الفهرس 
Material and methodsOnly 14 pages are availabe for public view
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Abstract
L fNTRODUCTIO
Indigenous breeds of chickens have the advantages of good adaptation to
local nvironrnent and naturalgenetic resi taaec IQ some serious diseases such
as Marek’s disease. Morover, many people still prefer the la 10 and flavor of
indigenous chicken’s meat and eggs, hese strains usually 11’ere not subjected to
intensive selection program andconsequently, high additive and non-additive
genetic variations appeared to have meaningful effect (Iraqi IlJ at; 2000). This
was an encouraging factor 10 cross our 1000il strain together.
Some studies ·(Sbebl.e et 01., .’90; Nawar and Balie EI-DecD, 2000 and
Iraqi, 2002) reported that n1QSt of the native breeds had high non-additive
genetic variance lind therefore, posslbiljty of improvement of these breeds
through erossbr cding is evident. Heterosis has become II routine tool for poultty
breeders 10 produce progeny that exhibit more desirable pheeotvpes than those
of their parental populations. Th.eoretkllllY, tbe magnitude of heterosis is
inversely relat e’ICi to lie degree of genetic rresemblanco between plI.relllal
’populations (WiJlham and Pellak, (985) and is ’peeled to be proportional to
the degree ofheterozygosil)’ of the crosses ( herida~. 1981), thus heterosis isa
result or non-additive generic effects, but: it is often around 10% or greater for
egg production traits llirfoU, 11)90).
Egg production is a complex metric trait shov ing many variations during
(he period of production of the pullet The study of egg production and its
rel t d traits such as age lind body weight lit sexual maturity, rale of laying and
clutch size attra led the attention of several investigators who found that there
were wide variation in these traits among differenl breeds and/or s!mi;ns of
chickens (AMel GAWll!’1, 1981; EL-Labban at a1., 1991; Ho ’un, 199?j Ali at
al., 1999j IE (luda”. 2000 and ~~c:ries at., 2007). Partial recording of egg
production ill pullet is used to enhance and 10 increase the efficiency of genetic