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Severe water deficit is common during crop establishment in many areas of the semi-arid tropics. The influence of non-lethal water deficit imposed for 19 days after sowing was investigated in maize using a water gradient applied with an irrigation system mounted under a rainshelter. Water deficit had little effect on timing of emergence but delayed tassel initiation and silking by up to 4 days. Water deficit reduced the rate of leaf appearance and area of leaves 5 to 9, but did not greatly influence the number of leaves or total leaf area per plant. Marked differences in height and biomass, that were apparent on day 21, were not evident on day 51 and there was no influence of water deficit on mean+/-s.e. grain yield (77+/-6.3 g plant-1) or grain numbers (391+/-32 grains plant-1).

The threshold of available soil water below which water deficit affects phenology and leaf appearance appeared to be lower than for the effects on leaf expansion and accumulation of biomass above ground.

We conclude that non-lethal water deficit during early vegetative growth of maize results in marked reduction in height and biomass and delays crop phenology but may not be associated with lower yield potential.