الفهرس 
Materials and mithodsOnly 14 pages are availabe for public view
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Abstract
The main objective of the present work was to evaluate some new inbred lines of maize through line x tester analysis. Thirty eight
new inbreds were isolated from different sources until 56 stage of
inbreeding. In 1995 season, the inbred lines were topcrossed to each
of three testers of different genetic base namely, Giza- 2 (broad genetic
base), S.C. 10 (mediwn genetic base) and inbred lineM 13 (narrow
genetic base. The resultant 114 top crosses along with two checks
(Giza- 2 and S.C. 10) were evaluated in 1996 and 1997 seasons in a
randomized complete block design using three replications. Data were
recorded for days to 50 % tasseling, days to 50 % silking, plant height,
ear height, ear length, ear diameter, number of rows/ ear, number of
kernels/ row, 100- kernel weight and grain yield! plant. Line x tester
analysis according to Kempthorne (1957) was practiced for the
combined data of two years.
The results of the present study combined over two years could
be summarized as follows:
1- The inbred line M 1 was the best among all studied lines for
silking date and plant height. Since it expressed the most
desirable effects over all top crosses as compared with the check
variety S.C. 10. Also, this line ranked the second best for
number of kernels! row and ranked the third best for ear height
and grain yield! plant. Inbred line M 5 was the best for ear
length, while inbred M 27 was the best for ear length and grain
yield! plant and ranked the third best for number of grains! row.
Inbred M 35 was the second best for tasseling and silking dates
and number of grains/ row. Inbred M 36 ranked the first best for
number of grains/ row and grain yield! plant, the second best for
100- kernel weight and the fourth best for silking date and for
number of rows/ ear. Inbred M 38 was the first best for ear
diameter, number of rows/ ear and 100- kernel weight and ranked
the third best for ear length.
2- The best top crosses were M 7 x Giza- 2, M 15 x Giza- 2 and
M 18 x M 13 for date of tasseling, MIx Giza- 2, M 35 x Giza-
2 and MIx S.C. 10 for date of silking, Giza- 2 with each ofMI,
M 2 and M 3 for plant height, M 2 x Giza- 2, M 30 x Giza- 2 and
M 30 x M 13 for ear height, M 5 x Giza- 2, M 4 x M 13 and M 8
x M 13 for ear length, M 5 x Giza- 2, M 8 x S.C. to and M 38 x
M 13 for ear diameter, S.C. 10 with each ofM 27, M 1,M 8 and
M 35 for number of rows! ear, M 24 x Giza- 2, M 7 x S.C. 10
and M 36 with each of Giza- 2 and S.C. 10 for number of
grains/ row, M 37 x Giza- 2, M 38 x Giza- 2 and M 38 x S.C. 10
for 100 kernel weight and M 36 x Giza- 2, M 36 with each of
S.C. 10 and M 13, M 32 x S.C. 10 and M 27 x S.C. 10 for grain
yield! plant.
3~ The highest correlation coefficients were detected for the tester
S.C. 10 and multiple tester for date oftassclina, and silking, ear
diameter, number of rowl ear, 100- kernel weight and grain
yield! plant revealing the desirability of the tester S.C. 10 as
compared with the other testers.
4- Correlation values between the two testers S.C. 10 and M 13
reached maximwn values for date of tasseling, ear diameter, 100
kernel weight and grain yield! plant, confirming the superiority
of the two testers in this study.
5- Rank correlation estimates with the multiple tester showed that
the tester Giza- 2 was the best for date tasseling and silking,
plant height, ear length and number or rows! ear. The tester S.C.
10 was the best for evaluating ear diameter and grain yield! plant,
whereas the tester M 13 was the best for the evaluation of ear
height, number of kernels! row and 100- kernel weight.
6- The highest correlation values between ranks of each two testers
were detected between Giza -2 and S.C. 10 for ear diameter,
number of rows! ear and grain yield! plant; between Giza- 2 and
M 13 for plant height, ear height, ear length and number of
kernels! row; and between S.C. 10 and M 13 for number of days
to 50% siIking and 100- kernel weight.
7- Significant mean squares due to crosses along with lines and
testers were detected for all studied traits except that of tester
mean squares for ear diameter. Significant line x tester
interaction mean squares were obtained for all traits except plant
height, ear height, ear length, number of rows! ear and 100-
kernel weight revealing that the parental lines performed
differently according to the tester to which it crossed. Significant
interaction between each of lines and testers with years were.
detected for most traits, indicating that both inbreds and testers
behaved somewhat differently from one year to another.
Significant tester x line x year mean squares were detected for
date of tasseling and silking, number of kernel! row and grain
yield! plant, revealing the hybrids between testers and lines
responded differently to growing seasons
8- Variance component estimates for GCA were appreciably larger
than those for SeA effects for most traits, revealing that the
largest part of the total genetic variability was a result of additive
gene effects.
9- The magnitude of the interaction between seA and years was
much higher than that of GCA x year for date of tasseling, ear
height, ear length, number of kernels/ row and grain Yield! plant.
This result indicated that non- additive gene action was more
biased by the interaction with environment the additive effects.
10- The inbred lines showing the best desirable GCA effects were
M 1, M 18 and M 30 and M 35 for date of’tasseling, M 1, M 18,
M 35 and M 36 for date of silking, M 1, M2, M3 and M 30 for
plant height, M 1,M 2, M 27 and M 30 for ear height, M 5, M 6,
M 3] and M 38 for ear length, M 17, M 27, M 31 and M 38 for
ear diameter, M I, M 35, M 36 and M 38 for number or rows!
ear and number of kernels/row, M 27, M 35, M 36 andM 38
- 89-
for 100- kernel weight andM 1, M5, M 27, M 35 andM 36 for
grain yield! plant.
11- The tester Giza- 2 expressed significant and negative GCA
effects for number of date of tasseling and silking, plant height,
and ear height. Parental tester S.C. 10 was the best general
combiner for ear length, ear diameter, number ofkemels/ row,
100 kernel weight and grain yield! plant. The tester M 13 was
the best combiner for number of rows/ ear. Such result
indicated that the tester S.C. 10 was the best combiner for grain
yield and most of its components.
12- The most desirable SCA effects were exhibited in the top
crosses M 15 x Giza- 2, M 31 x M 13 andM 7 x S.C. 10 for date
tasseling, M 31 x M 13, MIx S.C. 10 andM 8 x S.C. 10 for
date of silking,M 36 x S.C. 10,M 18 x S.C. 10 andM 5 x Giza-
2 then M 17 x M 13 for plant height;M18 x S.C. 10,M 13 xM
31 and M15 x S.C. 10 for ear height,M 4 x S.C. 10,M 8 x S.C.
10 andM 5 x Giza-2 for ear length,M 23 x Giza- 2, M 8 x S.C.
10 and M 38 x M 13 for ear diameter,M 19 x M 13,M 17 xM
13 andM 27 x S.C. 10 for number of rows! ear, M 24 x Giza- 2,
M 3 x S.C. 10 andM 7 x S.C. 10 for number of kernels! row, M
11 x S.C. 10, M 19 x Giza-2 andM 20 x Giza. 2 for 100-
kernel weight and M 4 x S.C. 10,M 22 x Giza- 2, M 13 x S.C.
10, M 14 x S.C. 10 and M 32 x S.C. 10 for grain yield! plant.
13- The discriminating power of the tester based on the range in SCA
effect between the testcross, number of significant SCA effects
and the highest favorable SCA effect revealed that, for date of
tasseling, the tester Giza- 2 expressed the highest number of
desirable SCA effect and showed the highest negative SeA effect, while the tester M 13 exhibited the widest range of SCA effects. For date of::silking and number of rows! ear, the best
tester in the three estimates was M 13. For plant height, ear
height, ear length, and 100- kernel weight, the best tester was
S.C. 10 in at least two estimates. For ear diameter and number of
grains/ row the best tester was Giza- 2. For grain yield/plant, the
tester S.C. 10 expressed the highest desirable SCA whereas the
tester Giza- 2 exhibited the widest range between seA effects.
14- The most desirable heterotic effects for grain yield! plant relative
to the check Giza- 2 were recorded for the top crosses M 36 x
S.C. 10 (40.86%), M 32 x S.C. 10 (39.68%), M 27 x S.C. 10
(39.57%), M 36 x M 13 (39.04 %) and M 13 x S.C. 10
(31.34%). whereas, the best heterosis values relative to S.C. 10
were detected for the top crosses M 36 x S.C. 10 (25.91%),
M 36 x Giza- 2 (25.05 %), M 32 x S.C. 10 (24.86%), M 27 x
S.C. 10 (24.76%) and M 36 xM 13 (24.28%). Therefore, these
crosses are prospective in maize breeding programs.