Analysis of correlation coefficients between grain yield and yield components in cowpea genotypes under normal and drought stress conditions

Document Type : Research Paper


1 Former Graduate Student, University College of Agriculture and Natural Resources, University of Tehran, Karaj

2 Professor, University College of Agriculture and Natural Resources, University of Tehran, Karaj


In order to deliberate correlation coefficient between grain yield and yield components among 31 cowpea genotypes under normal irrigation (non-stress) and drought stress (water withholidng after flowering stage until maturity) an experiment was performed in a randomized complete block design (RCBD) with three replications at research field of University of Tehran located at Karaj during 2011-2012 growing season. The traits measured comprised of plant height, branches number per plant, pods number per plant, seeds per pod, biological yield, grain yield per plant and 100 seed-weights. Results showed that under both irrigation regimes, biological yield and pods number per plant were highly correlated with grain yield. Stepwise regression analysis revealed that biological yield and pods number per plant had the highest effect on grain yield of cowpea genotypes under both irrigation conditions. Path analysis showed that the highest direct positive effect of biological yield and pods number per plant on grain yield under both conditions. Therefore, in breeding programs, to boosting grain yield in cowpea genotypes, it is better that the selection to be based on the biological yield and number of pod per plant traits.


  1. Adams, M. W. (1982). Plant architecture and yield breeding. Iowa State Journal of Research. 56(3), 225-254.
  2. Aggarwal, V. D. & Singh, T. D. (1973). Genetic variability and interrelation in agronomic traits in kidney bean. Journal of Agricultural Science, 43, 845-848.
  3. Aggarwal, V. D., Natare, R. B.  & Smithson, J. B. (1982). The relationship among yield and other characters in vegetable cowpea and the effect of different trellis management on pod yield. Trop Grain Leg Bull, 25, 8-14.
  4. Ahmad, F. E. & Suliman, A. S. H. (2010). Effect of water stress applied at different stages of growth on seed yield and water-use efficiency of Cowpea. Agriculture and Biology Journal of North America, 1(4), 534-540.
  5. Altinbas, H. (1993). A study to determine components effecting seed yield in cowpea. Mancilik Dergisi, 17, 775-784.
  6. Ariyo, O. J., Pkenova, M. E.  & Fatokun, C. A. (1986). Plant character correlations and path analysis of pod yield. Euphytica, 36, 677-686.
  7. Bastos, E. A., Nascimento, S. P. Silva, E. M. Filho, F. R. F. & Gomide, R. L. (2011). Identification of cowpea genotypes for drought tolerance. Revista Ciência Agronômica, 42(1), 100-107.
  8. Blum, A. (2011). Plant breeding for water-limited environments. Springer. 258 pp.
  9. Boutraa, T. & Sanders, F. E.  (2001). Infuence of water stress on grain yield and vegetative growth of two cultivars of bean (Phaseolus vulgaris L.). J Agronomy & Crop Science, 187, 251-257.
  10. Chalyk, L.V., Balashov, T. N. & Zuchenka, A. A. (1984). Relationship between yield in french bean varieties and its structural components. Biology Bulletin, 29(1), 53-55.
  11. Chung, J.H. & Goulden, D. S. (1971). Yield Components of haricot beans (Phaseolus vulgaris L.) growth at different plant densities. New Zealand Journal of Agricultural Research. 14, 227-234.
  12. Dimova, D. & Svetleva, D. (1992). Inheritance and correlation of some quantitative characters in French bean relation to increasing the effectiveness of Selection. Indian Journal of Genetics & Plant Breeding. 63(3), 344.
  13. Duarte, R. A. & Adams, M. W. (1972). A path coefficient analysis of some yield component Interrelations in field bean (phaseolus vulgaris L.). Crop Science, 12, 579-582.
  14. Ehlers, J. D. & Hall, A. E. (1997). Cowpea (Vigna unguiculata L. Walp.). Field Crops Research,53, 187-204.
  15. Habibi, G. R. & Bihamta, M. R. (2007). Study of seed yield and some associate characteristics in pinto bean under reduced irrigation. Pajouhesh & Sazandegi, 74, 34-46. (In Farsi).
  16. Honarnejad, R. (2002). Study of correlation between some quantitative traits and grain yield in rice using path analysis. Iranian Journal of Crop Sciences, 4(1), 25-35. (In Farsi).
  17. Kumaga, F. K., Adiku, S. G. K. & Ofori, K. (2003). Effect of post-flowering water stress on dry matter and yield of three tropical grain legumes. International Journal of Agriculture & Biology, 4, 405-407.
  18. Kumar, A., Sharma, K. D. & Kumar, D. (2008). Traits for screening and selection of cowpea genotypes for drought tolerance at early stages of breeding. Journal of Agriculture and Rural Development in the Tropics and Subtropics, 109 (2), 191-199.
  19. Kumar, J. H., Singh, T. S., Tonk, D. S. & Lal, R. (2002). Correlation and path coefficient analysis of yield and its components in summex moong (Vigna radiate L. wilczek). Crops Research, 24, 374-377.
  20. Majnoon Hoseini, N. (2008). Grain Legume Production. Jahad Daneshgahi Publication. University of Tehran. Fourth edition. 283 pp. (In Farsi).
  21. Mohammadi, A., Bihamta, M. R. & Dari, H. R. (2008). Determining of correlation coefficient and path analysis of some traits on chiti bean (Phaseolus vulgaris L.) under non-stress and drought stress conditions. Agricultural Research: Water, Soil and Plants in Agriculture, 8(2), 135-144. (In Farsi).
  22. Mohammadi, S. A. & Prasanna, B. M. (2003). Analysis of genetic diversity in crop plants-salient statistical tools and considerations. Crop Science, 43, 1235-1248 (In Farsi).
  23. Montgomery, D. G., Peck, E. A. & Vining, G. G. (2006). An introduction to liner regression analysis. John Willy and Sons, New York.
  24. Muuhouche, B., Ruget, F. & Delecolle, R. (1998). Effects of water stress applied at different phonological phases on yield components of dwarf bean. Agronomie, 18, 197-207.
  25. Nasri, R., Paknejad, F., Sadeghi shaae, M., Ghorbani, S. & Fatemi, Z. (2012). Correlation and path analysis of drought stress on yield and yield components of barley (Hordeum vulgare) in Karaj region. Journal of Agronomy and Plant Breeding, 8(4), 155-156. (In Farsi).
  26. Nienhuis, J. & Singh, S. P. (1986). Combining ability analysis and relationships among yield, yield component and architectural traits in dry bean. Crop Science, 26(1), 21-27.
  27. Ober, E. S. & Luterbacher, M. C. (2002). Genotypic variation for drought tolerance in Beta Vulgaris. Plant Pathology, 89, 917-924.
  28. Rosales-Serna, R. & Kohashi-Shibata, J. (2003). Biomass distribution, maturity acceleration and yield in drought - stressed common bean cultivars. Field Crop Research, 85, 203-211.
  29. Sabokdast, M. & Khyalparast, F. (2008). A Study of Relationship between Grain Yield and Yield Component in Common Bean Cultivars (Phaseolus vulgaris L.). Journal of Science and Technology of Agriculture and Natural Resources, Water and Soil Science, 42, 123-134.
  30. Singh, K. B., & Saxena, M. S. (2000). Breeding for stress tolerance in cool season food legumes. First Edition (Translation: A. R. Bagheri, A. Nezami & M. Soltani). Research Organizations, Education andAgricultural Extension. pp. 445.
  31. Soleymani, A., Moradi, M. & Naranjani, L. (2011). Effects of the irrigation cut-off time in different growth stages on grain and oil yield components of autumn’s canola cultivars in Isfahan region. Journal of Water and Soil, 25(3), 426-435. (In Farsi).
  32. Szilagyi, L. (2003). Influence of drought on seed yield components in common bean. Bulgarian Journal of Plant Physiology, Special Issue, 320-330.
  33. Weillenmann, M. E. & Luguez, J. (2000). Variation for biomass, economic yield and harvest index among Soybean cultivars of maturity Groups III and IV in Argentina. Soybean genetic Newsletter, 27. On line Journal (URL http// articles/sgn 2000).