ملخص رسالة الماجستير للسيد/إبراهيم نجاح عبد الظاهر

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This investigation was
carried out at two locations (Assiut and Sohag) during 2003 and 2004 seasons.
The main objective of this study was to identify the high yielding crosses
tolerant to drought stress.


Eleven parents (five
female and six male lines) were selected randomally to this study. The six restorer lines were
top crossed at Shandaweel Agric. Res. Station, Sohag in 2003 season with five
cytoplasmic male sterile lines to develop thirty crosses. These crosses and
their parents and one check (Shandaweel-6) were evaluated at the two locations
in season 2004 under two levels of irrigation 100% and 40% ET.


A split-plot in RCBD
design with three replications was used where the irrigation levels (100%
optimum and 40% from the optimum) located in the main-plot and the genotypes
located in the sub-plot. Line x tester analysis were used to compute the
genetic parameters.


The results of the
present investigation could be summarized and presented in the following
topics:


1- Analysis of variance:


The analysis of variance for female lines, male lines and their crosses
under each level of irrigation at each location manifested that significant
differences were found between female lines, male lines and crosses under each
level of irrigation at each location for all the studied traits, except between
female lines for panicle length and 1000-grain weight under 100% level of
irrigation at Sohag location.



The combined analysis of variance for female lines, male
lines and their crosses under each level of irrigation over two locations
showed significant differences were found between two locations for all the
studied traits, except panicle length for the female lines and crosses and
panicle width for the male lines under 100% level of irrigation over two
locations and 1000-grain weight for the crosses under each level of irrigation
over two locations. Significant differences between female lines, male lines and crosses were
found for all the












studied traits under
each level of irrigation over two locations except number of green leaves for
male lines under 100% level of irrigation over two locations.


The analysis of variance for both Assiut and Sohag locations showed that
significant differences between irrigation levels at each location were found
for all the studied traits. Also, significant differences between female lines,
male lines and crosses were found at each location. The female lines, male
lines, females x males and crosses x
irrigations interactions were significant for all the studied traits at Assiut
location, except number of green leaves for females x irrigations interaction
and number of days to 50% flowering for males x irrigations interaction and
number of days to 50% flowering and panicle length for females x males x irrigations
interaction while, at Sohag location the traits which exhibited significant
differences for this interactions were plant height and grain yield/plant for
female lines, females x males and crosses x irrigations interactions and days
to 50% flowering and grain yield/plant for male lines x irrigations
interaction.


Mean performance of
female lines, male lines and crosses were decreased under water stress
condition (40% level of irrigation) for all the studied traits, except days to
50% flowering which increased. Mean performance of female lines, male lines and
crosses at Sohag location were better than those at Assiut location for all the
studied traits, except panicle length for the female lines and crosses and
panicle width for the male lines under 100% level of irrigation over two
locations and 1000-grain weight for the crosses under each level of irrigation
over two locations where, non-significant differences were found between two
locations under mentioned level of irrigation.



The crosses ATX-89002 x RTX-2794, ATX-89002 x
Adv.3/2002, ICSA-155 x RTX-2794,
ICSA-155 x Adv.3/2002, ICSA-155 x Adv.4/2002 ICSA-47 x RTX-2794, ICSA-47 x
Adv.6/2002, ICSA-70 x RTX-2794 and
ICSA-70 x Adv.4/2002 were significantly earlier than the check hybrid
(Shandaweel-6) under two levels of
irrigation at the two locations.The crosses ICSA-155 x RTX-2794, ICSA-155 x
RTX-2817, ICSA-70 x RTX-2794 and ICSA-70 x RTX-2817












were significantly shorter than the
check hybrid under two levels of irrigation at the two locations. The crosses
ICSA-35 x RTX-2794, ICSA-155 x RTX-2794, ICSA-155 x Adv.3/2002, ICSA-155 x
Adv.4/2002, ICSA-47 x RTX-2794, ICSA-70 x RTX-2794 and ICSA-70 x Adv.4/2002
under 100% level of irrigation over two locations and 40% level of irrigation
at Assiut location and the cross ICSA-35 x Adv.4/2002 under 100% level of
irrigation over two locations and 40% level of irrigation at Sohag location
were significantly taller panicle length than the check hybrid. Only the cross
ATX-89002 x Adv.4/2002 had wider panicle width than the check hybrid under two
levels of irrigation at two locations. The crosses ATX-89002 x Adv.6/2002,
ICSA-35 x Adv.3/2002 and ICSA-47 x Adv.6/2002 were significantly higher number
of green leaves than the check hybrid under 40% level of irrigation at two
locations. The crosses ATX-89002 x Adv.4/2002, ICSA-35 x Adv.4/2002,
ICSA-155 x Adv.3/2002, ICSA-155 x Adv.4/2002, ICSA-47 x RTX-2817, ICSA-47 x
Adv.3/2002, ICSA-47 x Adv.4/2002, ICSA-70 x RTX-2794, ICSA-70 x RTX-2895,
ICSA-70 x Adv.3/2002, ICSA-70 x Adv.4/2002 and Adv.6/2002 were significantly
heavier 1000-grain weight than the check hybrid under two levels of irrigation
over two locations. The crosses ATX-89002 x Adv.4/2002, ICSA-35 x Adv.3/2002,
ICSA-35 x Adv.4/2002, ICSA-155 x Adv.4/2002 and ICSA-70 x Adv.4/2002 gave
significantly more grain yield/plant than the check hybrid (Shandaweel-6) under
each level of irrigation at two locations.





2- Heterosis:



Estimates of heterosis relative to the better parent showed
that the crosses ATX-89002 x RTX-2794, ATX-89002 x RTX-2817, ATX-89002 x
RTX-2895, ATX-89002 x Adv.3/2002, ATX-89002 x Adv.6/2002, ICSA-155 x RTX-2794, ICSA-155 x Adv.3/2002, ICSA-155 x
Adv.4/2002, ICSA-47 x RTX-2794, ICSA-47 x RTX-2817, ICSA-47 x Adv.6/2002, ICSA70
x RTX-2794 and ICSA70 x Adv.4/2002 were the best crosses for earliness than the
better parent under two levels of irrigation at two locations. None of the
crosses was shorter than the better parent under two levels of irrigation either at Assiut or Sohag












locations. The crosses ATX-89002 x
RTX-2817, ATX-89002 x RTX-2895, ATX-89002 x Adv.6/2002, ICSA-35 x RTX-2794,
ICSA-155 x RTX-2794, ICSA-155 x RTX-2817, ICSA-155 x Adv.3/2002, ICSA-155 x
Adv.4/2002, ICSA-47 x RTX-2794, ICSA-47
x RTX-2817, ICSA-47 x RTX-2895, ICSA70 x RTX-2794, ICSA70 x Adv.3/2002
and ICSA70 x Adv.3/2002 had longer panicle length than the better parent under
two levels of irrigation at two locations. The crosses ATX-89002 x RTX-2817, ATX-89002 x Adv.6/2002,
ICSA-155 x RTX-2794, ICSA-155 x
RTX-2817, ICSA-47 x
RTX-2794 and ICSA-47 x RTX-2817 had wider panicle width than the better parent
under two levels of irrigation at two locations. The cross ICSA70 x Adv.3/2002
and the crosses ICSA-35 x Adv.3/2002 and ICSA-155 x Adv.4/2002 had the most
number of green leaves than the better parent under two levels of irrigation at
Assiut and Sohag locations, respectively. The crosses ICSA-47 x RTX-2794, ICSA-47
x RTX-2817, ICSA70 x RTX-2794 and ICSA70 x Adv.6/2002 had heavier 1000- grain weight than the
better parent under two levels of irrigation at two locations. The crosses
ATX-89002 x Adv.4/2002, ATX-89002 x Adv.6/2002, ICSA-35 x Adv.3/2002, ICSA-35 x
Adv.4/2002, ICSA-155 x RTX-2794, ICSA-155 x RTX-2817, ICSA-155 x RTX-2895,
ICSA-155 x Adv.4/2002, ICSA-155 x Adv.6/2002, ICSA-47 x RTX-2794, ICSA-47 x
RTX-2817, ICSA-47 x RTX-2895, ICSA-47 x Adv.6/2002, ICSA70 x RTX-2794, ICSA70 x
RTX-2817, ICSA70 x RTX-2895, ICSA70 x Adv.4/2002 and ICSA70 x Adv.6/2002 had
higher grain yield/plant than the better parent under two levels of irrigation
at two locations.

Therefore, it can be concluded that the crosses ATX-89002 x
Adv.6/2002, ICSA-155 x RTX-2794, ICSA-155 x RTX-2817, ICSA-47 x
RTX-2794,ICSA-47 x RTX-2817, ICSA-70 x RTX-2817, ICSA-70 x RTX-2895 and ICSA-70
x Adv.4/2002 had the best useful heterosis values relatively to better-parent
for most traits under two levels of irrigation at two locations.

3-Combining ability:


A- General combining
ability:

Estimation general
combining ability effects displayed that the male line RTX-2794 was the best
combiner for earliness under two levels of irrigation at two locations. The
female line ICSA-155 and the male lines RTX-2794, RTX-2817 and RTX-2895 were the better
combiners for shortness under two levels of irrigation at two locations. The
male lines RTX-2794 and Adv.4/2002 were the better combiners for increasing
panicle length under two levels of irrigation at two locations. The male line
Adv.4/2002 was the best combiner for increasing panicle width under two levels
of irrigation at two locations. The male line Adv.3/2002 was the best combiner
for increasing number of green leaves under two levels of irrigation at Assiut
location while, the male line Adv.4/2002 was at Sohag location. The female
lines ICSA-47 and ICSA-70 and the male lines Adv.3/2002 and Adv.4/2002 were the
better combiners for heavy 1000-grain weight under two levels of irrigation at
two locations. The female lines ICSA-155 and ICSA-70 and the male lines
Adv.3/2002 and Adv.4/2002 were the better parent for height yielding ability
under two levels of irrigation at two locations.

Therefore, it could be
concluded that the male line Adv.4/2002 was the best combiner among the female
and male lines under two levels of irrigation at two location, which should be
used in breeding program to pass favorable genes for improving earliness, yield
and yield components traits under optimum
(100% ET) and water stress conditions (40% ET).

B- Specific combining
ability:

Estimation specific combining ability effects indicated that
the crosses ATX-89002 x Adv.3/2002, ICSA-155 x Adv.3/2002 and ICSA-155 x
Adv.4/2002 and the crosses ICSA-35 x RTX-2895, ICSA-155 x RTX-2794 and ICS-A70
x Adv.4/2002 were the better combinations for earliness under two levels of
irrigation at Assiut and Sohag locations, respectively. The crosses ATX-89002 x Adv.3/2002
and ICSA-70
x RTX-2817
were the better
combinations for shortness. The cross
ICSA-155 x Adv.4/2002 was the best combination for increasing panicle length
under two levels of irrigation at Assiut location and 40% level of irrigation
at Sohag location. The cross ICSA-70 x
RTX-2794 was the best combination for increasing panicle width under
water stress condition at two locations. The cross ICSA-47 x RTX-2817 was the
best combination for increasing 1000-grain weight under water stress condition
at two locations. The crosses ATX-89002 x Adv.3/2002, ATX-89002 x Adv.6/2002,
ICSA-35 x Adv.3/2002 and ICSA-47 x RTX-2817 were the better combinations for
height yielding ability under two levels of irrigation at two locations.
Therefore, it could be recommended that the
crosses ATX-89002 x Adv.3/2002, ICSA-155 x Adv.3/2002 and ICSA-70 x Adv.4/2002 had
favorable specific combining ability effects for earliness and yield,
indicating the possibility of utilizing theses crosses for further
exploitation. The results obtained here concerning of general and specific
combining abilities effects indicated that the excellent crosses combination
were obtained from crossing low by good, good by good and good by good
combiners, respectively

4- proportion contributions:
Estimation of proportion contributions in this investigation
were accounted to partitions, the first, components of crosses which revealed
that the male lines (tester) and females x males interaction (line x tester)
played the major role in the inheritance of the most studied traits where, the
male lines contributed with the large percentage in the inheritance of plant
height, panicle length and 1000-grain weight at two locations and days to 50%
flowering and panicle width at Assiut location while, the females x males
interaction contributed with the large percentage in the inheritance of number
of green leaves and grain yield/plant at two locations and panicle width at
Sohag location. On the other hand, the female lines contributed with the large
percentage in the inheritance of days to 50% flowering at Sohag location. The
second part was components of crosses x irrigations interaction which cleared
that the differences in crosses
which differed from irrigation level to another
could mostly due to females x males x
irrigations interaction in all the studied traits at two locations except plant
height and panicle length at Assiut location which due to males x irrigations
interaction.

These results are of
great interest for sorghum breeder to improve maturity, seed yield and its
components to obtain genotypes that give high seed yield under water stress.