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

Barley lines from the cross cv. Triumph X cv. Grimmett with similar time to anthesis were evaluated for grain yield and several attributes relating to growth and accumulation of grain yield in a range of environments. Significant variation existed for mean grain yield across environments, and for genotype X environment (GE) interaction. Principal component analysis was used in an attempt to identify systematic differences in response for grain yield across environments. The first component 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 grain yield across the lower-yielding rainfed environments, although it was negatively correlated with grain yield at one irrigated environment. Line scores on the first component were closely related to grain number across the high-yielding irrigated environments, and weakly correlated with total dry matter and tiller number at anthesis in these environments. There was no correlation between line scores and TDM production 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 growing conditions. Deliberate evaluation of lines under such conditions may be appropriate in the early stages of selection of progeny. Line scores on the second component were positively corelated with mean grain number, TDM at anthesis, TDM production after anthesis and single-grain mass, across the rainfed environments. A negative correlation between line scores on the second component and numbers of late-developing tillers in the rainfed environments suggested that production of such tillers may be detrimental to high grain yield in these environments. However, they may be useful in realising high grain yield in some irrigated environments.