Two cros.ses of soybean (CallandX ،Jardin) and (Elgin X Hardin), each withsix populations (P1, P2, Fi, F2. BC) and BC2) were testedfor earliness, yield ànd ils
components. Signijicant positive heterolic effects were detected for all traits except
number of days to maturity which gave significant negative heterotic effect in both
crosses. Overdominance towards the higher parent was obtained for number of branches
per plant, first pod height and 100-seed weight in the first cross, number ofpods per
plant, number of seeds per plant and seed yield per plant in both crosses. Absence of
dominance was detected for number of days to inflorescence in the second cross. Partial
dominance, towards the higher parent was detected for other traits. Signijicant positive
values of inbreeding depression (7. D.) were detected for number of branches per plant,
plant height, number ٍf seeds per plant, number of pods per plant and seed yield per plant
in both crosses and first pod heLghl and ، 00-seed weight in the second and first crosses,
respectively. Jnsign ،Ji cant I. D. value was obtainedfor number of days to inflorescence in
the first cross. While, the other cases رave sign ijicant I. D. values. The additive gene
effects were signijicant for all traits. Also, significant dominance values were obtained ,
f or all traits except number of branches in the first crosses. Signijicant estimates for one
or more of the three types of epistasis in both crosses were detected for all traits. High
heritability values in broad sense were obtained in both crosses for all traits except
maturity period, number of seeds per pod, seed yield per plant in the second cross and
100-seed weight in the first cross which had a moderate heritability values. Moderate
heritability values in narrow sense were obtained for most traits. The predicted genetic
advance (expressed as a percentage of the mean) was rather moderate for all cases except
maturity date and maturity period in both cross. Meanwhile, flowering date and 100-seed
weight in the first cross showed low genetic gain.
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