A field experiment was conducted at Sakha Agricultural Res. Station during
1998/1999 to' study the effect of ascorbic acid (C, = 1000, C2 = 3000 ppm as foliar
spraying), and soil moisture stress (0₁ = 50%, 02 = 70% and 03 = 90% depletion) on
. yield, yield components, and consumptive use indices of some wheat varieties (Vl =
Sakha 8: V2 = Sakha 61 and V3 = Sakha 69). Results could be summarized as follows:            *     Irrigation at 50% deple~ion produced greater values of grain and straw yields,
number of spikes/m , number of grains/spike, and 1000 grain weight than at 70%
and 90% depletion.            *    The variety of Sakha 69 was superieur when compared with Sakha 8, and Sakha
61 for grain and strawyields, number of splkes/rn", and number of grains/spike,
while Sakha '61 had the gre~test value of 1000-grain weight. * . The 1000 ppm ascorbic acid (as foliar spraying) resulted in greater values of grain
yjeld, No.· of splkes/m" and 1000 grain weight than those obtained by 3000 ppm,
-which has the greatest values of straw yield, and No. of grains/spike. .            *    The combined interaction (0 x V x C) showed significantly positive effect on yield
and agronomic traits of wheat crop. The values of grain and straw yields as well as 1000 grain-weight reached
maximum (3.487, 5.957 ton/fed. and 52.3 gm, respectively) by treatment (0₁ xV, . x e₁) whereas the treatment (02 'x V3 X C₁) and (0₂ x V2 X C~) recorded the
. greatest, values pf· 467 and 41.87· for : No. of spikes/rn'' and No. of grains/spike,
respectively. For consumptive use indices, it was cleared that water consumptive use (Cu) was
decreased with increasing soil moisture depletion and the greatest (41.12 cm)
was obtained at treatment 50% depletion compared with 25.48 cm for 90%                  depletion,                                   . Irrigation at 90% depletion resulted in significant value of W,U,E. (2.29 kg/m³) in
comparison to 50% (1.67 kg/m³) and 70% (1.97 kg/m\ The greatest values of moisture uptake from the surface layers were 38.25%,
32.83%, and 32.36% with water treatments 0₁,02, and 03, respectively.            *     For seasonal values of crop coefficient (Kc), generally Blaney-Criddle equation
gave over estimated values (1.108, 0.862, and 0.647 for 0₁,02 and 03) while
Penman and Radiation equations recorded the same values approximately and
then each of them can be suitable for using in the studied area.