GENOTYPE X ENVIRONMENT INTERACTIONS IN PROGENY FROM A BARLEY CROSS .2. VARIATION IN GRAIN-YIELD, YIELD COMPONENTS AND DRY-MATTER PRODUCTIONAMONG LINES WITH SIMILAR TIMES TO ANTHESIS

Barley lines from the cross cv. Triumph X cv. Grimmett with similar ti me to anthesis were evaluated for grain yield and several attributes r elating to growth and accumulation of grain yield in a range of enviro nments. Significant variation existed for mean grain yield across envi ronments, and for genotype X environment (GE) interaction. Principal c omponent analysis was used in an attempt to identify systematic differ ences in response for grain yield across environments. The first compo nent was positively correlated with grain yield in most environments, and most effectively accounted for this variation in the high-yielding environments. The second component was closely correlated with mean g rain yield across the lower-yielding rainfed environments, although it was negatively correlated with grain yield at one irrigated environme nt. Line scores on the first component were closely related to grain n umber across the high-yielding irrigated environments, and weakly corr elated with total dry matter and tiller number at anthesis in these en vironments. There was no correlation between line scores and TDM produ ction following anthesis. This suggested that the ability of lines to partition assimilate to grains, perhaps limited by grain number, is of importance in determining relative yield potential under favourable g rowing conditions. Deliberate evaluation of lines under such condition s may be appropriate in the early stages of selection of progeny. Line scores on the second component were positively corelated with mean gr ain number, TDM at anthesis, TDM production after anthesis and single- grain mass, across the rainfed environments. A negative correlation be tween line scores on the second component and numbers of late-developi ng tillers in the rainfed environments suggested that production of su ch tillers may be detrimental to high grain yield in these environment s. However, they may be useful in realising high grain yield in some i rrigated environments.