An experiment was conducted in Kharabo station which belongs to the
faculty of agriculture, Damascus university during the growing season 2009 !
2010, to evaluate the response of seventeen sorghum genotypes under water
stress conditions during the flowering stage according to the randomized
complete block design (RCBD), with three replicates.
Ssilverleaf nightshade (Solanum elaeagnifolium Cav.) is a serious weed to
cotton and other field summer crops due to the alkaloids present in the plant
and have allelopathic potential on the germination of other plants. Sorghum
(Sorghum bicolor) h
ave been investigated as a allelopathic crop having strong
competition potential in the field containing many numerous water solution
allelochemicals and can be used to control weeds in field crops. A field
competition study between sorghum and silverleaf nightshade plants was
conducted to determine how long every plant can resist against the other.
A hydroponic culture experiment was conducted under the green house
conditions, at the general commission of scientific agricultural research, and
the faculty of agriculture, Damascus university, during the year 2002-003.
The objectives of this in
vestigation concentrated on the influence of four
salinity levels (0-50-100-150 mM NaCl) on some physiological parameters of
eight sorghum genotypes. The experiment was designed in a RCB design with
three replications.
Heritability and genetic advance of some grain yield components and some
morpho-physiological traits in 36 sorghum hybrids [Sorghum bicolor L.
Moench] produced by top-cross using cytoplasmic male sterility were
estimated.
Narrow-sense heritabilit
y for plant height and head length were relatively
high in Damascus location (65% and 56%) respectively, but the narrow-sense
heritability of all characters in Raqqa location were low, the range was from
3% for threshing percentage to 34% for plant height, and from 22% for seed
weight/head to 60% for plant height in the combined analysis.
Genetic advance estimates were relatively low for all characters, the range
was from 0% for 100 seed weight to 28.3% for plant height (Damascus
location), and from 0.02% for seed numbers/head to 15.2% for plant height
(Raqqa location), and from 5.8% for the number of days to flowering to 26.5%
for plant height (combined analysis).
Some characters such as plant height and head length showed relatively
high values of heritability, but exhibited low values of genetic advance.
Therefore other characters had low heritability coupled with low values of
genetic advance indicated predominance of non-additive gene action. This
result implies the need for several generations of selection to improve grain
yield components and other traits.
Different experiments were conducted under laboratory conditions, at the
Faculty of Agriculture – Damascus University, in order to develop a suitable
and efficient screening tool, which can be applied to assess the genetic
variability among 20 sor
ghum genotypes (Izraa series) for high salt stress
tolerance.
We were able to develop a screening technique involves pre- exposing
sorghum seedlings to a sub – lethal level of salinity stress (induction stress) (150
mM NaCl) for 16 hrs which can induce the genotypes to prepare defensive
means, which may differ according to the genetic potentiality of each genotype.
These protective responses may help the genotype to endure the lethal level of
salinity stress (400 mM NaCl) for 48 hrs. At a later stage, the seedlings were
transferred to distilled water for 72 hrs and the rate of recovery growth was
taken as a criterion to select the highly salt tolerant genotypes by using Zdistribution
analysis.
Results revealed that genotypes such as: Izraa 10, Izraa 15, and Izraa 18
could be classified as salt tolerant genotypes which showed higher recovery
growth and the least growth reduction over the control. Whereas a genotype
such as Izraa 22 was grouped as salt sensitive one where the percent growth
reduction over the control was greater, indicating that this genotype has low
recovery growth ability.
Our results suggest that the proposed screening technique is rapid, effective,
and match the natural screening.
This study was conducted at the General Commission Of Scientific
Agricultural Research (GCSAR) for tow consecutive years, 2000-2001, to
estimate the heterosis of some sorghum hybrids utilizing cytoplasmic male
sterility technique, and to determine
the behavior of the parents used in
hybridization concerning their relation to the cytoplasmic male sterility.
Hybrids were planted in a randomized complete block design, including 43
hybrids in tow replications.
The results showed variation among parents characters, because they were
selected from different environments and also differ in genetic components.
positive heterosis was recorded form crosses involved foreign parents with
local ones, or foreign hybridized with foreign. positive heterotic values for
earliness and productivity were obtained .
The genetic constitution of the male parent was assessed as R-line (restoring
of the A-line), and B-line (maintainer of the A-line).
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.
