LESS WATERLOGGING DAMAGE WITH LONG SEASON WHEATS

Fourteen wheat (Triticum aestivumL.) genotypes differing in the timing of apex development were grown in drained and undrained treatments on soil prone to waterlogging. A watertable was present in the undrained treatment but not in the drained treatment. The sensitive stage of apex development in the early maturing genotypes would have taken place under waterlogged conditions, but the watertable would have receded before apex development in the later maturing genotypes. There was a significant interaction between the drainage treatment and genotype in that the earlier maturing genotpyes yielded much less on the undrained treatment than did the later maturing genotypes which had similar yields on both treatments. Much of the yield reduction was associated with decreased grain number per ear.