EFFECT OF SOWING DATE AND IRRIGATION INTERVALS ON YIELD AND ITS COMPONENTS OF SOME WHEAT CULTIVARS.

The Field experiments were conducted out during the twosuccessive winter seasons of 2012/2013 and 2013/2014 at theExperimental Farm (Demo) of the Faculty of Agriculture, at FayoumUniversity, Egypt .The aim of these experiments was to evaluate yieldand yield components of some wheat cultivars under different SowingDates and different irrigation intervals . The experiment was laid outin split - split plot design with four replicates and comprised of threedates of Sowing, namely 1st November, 15th November and 30thNovember in main plots and three irrigation intervals, namely, I1Irrigation every 21 days, I2 Irrigation every 28 days, I3 Irrigation every35 days, in sub- plots and three wheat cultivars namely, Sakha 93,Sakha 94, and Sids 12 in sub-sub-plots. The results of wheat cultivars,irrigation intervals and different sowing dates mostly showedsignificant differences (P < 0.05) for yield and yield components. Thecultivar Sids 12 scored the first rank in all characters. Irrigationintervals showed significant differences on all characters exceptnumber of spikelets/spike and irrigation every 28 days recorded thehighest values in most characters followed by every 35days. Thesowing dates shown significant effect on all traits except harvest indexand the highest values were obtained when cultivars sown in 15thNovember in most characters. The results indicated that crop plantedon November 15, produced higher grains yield as compared to late andearly planting. This indicated that late sowing shortest the developmentphases of wheat and adversely affected the grains development andthus the grain yield. On the other hand, The interactions effect betweensowing date and irrigation intervals, sowing date and wheat cultivar,irrigation intervals and wheat cultivar and sowing date x irrigationintervals x wheat variety remained significant on all traits except theinteraction between irrigation intervals and wheat variety on spikelength, weight of grain/spike, seed index and harvest index. Generally,Sids12 under sowing on 30th November and irrigation every 28daysfollowed by the same variety when sowing on 15th November andirrigation every 35days surpassed on the other tested treatments ingrain yield/fed. (2.97 and 2.93 t/fed.) respectively.