YIELD STABILITY OF OAT GRAIN - EFFECT OF THE USE OF FUNGICIDES

Twenty oat (Avena sativa L.) genotypes were evaluated for grain yield stability and the effect of fungicide application on the genotype x en vironment (GxE) interaction in four locations in southern Brazil durin g 1986, 1987 and 1988. Eberhart & Russell's (1966) parameters (X, b an d Sd) were adopted and analyses were performed according to three mode ls: with fungicide application, without fungicide application, and, co mplete model. Results indicated a strong GxE interaction, although no genotype showed stable grain yield performance, as shown by the high r egression deviations observed. Fungicide application caused an increas e in mean grain yield performance, but did not affect the GxE interact ion. UPF 7 and UFRGS 7 appear to be good genotypes for southern Brazil because they are productive and insensitive to environmental changes; on the other hand, UPF 6 and UFRGS 10 could be more useful for farmer s, since they respond positively to the environmental improvements.