Adaptability, stability and resistance to the stem canker in soybean.

Abstract

The adaptability and phenotypic stability of 20 soybean inbred lines were evaluated regarding to plant height, first pod insertion and yield within six experiments carried out in Jaboticabal, Ilha Solteira and Ituverava, state of São Paulo, Brazil, during two cropping seasons (998-999, 999-2000). The experimental design was the randomized blocks with three replications, being each plot formed by two 5.0 m long rows and with 0.50 m between rows. Adaptability and stability parameters were estimated. The genotypes JB95-30025, JB95-3002 and JB95-5002 exhibited general adaptation to all the environments. Most of the genotypes showed stability for the evaluated traits. The genotype JB95-50027 was stable only for grain yield. The resistance of genotypes to stem canker was also evaluated. Plants in stage V (start of vegetative period) were inoculated by the “toothpick” method and evaluated thirty days after inoculation. The experimental design adopted was the randomized blocks with five replications with forty plants of each genotype. The genotypes JB50027 and JB94-020 were found to be resistant and their utilization as parentals in breeding programs viewing the development of genotypes resistant to stem canker and with other important agronomical characteristics is suggested. Their inclusion in national variety trials is also suggested.Additional keywords: Glycine max; phenotypic stability; disease resistance.