened more on the higher concentrations (0.03 % - 0.04 % EMS). The cell walls of plants treated with 0.03 % - 0.04 % EMS were thicker with reduced intercellular air spaces. The cortical cells of plants treated with 0.01 % - 0.02 % and the control had thinwalled cells with large intercellular air spaces. Molecular characterization was carried out using a simple sequence repeat marker for diversity and sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDS-PAGE). Ribulose-1,5-biphosphate marker was used in gene sequencing. Higher polymorphic information value was observed in primer CZ681993 (0.7122) with several alleles. The results of the present studies have shown that EMS at 0.03 % and 0.04 % could be used by plant breeders to improve the agronomic characters of pigeon pea. It is therefore recommended that plant breeders employ this mutagen in the breeding program of pigeon pea to create beneficial mutation amidst the ever-increasing human population and food insecurity