الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
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SUMMARY
This study was conducted at Giza Agricu1 tur~l1 Research
Center during 197,8/79 and 1979/80 growing seasons •
The objective of this investigation was to determine
the extent of heterosis over mid- and better parents, the
genetic system controlling growth characters and yield
components, and the relationships among growth and yield
attributes. In order to cover this information, dia11e1
cross analysis involving diverse parents, namely, Bonus,
Mari, Ris~ 1508, Bl, Kervana, and WI 2197 .erE~ used •
The main results are summarized as fo11oWl:l:
1) Effect of heterosis :
Heterosis estimated as the percent ~Lfrerence
between the F
l
and Mid- parent showed posit:Lve and
signi ficant effect for days to heading (26.:~). plant_
heilht (29.45%). peduncle length (29.95%). flag leaf
area (54.72%). spike length (15.85%), IOOO-kernel weight
(17.84%), number of kernel per spike (24.36%), spike
weight (27.25%), grain protein content (11.54%), grain
yield per plant (4l.86%) and harvest index (27.12%).
Significant negative heterosis effecte: was found
for number of spikes per plant (-31.72%), grain DBC
value (-8.17%). total aerial biomass production
(-21~85$) and straw weight per plant (-3lt,96%).
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Heterotic effects estimated as percent diffl3rence
from the better parent (HeterobeltiosiS) were significant
for days to heading (53.61%), peduncle length
(12.23%), flag leaf area (39.08 %), spike lengt’n
(13.87%), lOOO-kernel weight (15;18%), number of
kernels per spike (16.61%), spike weight (26.89%),
and grain yield per plant.
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2} Genetic analysis:
The analysis of variance for Wr-Vr showed t.hat
the di fferences between arrays were signi ficant for
four traits; days to heading, pedun.clelength ,::pikelength
and number of kernels per spike. This result indicated
that one or more 0f the assumptions underlyillg
Hayman analysis were not satisfied. Therefore, the
genetic estimated will be less accurate for these traits
•
Additive genetic variances were more 1mporitant
than dominance genetic variances in t~e inher1 t’lnce
of plant height, number of spikes per plant, gr.dn
protein content, grain DBC value, straw protei:n cont:-
ent ,:total aerial biomass production, straw weight
per plant, and grain yield per plant, Additive and
do.tnance types of genetic effects showed an eq~
importance in inheritance of nag leaf area, 1000 -
~ernel weight, spike weight aDd harvest index •
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The average degree of dominance was fou~d to be
over-domt-nanc e for flag leaf ar-ea , straw protein cont.ent
and harvest index; complete dominance for harvest index;
and partial dominance for tpe rest of the traits.
The negative and positive alleles were not equ~lly
distributed among the parental population in all cases.
The proportion of dominant and recessive genus, suggested
that the dominant genes are in excess in the parents
for all character except spike weight, where rece2~sive
genes are predominant.
Plant ~eight t flag leaf area, number of spikE~S per
plant and grain DBC value were found to be under the
control 0 t 1-2 groups 0 f genes ex-hibiting dOlD1nllUce.
MeanWhile, IOOO-kernel weight, spike-weight, atrn.•protein
content and harvest index togeather with its compcments
were found to be under the control 0 f ODe group 0 j~ genes
exhibiting dominance.
High narrow sence heri tab111 ty value was detE~cted for
lOOO-kernel weight. Low values ot narrow sense heJ~tability
were observed for number of spike per plant, spike weight,
straw protein content and grain yield per plant I Irhile the
rest at the traits , exhibited interaediate narrolr sence
heritability values.
3) Correlations:
Harvest index showed. significant positive g4!Dotypie
correlations with each of grain yield per plant,IOOO-kernel
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weight and spike weight, while it showed significant
negative genotypic correlations with total aerial biomass
production, straw yield per plant, grain protein content,
number of spikes per plant a~d flag leaf aer.a. Positive
genotypic correlations were obtained between grain yield
per plan t and each 0 f lOaD-kernel weight, spi.ke wei ght ,
peduncle length, plant height and total aerial biomass
production. Negative genotypic correlations we~re found
between grain yield per plant and grain pr-ot ef.n content.
Grain protein content was positively and signt ficantly
associated with number of spike per plant, flag leaf
area, and days to heading, while it was negatj.vely and
significantly associated with harvest index, grain yield
and yield components. Days to heading showed pesitive
and significant genotypic correlations with each of
spike length, total aerial biomass production, straw
yield per plant, plant height, number of kernels per
spike, number of spikes per plant and grain protein
content. Significant negative phenotypic correlations
were detected between days to heading .endharves .. index.
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