الفهرس 
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Abstract
Eight inbred lines descendant from the cross (Giza 83) I (line
22/80), in addition to the two parents of the cross were grown at
seven locations. i.e.; Sakha. Bahtim. Giza. Sids. Maghagha,El-Ioussia
and El-H1nshah in 1987 season. A randamized complete block design
with six replications was used. The standard analysis of variance
and stability of preformance were made for each of the characters
under the study. The result,s obtained could be summarizedas follows:
1- The relative magnitudes of the genotype-environment interaction:-
Highly significant mean squares for environments were obtained
for all characters. The genotypic differences were significant or
highly significant for all characters under study except number of
bolls per plant, seed cotton yield and lint yield characters. The
mean squares of genotype-environment interaction were significant
or highly significant for all characters except number of days to
first flower. earliness percentage and the 2.5 % span length. These
results indicated that cotton as well as other crop varieties often
showeddifferent responses ~len grownunder different environments. ;
11- The genotypic stability for different genotypes : The relative ranking o.f genotypes according to their mean performance
over the seven environments was not the same for all characters.
Lines 50/85 and 48/85 were the earliest and highest yielding
amongthe other genotypes.
• iWl.threspect to genotyp:1cstability analysis. all of the cbaracters
(except, num.berof dSJ·s to first flower, earliness percentage
and 2.5% span length) show
ponent of variance (the de
that the relatively unpredictable com-
,.from linear response. A.. ) of the
genotype-environment may be more important than the
relatively predictable compon nt (the linear response. ~ ).
IIEstimations of genoty c stability revealed varying degrees
of stability for the genotypes. This study shows that the
most stable genotype over e seven sampled environments was line
63/85 which exhibited hest number of stable characters. followed
in a descending variety and lines. 44/85. 53/85.
50/85, 22/80, 59/85, 48/85. Giza 83. and 61/85. Apparently,
the lines with high mean valu had below average degrees of stability,
Ilines with poor mean performs ce had above average stability and lines
Many workers reported t the stability with which the plant
with average mean performance howed average stability in this study.
breeders are concerned does imply general constancy of phenotype
in varying environments, but stability in agriculturally
important characters (Allard and Bradshaw, 1964; Eberhart and Russel, 1966; Tai, 1971). Therefore. the genotypes
53/85, 44/85 and SO/85 which ibited high yielding ability and were
stable in one or more of th traits studied in the present investigation
could be selected. III- Estimation of heritabilit enetic advance under selectionand enetic coefficient 0 variabilit ..1- High heritability value (over 50%) were observed for earliness
/characters. boll weight. lint seed index, lint index and
all of the fiber propertie The high heritability values were
approximately, consistent f all the seven environments. Moderate
heritability estimates, (fro 30 to 50 %), were obtained for number
of bolls per plant. Howeve, low heritability values (below 30%)
were obtained for yield chara terse
2- High excepted genetic advance (over 7%) were observed for the
position of first sympodiumand seed index. Moderate genetic gains,
(from 5% to 7%) were est :ed for earliness percentage, number of
bolls per plant, and micronaire reading. While, low
genetic gains, (below 5%), w e calculated for days to first flowering,
yield characters, lint perce tage , lint index and all the other fiber
properties.3- The genetic coef£ici at of variability was intermediate’ only
for the position of first, :rmpodiWDh,owever, it was small for the other characters.