Stability of Soybean Genotypes in Central Plain Thailand

Abstract

Genotype x environment interactions and stability estimates for yield and yield components of soybean genotypes were carried out at Khao Hin Son Research Station, Chachoengsao Province during July 1996 and December 1996. The experiment consisted of ten soybean genotypes (IAC–2, VX4.16.12, CPAC 150–76, CPAC 359–76, CPAC 639–76, TGX1447–3D, Santa Maria, KUSL 20004, CM 60 and SJ 4) in twelve environments (3 plant densities, 200,000 300,000 and 400,000 pl/ha and 4 planting dates, July 8, 1996, August 30, 1996, October 22, 1996 and December 14, 1996). Despite variation between environments, most soybean genotypes did not give significant response. Significant mean squares of genotypes for yield and yield components indicated the existence of genetic variability in these characters. Although changes in yield and yield components of some genotypes were linear functions of the invironments, genotypes appeared to be the most important factor contributing to the variation in yield and
yield components. Yield improvement through selection is, therefore, possible across these environments. The results of stability estimates suggested that the top four genotypes with good adaptability were VX4.16.12 (1,372 kg/ha), Santa Maria (1,381 kg/ha), KUSL 20004 (1,732 kg/ha) and CM 60(1,468 kg/ha).