ACCUMULATION OF DRY-MATTER AND NITROGEN IN THE DEVELOPING SEEDS OF HIGH-PROTEIN MUTANT LINES OF TRITICUM-AESTIVUM (L) PRODUCED BY THE IAEA

Accumulation patterns of dry matter and nitrogen in the developing seeds of nine mutant lines produced by the IAEA and their mother line Mex22A T.aestivum (L.) were studied. The experiments were grown for 2 years under rainfed conditions. Significant differences were found among the lines in all studied characters except for final seed weight. High rates of accumulation of dry matter and nitrogen were associated with a short period of accumulation. However, the two lines with the highest N rate accumulation were also very late in flowering and therefore had the lowest yield per plant, presumably due to higher sterility resulting from higher temperatures at anthesis. All other mutant lines had a higher seed nitrogen percentage than the mother line without any reduction in seed weight. This was primarly due to higher rates of N accumulation. Six of the mutant lines had comparable yield/ plant and were higher than the mother line in N yield/ plant. It was concluded that early flowering genotypes with higher N rates of accumulation should be sought to avoid the high sterility that occurs with high temperatures at anthesis.