<span name="style_bold">Adaptability and stability of 20 corn varieties in Panama. </span>The objective of this work was to determine the adaptability and stability of 20 corn varieties in Panama. From Sep tember 2007 to January 2008, uniform yield tests were evaluated in six locations with contrasting environments in Panama. The genetic material consisted of nine QPM synthetics and eleven with normal grains, all from CIMYT. The experimental design employed was complete randomized blocks with three replications. The experimental plots were two 5-m long rows with 0,75 m between rows. The combined analysis of variance showed statistically significant differences between the two groups (synthetic vs. normal) for yield and other economically and genetically important variables within groups. On the other hand, the interaction genotype X environment was significant for grain yield, indicating differential responses of the genotypes. The combined analysis of the mean yields showed that among the normal synthetics, SA-N6-07, SA-N8-07 and SA-N7- 07 exhibited outstanding yield with means higher than 4,0 t/ha, whereas within the QPM, SA-Q14-07 and SA-Q12-07 yielded 3,98 and 3,63 t/ha. The yield of a all these synthetics surpassed the normal grain control (Guararé-8128) and the QPM control (SA-Q5-06) which yielded 2.93 and 3.36 t/ha, respectively. The Biplot GGE-SREG model identified the synthetics SA-N6-07, SA-Q14-07 and SA-N10-07 with the highest stability; additionally, the first two were the best yielding varieties within each group.The objective of this work was to determine the adaptability and stability of 20 corn varieties in Panama. From Sep tember 2007 to January 2008, uniform yield tests were evaluated in six locations with contrasting environments in Panama. The genetic material consisted of nine QPM synthetics and eleven with normal grains, all from CIMYT. The experimental design employed was complete randomized blocks with three replications. The experimental plots were two 5-m long rows with 0,75 m between rows. The combined analysis of variance showed statistically significant differences between the two groups (synthetic vs. normal) for yield and other economically and genetically important variables within groups. On the other hand, the interaction genotype X environment was significant for grain yield, indicating differential responses of the genotypes. The combined analysis of the mean yields showed that among the normal synthetics, SA-N6-07, SA-N8-07 and SA-N7- 07 exhibited outstanding yield with means higher than 4,0 t/ha, whereas within the QPM, SA-Q14-07 and SA-Q12-07 yielded 3,98 and 3,63 t/ha. The yield of a all these synthetics surpassed the normal grain control (Guararé-8128) and the QPM control (SA-Q5-06) which yielded 2.93 and 3.36 t/ha, respectively. The Biplot GGE-SREG model identified the synthetics SA-N6-07, SA-Q14-07 and SA-N10-07 with the highest stability; additionally, the first two were the best yielding varieties within each group.

QPM; normal grain; yellow grain; Biplot GGE-SREG