A field trail was conducted at Jeleen Research Station, Dara,a governorate,
Syria, during two consecutive growing seasons (2010/ 2011-2011/ 2012), in
order to evaluate the role of some cultural practices in improving nitrogen use
efficiency and gr
ains quality characteristics of four wheat varieties (Acsad1105,
Acsad1229, Acsad885 and Acsad901). The experiment was laid according to
randomized complete block design-split, with three replicates. Leaf area index,
grain starch content and grain yield were significantly higher during the first
growing season, in the wheat variety (Acsad901), for the first planting date, and
nitrogen rate (200 Kg N. ha1-), when nitrogen fertilizer was added in two splits
(1.25, 68.60 %, 1051 g. m-2).
The performance of some barley genotypes was evaluated under rain-fed
conditions in Dara'a (Izra'a) during two successive growing seasons (2009-2010/
2010-2011) in order to determine the most relevant physiological traits, which
are genetically as
sociated with drought tolerance and grain yield. The trial was
laid out according to the factorial complete randomized block design, with
three replicates. The leaf area index (LAI) was significantly lower in the wild
relatives compared with the varieties and land races. Relative water content
was significantly higher during the second growing season (87.19%) compared
with the first one (71.57%). Solute leakage was significantly lower during the
second growing season (69.50%) compared with the first growing season
(76.49%). It was noticed that the genotypes which have achieved significantly
higher grain yields, could also maintain significantly higher relative water
content in the leaves, (Acsad176, Acsad1182 and Acsad60), and were superior in
maintaining membrane integrity, and leaf area index, indicating the
importance of such traits in improving drought tolerance and maintaining
production capacity.
Several laboratory experiments were conducted to evaluate the response of
ten ACSAD durum and bread wheat landraces to salinity stress tolerance at
seedling stage. The salinity induction response technique was applied to assess
the genetic variabi
lity, and the effect of induction nature in improving the
tolerance to lethal levels of some abiotic stresses (drought and salinity). The
applied screening tool was rapid and efficient in assessing the genetic
variability for the response of studied durum and bread wheat landraces to
salinity stress tolerance.
A laboratory experiment was conducted during 2002-003. The purpose was
to develop an effective and rapid screening tool to assess the genetic variability
for the response of some local barley varieties to polyethylene glycol- induced
osmotic stres
s at early growth stage. Also this will help to evaluate the relevance
of pre-exposure of barley seedlings to sub-lethal (induction) levels of osmotic
stress. This might enhance the capacity of seedlings to tolerate the lethal levels
of stress.
This investigation is a mimesis to what usually happens in nature, where the
plants are normally exposed to sublethal environmental stresses before their
exposure to the lethal level of stresses.
The gradual increase of environmental stress, gives
plants a suffficient time
to prepare their defensive means to withstand the lethal level of stress. In order
to develope a suitable screening technique, it was essential to determine the
induction as well as the lethal levels of stress, as important components of such
proposed tool.
This technique was applied to screen some tomato genotypes, and assess the
genetic variability among them, in order to evaluate their salinity stress
response , and selecting the highly salt tolerant types.
Determination of the optimum induction and lethal levels of stress are
considered the most important prerequisites for the proposed screening
technique. This research was conducted at the Faculty of Agriculture at
Damascus University in the year ٢
٠٠٠. The main objective of this investigation
was to screen sorghum lines for heat stress tolerance and determine the
effectiveness of the proposed technique in screening for this environmental
stress at the seedling stage.
A field study was carried out at the Al-Maraiah Research Station of the Agricultural Scientific Research Center in Deir ez-Zor, the General Authority for Scientific Agricultural Research, during the 2009, 2010, and 2011 agricultural seasons, to evaluate the response of some cultivars of maize to withstand water stress during the flowering and grain filling stages.
