A half diallel set of crosses among six inbred lines of sweet corn was evaluated to study heterosis and combining ability among plant height, ear height, ear diameter, number of rows per ear and ear yield per plant. The study was carried out at the a
gricultural research center in, GCSAR, Lattakia, Snoubar Jableh, during the 2010, 2011 seasons.
Result showed that almost all crosses expressed a significant positive heterosis effect for ear yield per plant relative to mid parents and better parents; whereas, the highest positive significant percentage of heterosis for ear yield per plant were expressed by the crosses (L4xL6) which gave (198.70%, 176.81%) and (L4xL6) which gave (196.94%, 168.56%), over mid parents and better parents, respectively.
The ratio (σ2GCA/σ2SCA) which was less than (1) showed that the non-additive gene action was more important than the additive gene action in all traits except plant height and ear height. The inbred lines L3 (17.061) and L4 (12.011) seemed to be the best general combiners for ear yield. Also, based on SCA effects, many of single crosses were identified as superior for ear yield, and the best hybrid was L3xL5(50.173).
A half diallel set of crosses among six inbred lines of maize were evaluated at the
Maize Research Department (G.C.S.A.R.) in Damascus Governorate during 2010 and 2011
growing seasons to estimate heterosis and combining ability components for the n
umber of
rows per ear, number of kernels per ear, ear length (cm), ear diameter(cm), 100-kernel
weight (g), and grain yield (ton /hec).
The inbred lines, crosses, general combining ability (GCA) and specific combining
ability (SCA) mean squares were highly significant for all the studied traits, showing the
existence of a genetic variance among lines.
The ratios of GCA to SCA detected for the studied traits showed the dominance of an
additive gene action for all the studied traits except for 100-kernel weight and grain yield
which showed the predominance of a non-additive gene action.
The heterosis percentage for the studied traits was significant based on mid and
better parents.
The GCA effects showed that the lines CML.317, CML.371, CML.373 and
CML.367 were good general combiners for grain yield, while the SCA effects showed that
seven hybrids were the best F1 cross combinations such as (CML.317×CML.371) for grain
yield.
This research aimed to evaluate the general and specific combining ability
components for six inbred lines and 15 hybrids produced by a half diallel cross method,
and was conducted during 2010-2011 seasons, in the Department of the Maize Researches
at G.C.S.A.R. Damascus .
The evaluation included the grain yield, ear height, ear length, and silking under two
different treatments of nitrogen fertilizer (1- addition of 50% of N-fertilizer with sowing
and the other 50% one month after sowing. 2- addition of 50% of N-fertilizer 18 days after
sowing and 50% one month after sowing).and 3 replicates.
Results indicated that:
Mean squares of inbred lines, and hybrids were highly significant for all studied
traits under two adding dates of nitrogen fertilizer, which indicated the presence of genetic
distance among parental lines.
The ratios (
2
GCA/
2
SCA) showed that additive gene effect was more important than
non-additive gene effect in controlling all studied traits except grain yield which showed
dominance of non-additive gene effect under tow dates.
Many of significant positive GCA effects were obtained for all traits, therefore, it
could be concluded, that the inbred lines CML.330, IL.26-09 and CML.334 seemed to be
the best general combiners for grain yield.
The hybrid (CML.368 × IL.215-09) had showed the best specific combining ability
effects for grain yield under the first date, while the hybrid (CML.330 × IL.26-09) showed
the best SCA effects under the second date.
The second adding date of nitrogen fertilizer (50% 18 days after sowing and 50%
one month after sowing) had surpassed of the first date (50% with sowing and 50% one
month after) with significant effects for grain yield trait.
A half diallel set of crosses among six highly diverse barley (Hordeum
vulgare L.) genotypes were evaluated at Karahta station of field crops research
(GCSAR) Damascus Governorate, during 2010-2011 and 2011-2012 seasons to
study heterosis and comb
ining ability components for plant height, grain yield
per plant, number of spikes per plant, number of grains per spike and
thousand kernel weight.
This research has been carried out at the experimental Station of
Agriculture Faculty, Damascus University during the period of 1998-2000. Five
parents were selected from the Cotton Office Germplasm (Aleppo40, Raqua5,
Dir22, Daltabain50, 88G6104)
to examine the inheritance of some
morphophysiological, yield, and quality related traits. In1998, the five parents
were hand-crossed in all combinations (with no reciprocals) generating ten F1
hybrids. During 1999, the ten crosses and their parents were planted to produce
F2 seeds. In 2000 the F1s, F2s, and their parents were grown in a randomized
complete block design with two replications.
Heritability estimates in broad sense showed that the earliness traits possess
the highest values, followed by total and actual bolls number, indicating the
importance of additive gene action in the inheritance of these traits. Whereas,
heritability values for other traits were markedly different, revealing the
genetic diversity of these hybrids parents.
High estimates of expected genetic advance were found to be associated with
high heritability estimates for total and actual bolls number, indicating that
direct selection should be effective for these traits. On the other hand,
improvement of traits, possessing intermediate estimates of genetic advance
and high heritability estimates, such as total bolls number, harvest index,
flowering earliness and fiber elongation in some studied hybrids, through direct
selection might be less effective. The results suggest that traits with high
heritability estimates associated with low estimates of genetic advance; and
those possess intermediate estimates of heritability and genetic advance or low
estimates of both parameters are most likely controlled by non-additive genes,
therefor, direct selection might not be effective for improving these traits.
This study was carried out during 2010-2011 growing seasons at the
Maize Researches Department (G.C.S.A.R.) Damascus. To estimate
heterosis for number of rows per ear, ear length, ear diameter, 100- kernel
weight, and grain yield.
Half diallel set of crosses between six inbred lines of maize were executed at Maize
Research Department, General Commission for Scientific Agricultural Research
(GCSAR), Syria, during 2010 and 2011 seasons to study heterosis, general and
specific
combining ability components for grain yield (ton/ha), ear height, length and
diameter (cm), and silking date (day) compared with control varieties Basel-1 and
the hybrid Spirou S-4- 985 to identify the best hybrid in terms of yield. Randomized
Completely Block Design (RCBD) was used with three replicates.
A half diallel making design was used to determine combining ability and heterosis of six
chickpea lines and their hybrid combinations with R.C.B.D. in three replication for seed
yield per plant, number of pods per branch, pods number per plant, fi
rst pod height and
100- seed weight, during 2015 and 2016 seasons, at the research Center of Al-Gab
(G.C.S.A.R). Genotypes, general (GCA) and specific (SCA) combining ability mean
squares were significant for all studied traits. The ratio σ2
GCA / σ2
SCA were detected for all
traits and showed that non- additive gene action was more important than additive gene
action in controlling all studied traits. GCA effects showed that the lines الإسباني was good
general combiner for traits:seed yield per plant, pods per plant, 100- seed weight, days to
maturity, protein per cent. SCA effects showed that(Algerian×Spanish) hybrid was the
good specific combiner for seed yield per plant, pods per plant, 100- seed weight, harvest
index. On the other side(Algerian×Spanish) was showed significant desirable heterosis
values for seed yield per plant and 100- seed weight, days to maturity, harvest index.
