WHEAT CULTIVARS: RESPONSE TO IRRIGATION AND SOWING DATES

This study was carried out in an Alfisol-Oxisol transition sandy-clay texture, using six wheat cultivars (Triticum aestivum, L.): two tall and tolerant to soil aluminium toxicity (BH-1146, and IAC-18), and four semi-dwarf cultivars - Anahuac, IAC-162, IAC-24, and IAC-60 - of which only the first two are sensitive to soil aluminium toxicity. Two minimum soil water potentials (ys) levels were used: 1. watered, when Ys reached about -0.05 MPa; 2. dry, when the water potential reached around -1.5 MPa. Two sowing dates, 05/22/92 and 06/11/92, were used. The results showed that Anahuac and IAC-60 are the most indicated cultivars for the studied region; when irrigated all cultivars presented similar yield level under no irrigation conditions; the irrigation was not sufficient to avoid yield differences between the two growing seasons; differences in rainfall were important for the crop in the dry treatment for both seasons