Abstract:
Drought and associated high temperatures are
the major environmental stresses limiting wheat
productivity in Mediterranean region. To evaluate
the physiological and yield responses of durum
wheat varieties under high temperature and drought
stress in Mediterranean region, 15 durum wheat cul tivars were grown in two consecutive years (2007-
08 and 2008-09). The varieties were grown under
two temperature regimes viz. normal temperature
(normal sowing time) and high temperature (late
sowing time), and/with two water regimes viz. rain fed (RF) and supplement irrigation (SI) conditions.
Our results indicated that at rain-fed environment
(water stress) caused a significant reduction in phys iological parameters and grain yield. Water stress re duced 30.0 and 13.8% grain yield in 2007-08 and
2008-09, respectively. Warm environment (heat
stress) caused significant reductions in physiological
parameters and grain yield of 54 and 32% in 2007-
08 and 2008-09, respectively. Hence, delayed sow ing associated with high temperature resulted in an
overall decrease in grain yield. Significant differ ences in grain yield was found among the varieties.
Based on the growth traits and economic-yield, the
cool irrigated environment is most suitable followed
by the environment in cool rain-fed. However, the
variety %DOFDOÕ-2000 and Fuatbey-2000 achieved the
highest yield under cool well-watered conditions and
hence best for grown under well-watered cropping
systems. Grain yield was strongly correlated with
SPAD value in cool environment (RF) while, nega tive correlation in warm conditions (RF). On the
other hand, grain yield was strongly correlated with
specific leaf weight (SLW) value in cool environ ment (RF). A negative correlation between grain
yield and flag leaf nitrogen content (FLNC) was ob served under warm conditions (RF). A positive and
significant correlation between SLW and FLNC was
recorded under warm conditions (RF). The ash con tent (AC) has a positive correlation with FM in cool
environment (SI). A positive and significant correla tion between FLNC and SPAD under cool (SI) and
warm (Rf) conditions. The chlorophyll fluorescence
contributes significantly to yield stability under
stressed environments. Positive correlations of chlo rophyll with grain yield make it possible to evaluate
genotypes with high yield stability and conse quently, can be used as a selection criterion to iden tify the environment stress tolerance of wheat geno W\SHV %DOFDOÕ-2000 and Sölen-2002 cultivars are po tentially good candidates for producing good yield in
the hot and dry climates in Mediterranean conditions.
