This study was conducted with the objective of estimating combining ability and
gene action for some quantitative characters in flax. In season 2004/2005, the six
parents (P,=S.413/3/3/1, P2=S. 400/4/412, P3=S.40211, P4=S.421/6/4/5, Ps=
R0r1ania10 and Pe= Romania 20) and their 15 Ffs progenies were evaluated in a
randomized complete block design with three replications at Giza Res of the ARC.
Station Farm. The collected data indicated that the additive effects were more
important than non-additive effects for both of plant height, technical length and No. of
basal branches per plant indicating that possible response to selection for these
traits. Ps and Ps provide to be the best general combiner for most characters of straw'
yield and its components except for No. of basal branches. The next high combiner
was P, for plant height, technical length and No. of basal branches. From these
results, it could be noticed that these parents are consider good parents to improve r
straw yield/plant. The specific combining ability estimates indicated that there was no
cross combination which was consistently good for all the straw yield per plant and its
components, except for one cross only (Ps=Pe) exhibited highly significant and
positive SCA effects for all traits of straw yield and its components. Therefore, the
cross PsXPe may prove useful for simultaneous improvement of these traits.
The mean squares due to general and specific combining ability were highly
significant for seed yield and all its components. These results revealed that the
inheritance of these characters were mainly controlled by additive genetic effects of
genes. The parents, P" P2 and P3 showed highly significant and positive general
combining ability effects for seed yield and most of its components (No. of capsules
and 1000-seed weight). Indicating that the use of these parents in flax breeding
programs could increase seed yield per plant. The specific combining ability
estimates indicated that there was no cross combination which was consistently
good for all characters. Three crosses, P,XP2 (for seed yield), P,XP3 and P2XP3 (for
1000-seed weight and No. of seeds per capsule) included high x high general
combiner parents. indicated that these crosses would be interesting and prospective
for the future in flax breeding program for improving seed yield per plant.
Phenotypic (rp) and genotypic (rg) correlation coefficients between straw
yield and both of plant height and technical length were significant and positive. Also,
the significant positive correlation among plant height and technical length was
present, indicating that the breeder can utilize such correlated response to obtain high
straw yielding genotypes through selection for one or more of these characters. On
the other hand, seed yield per plant was significant positively correlated with No. of
basal branches. Also, No. of capsules per plant exhibited highly Significant and
positive correlation with 1000-seed weight.