PHYSICAL AND CHEMICAL MUTAGENS IN COWPEA

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1 Legume Res., 36 (1) : 10-14, 2013 AGRICULTURAL RESEARCH COMMUNICATION CENTRE ccjournals.com / indianjournals.com nals.com INDUCTION OF GENETIC VARIABILITY FOR POLYGENIC TRAITS THROUGH PHYSICAL AND CHEMICAL MUTAGENS IN COWPEA [VIGNA UNGUICULATA (L.) WALP] D.P. D.P. Singh 1, S.P. S.P. Sharma, Mohan Lal al 2, B.R. Ranwah and Vimal Sharma ma Department of Plant Breeding and Genetics, Maharana Pratap University of Agricultureand Technology, Udaipur , India Received: Accepted: ABSTRACT An investigation was carried out to estimate the genetic variability induced through physical and chemical mutagens in cowpea.the seed of cowpea variety RC 19 were treated with gamma rays and ethyl methane sulphonate (EMS), in M 2 generation indicating significant differences in the mean value of treated population. The mean values for plant height, number of primary branches, number of pods, number of grains, 100-seed weight and seed yield reduced significantly with increasing concentration of both the mutagens. Protein content and biological yield increase significantly with increasing doses of both the mutagens. The study revealed that magnitude of phenotypic coefficient of variation was distinctly high for plant height, number.. of pods per plant, seed yield per plant, biological yield, harvest index and protein content. Phenotypic coefficient of variation was higher then genotypic coefficient of variation except in protein content for family EMS 0.1 %. The gap between GCV and PCV was narrow which reflect lesser degree of environmental influence on the genotypic variability Key words: Genetic variability, Induced mutations, Protein content, Vigna unguiculata L., Yield components. INTRODUCTION Cowpea [Vigna unguiculata (L). Walp] is an important grain legume crop in India and Asia, adopted to the drought prone semi arid climate. Besides it s used as pulse, vegetable, fodder and green manuring, it is also grown as a cover crop to conserve soil moisture and improve soil fertility. Pulses form an important part of Indian dietary. They are an important source of protein and are essential adjunct to a predominantly cereal based diet and enhance the biological value of the protein consumed. Cowpea is tropical grain legume which plays an important role in developing countries of the tropics and sub tropics, especially in sub Saharan Africa, Asia, Central and South America, and is cultivated over an area of 12.5 million hectare, with an annual production of over 3 million tones world wide (Singh and Yadav, 1991). Because of its high protein content (20-25%), cowpea is referred as poor man s meat. Its young leaves, pods and seeds contain vitamins and minerals which have fuelled its usage for human consumption and animal feeding. Cowpea a most versatile kharif pulse crop because of its smothering nature, drought tolerant characters, soil restoring properties and multipurpose uses( Ashok et al 2010). Most of the crop improvement programmes attempted through conventional breeding methods have exploited only the natural variability available in the germplasm. Selection within local types exercised for a long time, exhausted the natural genetic variability of the crop. Adequate variability is not available in the gene pool to change the plant ideotype or to correct specific deficiency of otherwise outstanding genotypes. Under such circumstances, induced mutagenesis can be efficiently employed as 1 Corresponding author address and R.S.S. and Organic Production Certification Agency, Suratgarh , (Raj.) dp1yash@yahoo.com. 2 Division of Crop Improvement CSSRI, Karnal

2 Vol. 36, No. 1, an alternative to induce the variability in effects. In M 1 generations, observations were morphological and physiological characters. Genetic recorded for plant height (cm), number of primary improvement of a crop primarily depends upon branches per plant, number of pods per plants, extent of genetic variability present in the population. number of grains per pods, 100 seed weight, seed Experimentally induced mutations provide an yield per plant (g) and harvest index (%) were important source of variability. In mutation breeding recorded on ten randomly selected plants in each selection of appropriate mutagen and its dose is most replication, while days to 50% flowering was important for obtaining wide spectrum and high recorded on whole plot basis.. Analysis of variance frequency of desirable mutations. Hence selections was carried out as per formula suggested by (Panse of relatively better responsive genotypes to the and Suikhatme 1978). GCV and PCV were carried mutagen treatment also help in achieving higher out as method suggested by (Burton 1952) and mutagenic efficiency (Mahanasundram et al (Singh and Choudhary 1979).Heritability were and Kharkwal et al.1988). In mutation breeding, it carried out by formula suggested by (Burton and is advocated that induction of viable and potential De-vane 1953). Genetic gains were estimated by mutations in cowpea through treatment of gamma using formula suggested by (Lush 1949). rays and ethyl methane sulphonate, because it is RESULTS AND DISCUSSION convenient and require lesser time than the In M 1 generation, the delay in flowering was conventional breeding particularly when intended recorded at all doses/concentration of the mutagens. variety is an adopted one and is deficient in few Both the mutagens resulted in the reduction in mean characters which are governed by major of almost all yield contributing traits and pollen genes(hepziba and Subramanaian 1994 and stainability (%). Pandey and Pawar 2004).The present investigation was undertaken to induce viable mutations in All above effects are considered as direct quantitative and qualitative traits on the most effects of mutagenic treatments and cannot be commonly grown variety of cowpea viz; RC-19 ascribed to any genetic alterations. The heritable which could be utilized directly or introduced into changes can be measured in M 2 our cowpea improvement program. Therefore, to study the mutagenic effects, particularly induction of variability, the M MATERIALS AND METHODS 2 generation was raised by advancing the individual normal appearing M 1 Three hundred dry uniform and healthy plants. In order to maintain uniformity in number of seeds were exposed to 60 Co gamma radiations(0, progenies, only those treatments were advanced in 10, 20, and 30 kr) treated at BARC Mumbai and which a minimum of 20 normal appearing plants ethyl methane sulphonate (0.1, 0.2, and 0.3%) and were available. Treatments advanced to M 2 sown in two rows of three meters length in generation were control, -rays 10, 20, 30 kr and randomized block design with three replications. Spacing between rows and plants within rows were EMS 0.1 and 0.2 per cent. Hence there were six 45 and 10 cm, respectively in M 1 The families and each family comprised of twenty M 2 generation was raised from individual M 1 plants progenies. following plant to progeny row in compact family A comprehensive consideration of the data block design with three replications. These for quantitative characters in M 2 generation experiments were conducted at the research farm, indicating significant differences in the mean value Maharana Pratap University of Agriculture and of treated population. The mean values for plant Technology, Udaipur during Kharif 2004 and Kharif height, number of primary branches per plant, Those M 1 plants which were normal appearing number of pods per plant, number of grains per pod, without any sterility effects of mutagens were 100-seed weight and seed yield per plant reduced randomly selected for raising M 2 progenies. This was significantly with increasing concentration of both done, to ensure that greater proportion of variability the mutagens (Table 1). Protein content and exhibited in M 2 progenies of a given treatment biological yield per plant increase significantly with (family) is due to mutagens and not due to sterility increasing doses of both the mutagens for almost

3 12 LEGUME RESEARCH TABLE 1: Estimates of mean, range and coefficient of variantion for different characters in RC-19 variety of cowpea in M 2 Treatment/ Days to Plant No. Of primary No. of pods No. of 100- seed Seed yield/ Biological yield/ Harvest Protein Family 50% height (cm) branches/ plant /plant grains/ pod weight (g) Plant (g) \plant (g) index (%) content (%) flowering M C M C M (31.0- CONTROL R 33.67) ( ( ) ( ) 53.77) (9.37- ( ) ( ) ( ) 11.13) ( ) ( ) ( γ-rays 10 kr R 35.33) ( ( ) ( ) 51.27) (9.30- ( ) ( ) ( ) 11.73) ( ) ( ) ( ( ( ) ( ) (9.37- γ-rays 20 kr R 36.33) 45.87) 10.60) 39.03) 22.77) C M ( ) ( ) ( ) ( ( ( ( ( ) ( ) (8.60- γ-rays 30 kr R 38.33) 48.33) 12.20) 36.33) 22.77) C M ( ) ( ) ( ) ( ( ( ( ( ) ( ) (8.50- EMS 0.1 % R 35.00) 47.50) 10.97) 42.97) 22.10) C M ( ( ( ) ( ) ( ) ( ( ( ) ( ) (8.67- ( ) ( ) ( ) ( ( EMS 0.2% R 37.00) 51.80) 11.03) 38.43) 22.67) C CD 5% C= coefficient of variance, M= Mean and R= Range

4 Vol. 36, No. 1, TABLE 2: Estimates of various variability parameters in RC-19 variety of cowpea in M 2 Characters/family GCV (%) PCV (%) Heritability (%) G.G. (%) Plant height (cm) ã-rays 30 kr seed weight (g) ã-rays 30 kr Biological yield per plant (g) EMS 0.1% EMS 0.2% Protein content (%) ã-rays 10 kr ã-rays 20 kr EMS 0.1% EMS 0.2% all the families (Chavan et al 2000, Hepziba and Subramanaian 1994, Singh and Yadav 1991 and Odeigah et al 1998). The magnitude of coefficient of variation was distinctly high for plant height, number. of pods per plant, seed yield per plant, biological yield, harvest index and protein content (Kharkwal et al 1988, Pawar and Pandey 2001 and Pandey and Pawar 2004). This may enable us to speculate that these characters are governed by relatively more number of genes then those which showed less coefficient of variation. The coefficient of variation was highest for EMS 0.2% as compare to other treatments. Variability parameters like genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), heritability and genetic gain work calculated for all those families which exhibited significant progeny differences. The magnitude of, phenotypic coefficient of variation were higher then genotypic coefficient of variation except in protein content for family EMS 0.1 % (Table-2). The gap between GCV and PCV was narrow which reflect lesser degree of environmental influence on the genotypic variability (Chavan et al 2000). Assessment of variance has been the most dependable statistical measure to find the mutagenic effect on the polygenes. The genotypic coefficient of variation provides a mean to study the genetic variability generated in quantitative characters (Johnson et al 1955, Ashok et al 2010, Narsinghni and Kumar 1976 and Wani 2009). The response of mutagens as measured by the magnitude and the nature of variability varied from character to character. Three progeny for biological yield per plant in family 30 kr and two progenies in EMS 0.2% for protein content, twenty progenies in each 20 kr,30 kr and EMS 0.2% families were superior than control. Eleven progenies in EMS 0.1 % and three progenies in -rays 10 kr were found superior than control and identified for high protein content. Hence, for improving the quality traits in cowpea, these progenies should be carried forward for isolating high protein mutants also. REFERENCE Ashok K. V., Kumari U., Vairam M. and Amutha R. (2010). Effect of physical mutagen on expression of characters in arid legume pulse cowpea (Vigna unguiculata (L.) Walp.). Electronic Journal of Plant Breeding, 1(4): Burton G.W. (1952). Quantitative inheritance in grasses. Proc. 6th Int. Grassland Conf. 1: Burton G.W. and De-Vane E.M. (1953). Estimation of heritability in tall fescue. Agron J. 45: Chavan, A.A., Patil, V.D. and Pawar, R. B. (2000). Induced mutations in mung bean- variety BM-4. DAE Symposium, BRNS, Mumbai, pp Hepziba,S.J. and Subramanaian, M. (1994). Gamma rays induced variability in blackgram (Vigna mungo L. Heper. Annals of Agril. Res, 15: Johnson, H.W.,. Robinson H.F and. Comstock R.E. (1955). Estimates of genetic and environmental variability in soybean. Agron. J., 47: Kharkwal, M. C., Jain, H.K. and Sharma,B. (1988). Induced mutation for improvement of chick pea, lentil, pea and cowpea. In: Proceding of Workshop on Improvement of Grain Legume Production Using Induced Mutations, Pullman, Viena, pp

5 14 LEGUME RESEARCH Lush J.L. (1949). Heritability of quantitative characters in farm animals. Heridates (Suppl.). 35: Mohanasundram, M., Thamburaj, S. and Natrajan S. (1999). Studies on induced mutagenesis in vegetable cowpea (Vigna unguiculeta L. walp). South Indian Hort., 47: Narsinghni, V.G. and Kumar, S. (1976). Mutagenic studies in cowpea. Indian J. Agric Science: 46: Odeigah, P.G.C., Osanyinpeju, A O. and Myers, G.O. (1998). Induced mutations in cowpea [Vigna ungiculata (L.) Walp] Rev. Biol. Trop.v. 46 n. 3 San jose set. Pandey. R.N. and Pawar, S.C. (2004). Mutation breeding in cowpea in Indian. (Eds. Kumar, D. and Singh,N.B.) Scientific Publisher, Jodhpur, Chapter-7. Panse V.G.and Sukhatme P.V. (1978). Statistical Method for Agriculture Research Worker.ICAR New Delhi Pawar, S.E. and Pandey, R.N. (2001). Role of induced mutation in pulse crops improvement in India. In: proceeding of National Symposium on Pulses for Sustainable Agricultural and Nutritional Security, Kanpur, pp Singh R.K. and Choudhary, B.D. (1979). Biometrical Methods in Quantitative Genetics Analysis, Kalyani Pub., New Delhi. Singh, V.P and R.D.S. Yadav. (1991). Induced mutations for qualitative and quantitative traits in greengram. J.Genet. and Breed., 45: 1-5. Wani, M. R. and Khan, S. (2006). Estimates of genetic variability in mutated populations and scope of selection for yield attributes in Vigna radiate (L.)Wilczek. Egyptian J. of Bio. 8: pp 1-6. Wani, A. A. (2009). Mutagenic effectiveness and efficiency of gamma rays, Ethyl methane sulphonate and their combination treatment in chickpea (Cicer arietinum L.). Asian J. of Plant Sci. 8: 1-4.