Flag-leaf angle (FLAngle), flag-leaf area (FLarea) and flag-leaf area durat
ion (FLADuration) are important traits in determining yield in wheat (Triti
cum aestivum L). Genetic studies on these traits are very few. The objectiv
e of this study was to determine the gene action controlling those traits i
n four wheat crosses. Six generations were available for each cross: parent
s (P-1 and P-2), F-1, F-2 and backcrosses (BC(F1 x P1) and BC(F1 x P2)). Th
e joint scaling test described by Mather and Jinks was used to test goodnes
s of fit to eight genetic models. Models including additivity, dominance an
d interallelic interactions best fitted the data for the three traits and t
he four crosses. Additive effects were most prevalent for FLAngle. They wer
e also significant for FLArea and FLADuration. Dominance and epistatic gene
action were also found, but the degree and direction was both trait- and g
enotype-specific. Heritabilities values were intermediate. Genetic progress
, although slow, can be expected when selecting for these traits; however,
selection would be most effective if delayed to later generations because o
f dominance and epistatic effects.