Genetic Variability, Correlation and Path Analysis in Iranian Onion Landraces

Document Type : Research Article

Author

• Seyyed Ali Mousavizadeh

East Azarbaijan Agricultural and Natural Resources Research and Education Center

https://doi.org/10.22067/jhorts4.v33i1.65006

Abstract

Introduction: Information on nature and magnitude of present variability in a population is an important pre-requisite for starting any breeding program. Moreover, the knowledge about correlations among various characters and further partitioning them into direct and indirect effects is a rational approach to understanding such a relationship which is helpful for multiple trait selections. The present study was undertaken to determine the genetic variability and heritability of important economic characters, interrelationships among them and their direct and indirect effect on yield in Iranian onion landraces.
Materials and Methods: Seeds of twenty landraces were planted using a randomized complete block design with three replications in East Azarbayjan Agricultural and Natural Resources Research and Education Center for two years. Thirty plants were selected at random in each plot to record the observations on yield/plant, leaf length, number of leaves/plant, bulb length, bulb diameter, number of centers, number of edible layers, bulb dry matter and shape index. Broad-sense heritability, expected genetic advance, genetic variability, correlation coefficient, and path coefficient analysis calculated.
Results and Discussion: Analysis of variance showed significant effects for all studied traits. Therefore, sufficient genetic variability exists among the onion landraces.
The bulb yield per plant had the utmost phenotypic and genotypic coefficients of variation (PCV and GCV) (27.81% and 24.27%, respectively). This shows the prevalence of greater genetic variability among the genotypes which offers good opportunities for crop improvement through selection. Medium PCV and GCV were displayed in bulb diameter, number of leaves/plant, leaf length, number of center and shape index. But number of edible layers and bulb dry matter showed low GCV and PCV indicating less scope of selection as they are under the influence of environment.
The estimates of phenotypic coefficients of variation were higher than their corresponding genotypic coefficients of variation for all the traits. That might be due to interaction of genotype with environment to the same degree or other denoting environmental factors influencing the expression of these traits. A high degree of disparity between PCV and GCV for most of the traits showed their susceptibility to environmental fluctuations.
In present study, the estimates of broad-sense heritability ranged from 16% for number of edible layers to 88% for shape index. Heritability estimates were very high for bulb diameter, leaf length, and number of centers and shape index, indicating the possibility of success in selection. Heritability estimates were relatively high for yield/plant, bulb length and number of leaves/plant. In addition, moderate heritability estimate was observed for bulb dry matter. On the other hand, low heritability estimates was also observed for number of edible layers indicating the limited scope for improvement of this trait through selection.
The expected genetic advance expressed as a percentage of the mean by selecting the top 5% of the accessions, varied between 1.6% for number of edible layers to 43.55% for yield/plant. Genetic advance as percentage of mean was maximum for yield/plant followed by number of centers, shape index, leaf length, bulb diameter, number of leaves/plant and bulb length. Genetic coefficient of variation, heritability, and genetic advance were high in yield/plant. Therefore, yield/plant could be useful basis for selection.
In most traits, the genotypic correlation coefficients were higher than the phenotypic correlation coefficients which indicated the inherent association among various characters independent of environmental influence.
Bulb-yield/plant showed significant positive correlation with leaf length, leaf number, bulb diameter and bulb length at phenotypic and genotypic levels. So, improvement of leaf length, leaf number, and bulb diameter and bulb length traits could improve the capacity of the plants to synthesize and translocate photosynthates to the bulb.
The path analysis showed that bulb diameter has the largest positive direct effect on bulb-yield/plant. The indirect effect of length of leaves on onion yield through bulb diameter was considerable. Accordingly, selection of plants with larger leaf length and bulb diameter could be suitable for breeding onion for higher yield. The presence of negligible residual effect (0.06) indicated that most of the important traits contributing to yield were included in the path analysis.
Conclusions: Results showed that potential of onion landraces with high genetic diversity in selection for development of cultivars with favorable agronomic and market traits is high. The high genetic coefficient of variation, heritability, and genetic advance were found in yield/plant. Therefore, yield/plant could be useful basis of selection. In addition, the path analysis showed that selection of plants with larger leaf length and bulb diameter could be suitable for breeding onion for higher yield.

Keywords

• Bulb diameter
• Diversity
• Genetic advance
• Leaf length
• yield

20.1001.1.20084730.1398.33.1.3.9

References

1- Azimi, M., Massiha, S., Moghaddam, M. and Valizadeh, M. 2000. Genetic variation of onion local varieties in Iran. Journal of Science and Technology of Agriculture and Natural Resources, 4:15-26. (in Persian with English abstract).

2- Barta, S. K., Kallo, G. and Singh, B. 1983. Combining ability, heterosis and analysis of phenotypic variation in onion. Haryana Journal of Horticultural Sciences, 12:119-119.

3- Brewster, J. L. 1994. Onions and Other Vegetable Alliums. CABI, Wallingford, Oxon, UK.

4- Burton, G. W. 1952. Quantitative inheritance in grasses. Proc.6th Int. Grassland Congr, 1:277-283.

5- Burton, G.W., and Devane, E. M. 1953. Estimating heritability from replicated clonal material. Agronomy Journal, 45: 478-481.

6- Darabi, A. 2016. The Study of Effect of Planting Date and Density on Marketable Yield and Bulb Characteristics of an Onion Population from Behbahan. Journal of Crop Production and Processing, 5(18): 301-314.

7- Degewione, A., Alamerew, S. and Tabor, G. 2011. Genetic variability and association of bulb yield and related traits in shallot (Allium cepa Var. Aggregatum DON.) in Ethiopia. International Journal of Agricultural Research. 6(7): 517-536.

8- Dehdari, A., Rezai, A., and Mobli, M. 2001. Morphological and agronomic characteristics of landrace varieties of onion (Allium cepa L.) and their classification. Journal of Science and Technology of Agriculture and Natural Resources, 5(2): 109-124. (in Persian with English abstract).

9- Dewangan S.R. and Sahu G.D. 2014. Genetic variability, correlation and coefficient analysis of different Kharif onion genotypes in Chhattisgarh plains. Agricultural Science Digest, 34 (3): 233 – 236.

10- Doweker, B. D. 1990. Onion breeding. pp. 215-232. In: Rabinowith, H. D., and Brewester, J. L. (eds.).Onions and Allied Crops, Vol. 1. Bota Raton, CRC Press Inc.

11- Falconer, D. S. 1989. Introduction to Quantitative Genetics. 3rdEdn. Longman Scientific and Technical, New York, 438 pp.

12- Galmarini, C. R., Goldman I. L. and Havey, M. J. 2001. Genrtic analyses of correlated solids, falvor, and health-enhancing traits in onion (Allium cepa L.). Molecular Genetic and Genomics, 256: 543-551.

13- Golani, I. J., Vaddoria, M. A. Mehta, D. R., Naliyadhara, M. V., and Dobariya, K. L. 2006. Analysis of yield components in onion. Indian Journal of Agricultural Research, 40(3): 224-227.

14- Haydar A., sharker, N., Ahmad, M. B., Hannan M. M., Razvy, M. A., Hossain, M., Hoque A., and Karim, R. 2007. Genetic variability and interrelationship in onion (Allium cepa L.). Middle-East Journal of Scientific Research, 2(3-4): 132-134.

15- Hosamani, R. M., Patil, B. C., and Ajjappalavara, P. S. 2010. Genetic variability and association among bulb yield and yield-related traits in onion (Allium cepa L.). Karnataka Journal of Agricultural Sciences, 23: 302-305.

16- Johnson, C. E., and Hernandez, T. P. 1980. Heritability studies of early and total yield in tomatoes. Horticultural Science, 15:280-285.

17- Johnson, H. W., Robinson H. F. and Comstock, R. E. 1955a. Estimates of genetic and environmental variability in soybean. Agronomy Journal, 47:314-318.

18- Johnson, H. W., Robinson H. F. and Comstock, R. E. 1955b. Genetypic and phenotypic correlations in soybeans and their implication in selection. Agronomy Journal, 47:477-483.

19- Kalloo, J. C., Pandey, S. C., Lal S., and Pandita, M. L. 1982. Correlation and path analysis Studies in onion (Allium cepa L.). Haryana Journal of Horticultural Sciences, 11: 97-97.

20- Kassahun, T. 2006. Variability and association among bulb yield and related traits in garlic (Allium sativum L.). M. Sc. Thesis, School of Graduate Studies of Alemaya University.

21- Korla, B. N., Singh A. K., and Kalia, P. 1981. Genetic variability in garlic. Haryana Journal of Horticultural Sciences, 10:77-80.

22- Lee, W. S., Kim, Y. C. and Lee, B. C. 1977. Varietal characters and genetic correlations in different ecotypes of garlic. Korean Journal of Breeding Science, 9: 149-157.

23- Mahantesh, B., Harshavardhan, M., Tippesha, D. Sajjan, M. R. P. and Janardhan, G. 2007. Correlation studies in onion genotypes in kharif season under irrigated and rain fed situations. Asian Journal of Horticulture, 2: 71-74.

24- Mc Collum, G. D. 1996. Heritability and genetic correlation of some onion bulb traits.Journal of Heredity, 57: 105- 110.

25- Mcferson, J. R., Walters, T. W., and Eckenrode, C. J. 1996. Variation in Allium spp. Damage by onion maggot. Horticultural Science, 31: 1219-1222.

26- Melke, A., and Ravishankar, H. 2006. Variability and association among bulb yield and yield-related traits in onion (Allium cepa L.). Tropical Agriculture (Trinidad), 83: 112-119.

27- Mohanty, B. K. 2004. Genetic variability and path analysis in onion. Indian Journal of Agricultural Research, 38(1): 65-68.

28- Mohanty, B. K., 2001. Genetic variability, inter-relationship and path analysis in onion. Journal of Tropical Agriculture, 39: 17-20.

29- Mohanty, B.K., and Prusti, A. M. 2001. Performance of common onion varieties in Kharif seasons. Journal of Tropical Agriculture, 39:21-23.

30- Morsy, M. G., Marey, R. A., and Geries, L. S. M. 2011. Genetic variability, heritability, genetic advance and phenotypic correlation in some onion varieties. J. Agric. Res. Kafer El- Sheikh Univ., 37(1):57-71.

31- Mulungu, L.S., Nchimbimsolla, S.O.W.M., Reuben, S., Misangu, R. N., Mbilinyi, L.B. and Macha, M. M. 1998. Performance of nine exotic and local onion (Allium cepa L.) genotypes grown under a dry season tropical condition at Morogoro, Tanzania: 1. Yield and its components. South African Journal of Science, 94: 451-454.

32- Pandian, I. R. S., and Muthukrishnan, C. R. 1982. Correlation and path coefficient analysis in onion (Allium cepa L.) seed to bulb generation. South Indian Horticulture, 30: 22-24.

33- Pramoda, H. P., and Gangaprasad, S. 2007. Biometrical basis of handling segregation population for improving productivity in onion (Allium cepa L.). Asian Journal of Horticulture, 3: 278-280.

34- Rahman, M. A., Saha, S. R., Salam, M. A., Masum, A. S. M. H. and Chowdhury, S. S. 2002. Correlation and path coefficient analysis in onion (Allium cepa L.). Journal of Biological Sciences, 2 (8): 531-532.

35- Raymond, A. T. G. 1999. Vegetable seed production. CAB International publication, UK.p.328.

36- Robinson, H. F., Comstock, R. E., and Harvey, P. M. 1951. Genotypic and phenotypic correlations in corn and their implications in selection. Agronomy Journal, 43: 282-287.

37- Shigyo, M., and KiK, C. 2008. Onion. pp. 121-162. In: Prohens, J., and Nuez, F. (eds.) Vegetables: handbook of plant breeding. Vol. 2, Springer Verlag, Berlin.

38- Shimeles, A., 2000.Study on flower and seed production potential and association of characters with seed yield in onion (Allium cepa L.). M.Sc. Thesis, School of Graduate Studies. Alemaya University.

39- Singh, R. P. 1981. Genetic evaluation and path analysis in onion. Madras Agricultural Journal, 68:61-80.

40- Singh, R. K., Dubey, B. K., Bhonde, S. R. and Gupta, R. P. 2010. Estimates of genetic variability and correlation in red onion (Allium cepa L.) advance lines. Indian Journal of Agricultural Sciences, 80(2): 160-163.

41- Sivasubramanian, S., and Menon, M. 1973. Heterosis and inbreeding depression in rice. Madras Agricultural Journal, 60: 1139.

42- Vavidel, B., Muthukrishnan, C. R., and Irulappan, I. 1981. Association of characters between yield and yield components in Aggregatum onion (Allium cepa L.). South Indian horticulture, 29: 227- 228.

43- Yaso, I. A. A. 2007. Performance and genetic parameters for six onion genotypes in Nubaria area. Egyptain Journal of Plant Breeding, 11 (3): 307-318.