557irrigation in a semiarid area of Algeria. The experiment was undertaken at the
Bessami Djillali pilot farm located in Khemiss Meliana in northwestern Algeria.
Sowing occurred on December 11, 2012, at a density of 300 seeds m−^2 and row
spacing of 20 cm. Durum and bread wheat cultivars (durum wheat—Bousselam,
Simeto, Megress, GTA dur, Amar 6; bread wheat—ARZ, HR 1220, ANZA,
Maaouna, Ain Abid) were cultivated under full supplemental irrigation (100 % SI),
deficit supplemental irrigation (50 % SI) and rainfed regimes. The experimental
design was a strip plot with water regime as the main plot and variety as the split
plot with three replications of each treatment. Annual rainfall received during the
season was 399 mm (annual average is 442 mm).
Supplemental irrigation of 60 mm (100 % SI) or 30 mm (50 % SI) was applied
between booting and anthesis when the soil water deficit was 50 % below soil avail-
able water content (AWC). The effects of supplemental irrigation (p < 0.001), spe-
cies (p = 0.004) and their interaction (p = 0.010) on grain yield were significant;
while genotype (p = 0.142) and supplemental irrigation x water regime x genotype
interaction (p = 0.476) were not significant. The 50 % SI application to bread wheat
generated significant increases in grain, biomass and straw yields, as well as kernel
number and thousand kernel weight, relative to the rainfed control. The interaction
of water regime x genotype was not significant. The average grain yield of all treat-
ments was 2.7 t ha−^1 (3.01 t ha−^1 for bread wheat and 2.46 t ha−^1 for durum wheat).
The 100 % SI treatment produced 3.4 t ha−^1 of grain yield, the 50 % SI treatment
produced 3.3 t ha−^1 and rainfed 1.5 t ha−^1. On average, the irrigation treatments
improved grain yields by 36.8 % compared with the rainfed regime (2.2 t ha−^1 ).
Additional water supply beyond 50 % SI did not generate any significant gain in
yields (Table 5 ).
Table 4 Probability of significance for yield, yield components and agronomic characters
measured in three wheat genotypes grown under four irrigation treatments in the northern part of
Jordan during the 2013–2014 and 2014–2015 growing seasons
Trait Irrigation Variety Irrigation*variety CV
DH ns ns 1.7
DM ns ns 1.19
PH ns 3.6
TPP ns ns ns 25.64
SPM * 7.78
BYD * ns 7.73
GYD ns 9.93
KPS ns ns 10.25
TSW * ns 4.95
NS not significant, DH days to heading, DM days to maturity, PH plant height, PPM number of
plant per square meter, TPP number of tiller per plant, SPM number of spike per square meter,
BYD biological yield, GYD grain yield, STY straw yield, KPS number of kernels per spike, TSW
thousand seed weight, HI harvest index
, ** are significant at P ≤ 0.05 and P ≤ 0.01, respectively
Supplemental Irrigation: A Promising Climate-Resilience Practice for Sustainable...