Genetic Variation for Yield and Yield Components in Sole Soybean and Soybean/Celosia Inter-Crop in Makurdi (Southern Guinea Savanna Ecology), Nigeria

Aims: To determine genetic variation in soybean grown alone and in soybean/celosia intercrop system, and to provide information on the appropriate system to concentrate in a breeding programme.

Study Design: The experimental design was a randomized complete block design (RCBD) with three replications for each of the cropping systems in each of the years.

Place and Duration of Study: Field experiments were carried out at the Teaching and Research Farm of the Federal University of Agriculture, Makurdi, Nigeria, during the cropping seasons of 2006 and 2008.

Methodology: Twenty - five to thirty - nine improved varieties of soybean were evaluated in sole and soybean/celosia intercrop for each of the years. Data were taken on days to flowering, plant height, number of pods/plant, 100 – seed weight and grain yield for soybean in both cropping systems. Data were analysed using analysis of variance and components of genetic variation.

Results: Highly significant difference in varieties was observed for all the traits studied in the sole and intercrop soybean for each of the years with significantly higher grain yield in 2008 compared to 2006 in both the sole and intercrop soybean due to planting at the recommended planting date for soybean in 2008.Genetic variance was higher than error variance for all the traits in the sole soybean except 100 – seed weight in 2006. Genetic variance in the intercrop soybean was lower than the error variance for three out of the five traits studied leading to proportionally lower heritability estimate and genetic advance for almost all the traits in intercrop soybean compared to sole soybean system.

Conclusion: The evaluated varieties of soybean are genetically diverse. A faster progress in selection will be achieved in the sole soybean and should be adopted in the selection of soybean genotypes for soybean/celosia intercrop system.