الفهرس 
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Abstract
GENETIC STUDIES ON SUNFLOWER
The open pollinated sunflower (Helianthus annuus L.) is
one of the main oil crops throughout the world because of its
edible and industrial importance and its adaptability for
different environments.
The present investigation under study was carried out
during the period from (1987-1989). The main objective of this
investigation was to study the evaluation of four sunflower
populations~ se and their crosses using diallel analysis to
determine the most effective breeding methods that fit this
material. The study also included estimation degree of
heterosis, inbreeding depression, additive and non additive
alleles controlling the studied traits, heritability and
estimation of both genotypic and phenotypic correlations among
oil percentage and other studied traits.
The material used included four cultivars; Giza-1,
Sunbred, Vniimk and Ala, the parents and their crosses were
evaluated in an experiment using randomized complete block
design with three replications.
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The data were recorded on the following characters; Yield
per plant, 100-seed weight, head diameter. Plant height, stem
diameter, days to flowering and oil percentage.
The data were analyzed using Griffing’s procedure,
(1956), method-2 model-1.
The results obtained could be summarized as follows:
1. General combining ability variances for all of the
studied traits were the predominant component and played
the major contribution in inheritance of all traits.
Specific combining ability variance was also present of
the studied traits and highly significant for all the
studied traits with the exception of stem diameter.
2. General combining ability effects varied from one parent
to another with either negative or positive values.
specific combining ability effects was observed for most
crosses with either negative or positive values.
3. Heterosis estimates relative for mid-parent showed
significant positive estimated for yield/plant character,
while for 100-seed weight trait showed significant
positive andjor negative estimates. For days to flowering
trait one out of the six values showed s igni fican{:
negative values. As regarding to plant height trait most
values showed significant positive estimates. For stem
and head tljametm lxaits signifi