An experiment was carried out at the Animal Science Experimental Station of Sertãozinho, São Paulo, Brazil. The experimental design was a randomized block design, with three replications. Plots were constituted of 5 rows, with 5m long, separated by 0.2m. Thirty-five alfalfa cultivars were evaluated for dry matter yield in 29 yielding dates, from October, 1996 to March, 1999. Adaptability and stability study was stimated with “Eberhart & Russell” and “Lin & Binns” methods. Significant cultivar x yielding dates interaction was verified, indicating that the relative behavior of the cultivars was not the same in the different yielding dates. Among the 35 evaluated cultivars, 14 presented wide adaptability (<FONT FACE=Symbol>b1i</FONT> = 1) and good predicability ( <FONT FACE=Symbol>s²di</FONT> = 0), according to the “Eberhart & Russell” method. Among 10 cultivars that had high adaptability and predicability (smallest values of Pi), estimated by “Lin & Binns” method, seven also had high adaptability and good predicability, estimated by “Eberhart & Russell” method. The cultivars SW 8210, Victoria SP, MH 15, 5888, Araucana, BR 1 and BR 3 had the high test adaptability and predicability, estimations obtained in both employed methods.
cultivar x environment interaction; yielding dates; Medicago sativa L
