Full Length Research Paper

Evaluation of soybean [Glycine max(L) Merrill] genotypes for adaptability to a southern Guinea savanna environment with and without P fertilizer application in north central Nigeria.

M. O. Aduloju¹, J. Mahamood² and Y. A. Abayomi¹*

¹Dapartment of Agronomy, University of Ilorin, P.M. B. 1515, Ilorin. Nigeria

²Lower Niger River Basin Development Authority, P. M. B. 1529, Ilorin, Nigeria.

*Corresponding author: E-mail: yabayomi2007@yahoo.com , abiyomi@unilorin.edu.ng . Tel.: +2348060553813

Accepted 11 June, 2009

   Abstract

Cultivar evaluation is essential to ascertain the superiority of the newly developed genotypes over the established cultivars in terms of yield and adaptation to an ecology. Field experiments were conducted to evaluate some of the recently developed soybean genotypes with and without P fertilizer application for adaptability to southern Guinea savanna ecology of Nigeria. The study was carried out at the experimental field of the Teaching and Research Farm, University of Ilorin, Nigeria, during the 2003 and 2004 cropping seasons. Application of 30 kg P ha^-1 resulted in significantly higher growth and grain yield parameters compared to no P application. Grain yield was consistently significantly higher for TGX 1448-2E than for other genotypes including the established cultivar, TGX 923-2E over the two cropping seasons. Significant year x genotype effect indicated that grain yields were significantly different between the two cropping seasons for TGX 1830-20E, TGX 1740-2F and TGX 1871-12E in 2004, while there was no significant variation for grain yield for TGX 1448-2E, TGX 1844-18E and TGX 1869-31E for the two years. This suggests stable grain yields in the latter genotypes and hence good adaptability, while the former ones showed unstable productivity under adverse soil moisture condition resulting from lower rainfall in 2003, and thus were deemed unsuitable for the southern Guinea savanna ecology which is highly prone to drought conditions. Simple linear regression analysis revealed that number of pods per plant was the most important factor influencing grain yield in this study. In conclusion, TGX 1448-2E was the genotype best adapted genotype to the southern Guinea savanna ecology and thus it can successfully replace TGX 923-2E the existing cultivar. Nevertheless, TGX 1844-18E and TGX 1869-31E are promising as drought tolerant genotypes.

Key words: Adaptability, southern Guinea savanna ecology, new soybean genotype, P fertilizer application.