3 research outputs found
Combining ability and heritability of selected rice varieties for grain yield, its components and grain quality characters
Molecular characterization and genetic diversity analysis of different rice cultivars by microsatellite markers
A total of 52 rice SSR markers well distributed on 12 chromosomes were used
to characterize and assess the genetic diversity among ninety four rice
genotypes. The total number of polymorphic alleles was 361 alleles with the
average of 5.86 alleles per SSR locus. The study revealed that some markers
such as RM276 and RM5642 on chromosome 6 and RM14 and RM1 on chromosome 1
have more than 9 observed alleles compared to other primers like RM16, RM207,
RM208 and RM317 with 3-4 alleles. The highest and lowest PIC values were
observed for primers RM276 (0.892 and RM208 (0.423) respectively. Using
Shannon´s diversity index, a mean genetic diversity of 1.641 was obtained
from the analysis, indicating a high level of genetic variation among these
cultivars. Cluster analysis using the complete linkage method based on
jaccard similarity coefficient revealed that all genotypes were classified to
nine clusters at genetic similarity level of 0.010.75, which contained 12,
16, 2, 18, 3, 6, 16, 10 and 11 varieties, respectively. Results of
discriminant analysis showed that the nine cluster groups were confirmed at
high levels of correct percent (96.8) and revealed true differences among
these clusters. As a final result from this study, we selected eight
cultivars from different cluster including Daylamani, Tarom mohali (landrace
rice cultivars), RI1843046, Back cross line, RI184472, RI184421 (promising
cultivars), Line 23 and IR50 (IRRI lines) as parents. All of the selected
cultivars will be arranged in complete diallel design to obtain combining
abilities, gene effects and heterosis for each important morphology and
physico-chemical characters
Combining ability and heritability of selected rice varieties for grain yield, its components and grain quality characters
This study was conducted to determine the combining ability and heritability
of rice grain yield, its components and some grain quality traits such as
amylose content (AC), gelatinization temperature (GT), gel consistency (GC)
and head rice recovery (HRR). The study was commenced by crossing the
selected rice varieties based on a full diallel mating design. The F1 was
harvested at the end of the season. In the following season, the crossed,
reciprocal and parental lines were planted in randomly complete block design
with three replications. Analysis of variance indicated that genotypes were
significantly different for all traits. The diallel analysis by Griffing`s
method showed highly significant differences for GCA for number of panicles
per plant (PN), amylose content, gelatinization temperature and head rice
recovery. Highly significant differences were also observed for both SCA and
REC for all evaluated characters. The results showed that the grain yield
(GY), number of filled grains (FGN), 100-grain weight (HGW) and GC were
controlled by non-additive gene action, while the inheritance of PN, AC, GT
and HRR were largely controlled by additive gene effects, although non-
additive genetic components and reciprocal effect were also involved, which
suggest that a selection process could be done in the early generations. The
two improved lines (RI18442-1 and RI18430-46) were found to be good general
combiners for GY and FGN, while the best combiners for PN was Tarom Mohali
and IR50 and for HGW was RI18430-46. The best combinations for GY were
RI18430-46 × IR50, Tarom Mohali × RI18447-2 and Daylamani × RI18430-46. The
good hybrids were Tarom Mohali × IR50, Line23 × RI18447-2 and Line23 ×
Backcross line for AC. Narrow sense heritability showed that the GY and GC
had the lowest values while the other traits had either moderate or high
heritability, which indicates selection in the early generations could be
done to fix the favorable genes. In present study, narrow sense heritability
was high for AC and moderate for GT, PN and HRR