An experiment with the objective to study the behaviour of the wheat cultivar IAC-24 under three moisture levels (0.01-0.03; 0.03-0.50 and 0.50-1.50 MPa), using pots with soil (Latossolo Roxo eutrófico) was carried out under green-house conditions at Instituto Agronômico, Campinas, State of São Paulo, Brazil, during 1985. It was measured spike lenght, number of spikes per pot and per plant, total number of spikelets per spike, number of grains per spikelet and per spike and grain yield as affected by the three soil moisture levels. All characters increased significantly as the water availability in the soil increased from 0.50-1.50 to 0.01-0.03 MPa. In the experiment the critical moisture level was 0.50 to 0.03 MPa; so as the water potential decreased below this level there was a decrease in grain yield and in the agronomic characteristics. Changing the moisture level of the soil from 0.03-0.50 to 0.01-0.03 MPa, there was a significant increase in the grain yield. The moisture level showed to be very important in studies where grain yield and economic value of the crop are involved.
wheat; soil water potential; soil moisture level; yield components