Abstract:
Water stress, which limits the
distribution and productivity of durum
wheat (Triticum durum Desf.) in the
Mediterranean region, is also considered to
be a major factor reducing yield in semiarid
regions. Improving drought resistance is
thus an important objective in plant
breeding programs for rainfed agriculture.
The current study was carried out to identify
drought-tolerant durum wheat lines among
10 lines and one variety (Douma1, the
control) in the first and second settlement
zones in the Southern part of Syria and to
recognize the most important physiological
parameters associated with drought
tolerance. Membrane stability index,
chlorophyll (chl) content, relative water
content and chl fluorescence were recorded
at the vegetative and anthesis stages, as
were yield and yield components. Data
recorded at vegetative and anthesis stages in
both zones showed that there were
significant differences between all lines
growing in the first and second settlement
zones and that all characters in the second
zone were significantly lower than those in
the first zone. Line 1 was superior to
Douma1 in terms of membrane stability
index, relative water content, chl content
and chl florescence, also showing better
yield and higher total plant biomass, tiller
number/m2, 1000 grain weight and grain
number/ear than the control. The ability of
wheat cultivars to perform reasonably well in variable rainfall and water-stressed
environments is an important trait since it
allows for stable production under drought
stress. Moreover, prior to genetic
manipulation, it is important to characterize
the physiological parameters of known
drought-tolerant or drought-sensitive wheat
cultivars with the objective of better
understanding their physiological responses
under drought.
