VEGETOS Vol. 24 (1) : 89-92 (2011) Gene Action For Yield and its Components in Soybean (Glycine max (L.) Merrill) Shiv Datt*, S. K. Noren1, V. P. Bhadana 2 and P. R. Sharma3 IP&TM Unit, KAB-I, ICAR, Pusa, New Delhi-110012 India 1 College of Post Graduate Studies, CAU, Umiam, Barapani, Meghalay-793 103 India 2 Directorate of Rice Research, Hyderabad India 3 Central Agricultural University, Imphal, Manipur-795 004 India Gene action, interaction and linkage relationship of genes creating continuous phenotypic variation of various metric traits are dedicated to breeding methods. Thus both additive and non-additive components of genetic variance, along their allied characteristics are of great use for plant breeders under different situations. An estimate of additive variance and nonadditive variance provides a measure of how likely particular traits can be selected for or against and that of whether hybridization or a population improvement program. Five generations viz. P1, P2, F1, F2 and F3 were evaluated in experiments under a compact family block design to estimate gene effects for major agro-morphological traits in four soybean single crosses (Bragg x RKS 18, JS 335x RAUS 5 and Bragg x JS 335 and RAUS 5 x Birsa Soy 1). The results showed additive gene effects that determined the inheritance of agromorphological traits viz. days to 50 percent flowering, days to maturity, plant height and harvest index. Dominance gene action was critical in determining the yield. Duplicate epitasis was significantly important in inheritance of most traits studied. On the basis of results obtained from the present investigation, it is suggested that these major quantitative traits in the desirable genotypes play a major role in the improvement of high yielding varieties of soybean through exploitation of additive and non-additive variances. Keywords: gene action, gene effects, agro-morphological traits, soybean INTRODUCTION Genetic studies are conducted to determine if a trait is heritable, how many genes are involved and the possible genetic relationships among genes from different sources with similar phenotypes (Liu, 1997). Once the inheritance of the gene(s) controlling a certain trait is understood, this information can be used to further enhance the crop in terms of yield improvement, pest resistance, or many other vital characteristics. Determining the gene effects and their interaction controlling various agro-morphological traits in soybean and their inheritance will expand the understanding of the genetics of this crop for further applications. The objective of the present investigation is to study the nature and magnitude of gene effects governing the yield and components. Most of the earlier studies conducted on nature and magnitude of genetic variation in soybean are based on diallele, partial diallele * Corresponding author email: shivdatts@rediffmail.com set and gca/sca analysis with the assumption that the epistasis is negligible or absent. The results of the studies indicated that epistasis plays a significant role in the inheritance of yield and its component characters in soybean. Thus the assumption of absence of epistasis may not hold true suggests some breeding methods may not be appropriate for the genetic improvement of these characters hence, in the present investigation, an efforts has been made to find out the inheritance of yield and its attributes for their further utilization in the breeding program. MATERIAL AND METHODS Present investigation was carried out at Central Agricultural University, Imphal during the kharif season of 2006-2007. Five generations namely P1, P2, F1, F2 and F3 of each of four crosses viz., Bragg x RKS 18, JS 335 x RAUS 5 and Bragg x JS 335 and RAUS 89 Shiv Datt et al. Table 1. Scaling tests and gene action for different agro-morphological traits in crosses of soybean Sl. N o. Characters Scales C Genetic components D m d h Days to 50% flowering -18.36* 15.74** 44.23** 2. Days to full maturity -7.10* -9.21** 123.05** 4.65** 3. Plant height(cm) 80.20* 21.03 188.67** 4. Number of pods/plant 78.22* 56.16** 180.92** * ** -17.63** 6.01* Duplicate 0.25 -4.51* 3.21 Complimentary -91.10** 21.08 -185.18** -80.25 Duplicate -57.12** 20.8 -138.32** -28.63 Duplicate 4.21 Duplicate Harvest index (%) -6.14 12.25** 27.24** 8.97** -5.68** 24.58** -7.84 Complimentary 7. Seed yield /plant -0.24* -0.008 0.33** 0.15** -2.90** 0.22** 0.25 Duplicate -0.90 -10.05** 1.98 Duplicate -1.861 -0.461 10.98 5.42 17.61 ** 6. ** -4.12 * -7.85 ** 7.65 ** Dry matter weight/plant(g) Oil per cent 8.86 l 5. 8. -6.01 ** i Bragg x RKS 18 -10.85** -3.98** 1. Non allelic interaction Bragg x JS 335 1. Days to 50% flowering 10.28* -1.85 47.63** -0.94** 4.21** 0.65 -15.23** Duplicate ** -0.31 1.98 0.96 -0.79 Duplicate 2. Days to full maturity -3.0 -3.25 124.0 3. Plant height(cm) -6.23 -4.32 64.28** -0.18 1.95 1.24 2.69 Duplicate 4. Number of pods/plant 2.25 6.32* 76.21** 6.53** -3.06 9.37** 5.18 Complimentary 5. Dry matter weight/plant(g) -0.02 -0.21** 0.61** -65.35** 0.18** 0.15** -0.32** Duplicate 6. Harvest index (%) -0.52 29.63** 42.25** 0.35 -0.21** -19.6** 39.54** Complimentary 7. Seed yield /plant -0.81 2.31* 22.14** -0.15 -0.62 -1.68* 3.95 Complimentary 8. Oil per cent -2.51 0.72 17.21** 0.25 0.35 -0.28 4.16* Complimentary 1. Days to 50% flowering 9.28* -2.85 45.66** -0.85** 3.68** 0.58 -16.13** Duplicate ** -0.42 2.03 0.94 -0.76 Duplicate Duplicate RAUS 5 x Birsa Soy 1 2. Days to full maturity -4.0 -4.55 122.0 3. Plant height(cm) -7.33 -5.62 66.38** -0.21 2.95 2.24 3.69 4. Number of pods/plant 3.25 5.22* 74.21** 5.63** -4.06 8.37** 6.18 ** 0.71 ** 0.18 ** Complimentary -0.06 -0.31 6. Harvest index (%) -0.62 30.63** 43.25** 0.45 -0.25** -20.6** 38.54** Complimentary 7. Seed yield /plant -0.91 3.51* 22.14** -0.15 -0.62 -1.68** 3.95 Complimentary 8. Oil per cent -3.51 0.64 18.11 0.45 -0.38 1. Days to 50% flowering 5.06 -3.86** 46.12** 0.95** ** * 4.03** 5.14** -3.12 -6.21 -0.27 ** Dry matter weight/plant(g) 0.30 0.28 ** 5. ** -64.25 ** 3.16 * Duplicate Complimentary JS 335 x RAUS 5 -11.10** Duplicate 14.25** Duplicate 2. Days to full maturity -8.02 3.45 124.1 3. Plant height(cm) 9.65 27.42** 63.14** 7.36** -1.28 -2.85 23.38** Complimentary 4. Number of pods/plant 1.63 6.45 71.20** 8.04** 7.33** 11.20** 7.45 Duplicate 3.67** -6.12** Duplicate ** ** -0.26 4.02 16.97** -13.65** -17.35 Duplicate 0.24** 0.19** 0.15 Duplicate -0.21 -1.09* -0.23 Complimentary 5. Dry matter weight/plant(g) -0.51 -0.38 6. Harvest index (%) 40.12 28.41** 48.20** -0.51 7. Seed yield /plant -1.82 -6.45** 0.56** -0.007 8. Oil per cent -0.32 -0.51 22.41 -0.95 ** 17.52 ** -0.68 ** ** 90 Gene Action in Soybean (Glycine max) 5 x Birsa Soy 1 were evaluated in a compact family design with three replications during the kharif 200708. Each plot had three rows of 3m length, spaced at 45 cm apart, with a plant to plant distance maintained at 10 cm. The standard agronomic practices were followed to raise a healthy soybean crop. Ten competitive plants from generations namely P 1, P2 and F1 and 40 in F2 and 50 in F3 were randomly selected from each replication in each plot to record observations on major quantitative traits viz., plant height, days to 50 per cent flowering, days to maturity, number of pods per plant, seed yield per plant, dry matter weight per plant, harvested index and oil content. Data were subjected to individual scaling tests viz., C and D to detect the presence of epistasis following Mather (1949). The gene effects were estimated by the five parameter model as proposed by Haymen (1958). RESULTS AND DISCUSSION The significant gene interaction effects and variance from different crosses was estimated for various agro-morphological and quantitative traits in view of the great value of epistatic variation in inheritance. Presence of significant and highly significant estimates of either one or two scaling tests were found for all traits studied except oil content in cross (Bragg x RKS 18), C scale for days to 50 per cent flowering and D scale for most of the traits was found significant in Bragg x JS 335. In case of JS 335 x RAUS 5, D scale was found significant for number of traits viz., plant height, days to 50 per cent flowering, days to full maturity, seed yield per plant and harvest index. Table 1 indicates the presence of epistatic variation in the inheritance of various quantitative traits studied. Maloo and Nayer (2005) also found significant at least one or two scales for days to 50 per cent flowering, days to full maturity, yield per plant, harvest index, number of pods per plant and plant height. The estimates of mean (m) were highly significant for all the traits studied in all crosses. Highly significant value of „m‟ from generation mean analysis in all the crosses showed that the five generations differed from each other significantly. Additive (d) component was predominantly in the inheritance of all the traits in the intervarietal crosses Bragg x RKS 18, Bragg x JS 335, JS 335 x RAUS 5 and RAUS 5 x Birsa Soy 1, revealed that selection in early segregating generations would be effective for obtaining genetic gain of these characters. The dominance gene effect (h) was significant and greater in magnitude than the additive effect (d) for days to 50 per cent flowering and harvest index in Bragg x JS 335 and JS 335 x RAUS 5 and days to 50 percent flowering, harvest index and seed yield per plant in Bragg x RKS 18 and RAUS 5 x Birsa Soy 1, indicating a predominant role of dominance gene action in controlling these traits in soybean. Similar results were found as additive and dominance effects and variance were important in genetic determination of seed yield and its componets (Sharma et. al. 1993). Among the digenic interaction effects additive x additive was significant for all the traits in Bragg x RKS 18 and Bragg x JS 335 and days to maturity, number of pods per plant in JS 335 x RAUS 5 and number of pods per plant, dry matter weight per plant, harvest index and oil content RAUS 5 x Birsa Soy 1. Dominance x dominance type of interaction also showed greater effects in the present study. It was found significant for plant height JS 335 x RAUS 5, days to 50 per cent flowering along with oil content in RAUS 5 x Birsa Soy 1 and 50 per cent flowering in Bragg x RKS 18 and Bragg x JS 335. Singh et al. (2010) also found significant interaction effects of additive x additive and dominance x dominance for days to 50 percent flowering, plant height, days to maturity and number of pods per plant. Complimentary epistasis was observed for number of pods per plant, dry matter weight per plant, harvest index and oil per cent in JS 335 x RAUS 5 and plant height and oil content in RAUS 5 x Birsa Soy 1 and days to maturity, dry matter weight per plant in Bragg x RKS 18 and Bragg x JS 335, which appeared to be desirable and would be helpful in further improvement of these traits. Opposite and significant signs of „h‟ and „l‟ components indicated the importance of duplicate epistasis in almost all the crosses for various quantitative characters. Hence there is a hindrance in selection as well as complex nature of inheritance for improvement of these traits. In this situation reciprocal recurrent selection is likely to be useful for effective utilization of both types of additive and non-additive gene effects simultaneously. The significant complimentary epistasis was also observed for yield other quantitative traits like number of pods per plant, dry matter weight per plant, harvest index and oil per cent by Singh et al. (2010). Considering overall results, it is apparent that most of the characters in either of the crosses were found to be under the control of additive and nonadditive gene effects coupled with duplicate type of epistasis. This indicated that heterosis breeding and recurrent selection would be more effective for the improvement of most of the characters. The duplicate epistasis for most characters showed their complex nature of inheritance. Therefore, breeding strategies should be designed accordingly to get desired results. Use of recurrent selection has been suggested to improve the traits when both additive and non-additive gene effects are involved in expression of the traits. REFERENCES Liu KS (1997). Soybeans: chemistry, technology and utilization. Chapman & Hall, New York. Maloo SR and Nair Sandeep (2005). Generation mean analysis for 91 Shiv Datt et al. seed yield and its components in soybean. Ind J Genet 65(2): 139140. Maloo SR and Sharma SC (2007). Combining ability for oil and protein content in soybean. Ind J Genet 67(2):206-208. Rahangdale SR and Raut VM (2002). Gene effects for oil ather quantitave traits in soybean. Ind J Genet 62(4): 322-327. Sharma SK, Mehta H and Sood VK (1993). Effects of cropping systemes on combining ability and gene action for grain yield and its components. Field Crop Res 34 (1): 15-22. Singh RK, Puspendra Singh K and Bhardwaj PM (2010). Gene effects for major quantitative traits in soybean (Glycine max L. Merrill). Soybean Genet News 37. www.soygenetics.org/articlefiles. Raut VM, Taware SP and Halvanker GB (2000). Gene effects for quantitative characters in soybean crosses. Ind J Agri Sci 70(5) : 334-335. 92