Effects of sowing date and irrigation interval on growth and yield of wheat (Triticum Aestivum L.)‎ and its thermal time requirements under new halfa environment

الملخص EN

Effects of sowing dates and irrigation regimes on growth and yield of wheat were investigated at New Halfa Scheme during the seasons 1988 / 89 and 1989/90.

Climatic data were obtained from New Halfa meteorological substat-ation.

Evapotranspiration (ET), crop factor (CF), tiller number and dry matter production were determined.

Thermal time requirements for tillering, dry matter production and phenological growth stages were calculated.

The results showed that late November sowing dates (November 20th and 28th) generally produced higher values for ET, CF, number of tillers, dry matter production, number of heads/m2, number of grains / head, 1000-seed weight and final grain yield than those of late sowings (December, 15th and 25th).

However, no significant differences were noted regarding these parameters due to irrigation regimes.

The results also show that wheat required about 1546 degree-days (oCd) from planting to maturity.

It is concluded that late December sowings may subject wheat to heat stress, and hence poor grain yields