Effect of Sowing Date and Weed Control on Grain Yield and its Components in Some Wheat Cultivars

The influence of sowing dates (Oct. 21, Nov. 10, Nov. 30 and Dec. 21), weed control treatments using Brominal, Tribunil herbicides as compared to hand weeding and unweeded treatments on the yield performance of newly released spring wheat varieties ( Sakha 8, Sakha 61 and Giza 157 was studied during 1980/81, 1981/82 and 1982/83 seasons. According to the combined analysis the results could be summarized as follows:

• 1. 

  Sowing date had significant effect on grain yield and some other characters such as plant height, days to heading and maturity, weight of grains per spike and 1000-grain weight. Highest grain yield was obtained when wheat was sown during Nov. Dry weight of weeds was not significantly affected by sowing date.
• 2. 

  Differences between cultivars reached to the significant level in plant height, spike length, number of grains per spike and 1000-grain weight.
• 3. 

  Weed control treatments had significant effect on most studied traits. Grain yield was nearly the same when Tribunil (3.5 kg/ha), Brominal (2.4 1/ha) or hand weeding was used. Grain yield of unweed treatment decreased by 10.9%, 10.9% and 9.8% compared to the former treatments, respectively.
• 4. 

  Data showed that Tribunil was more effective on both grassy and broad leaved weeds, however, Brominal was effective only on broad leaved.