Genetic Divergence and Correlation Study in Sesame (Sesamum indicum L.) Genotypes
No Thumbnail Available
Date
2008-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
A field experiment was designed at the research site of Werer Agricultural Research
Center in the 2007/8 cropping season to assess genetic divergence and character
associations among 13 agro-morphological traits of 100 local and exotic sesame
(Sesamum Indicum L.) genotypes. The result indicated the existence of a wide variability
among the genotypes for all the measured characters. The highest PCV and GCV
estimates were observed for oil yield per plant (54.47%, 37.30%) followed by seed yield
per plant (54.23%, 35.77%), number of primary branches (42.93%, 32.37%) and distance
to the first pod (41.69%, 26.01%), respectively. More than half of the characters showed
heritability (broad sense) values of greater than 50% and higher estimates of heritability
values were recorded for days to flowering (62.45%) followed by number of primary
branches (56.68%), 1000 seed weight (56%), capsule length(55%), days to maturity
(54.865) and oil content (53.10%). Higher values of genetic advance that could be
expected from selecting the top 5% genotypes, as percentage of mean was recorded for
oil yield per plant (92.84%) followed by number of primary branches (50.31%) and seed
yield per plant (48.64%). Higher estimates of broad sense heritability together with high
genetic advance was observed for number of primary branches, number of capsules and
seed yield and oil yield per plants, indicating the possible preponderance of additive gene
action. Seed yield had shown significant and positive PCC and GCC with number of pods
per plant (0.849, 0.967), thousand seed weight (0.744, 0.865), oil yield per plant (0.997,
0.998), plant height (0.326, 0.263) and oil percent (0.361, 0.551) while, it had significant
but negative PCC and GCC values with number of seeds per pod (-0.281,-0.585) and
days to flowering (-0.369, -0.454) respectively. Path analysis of seed yield revealed that
number of pods per plant and number of primary branches had a positive direct effect on
seed yield. Yield components 1000 seed weight, plant height and days to 50% flowering
had negative values of direct effects although seed yield was counter balanced by higher
positive indirect effects exerted through number of pods per plant, plant height and days
to 50% flowering. Path analysis was also computed using oil yield as a dependant
character and characters number of pods and seed yield per plants had positive direct
effects on oil yield per plant. On the other hand negative direct effects were observed for
1000 seed weight and oil content, however these negative values were found to be
counter balanced by positive indirect effects of the other component traits. The principal
component analysis was performed and the first three principal components were found
to explain 73% of the overall variability existing among the test entries. The major
contributing factors for the total variability were found to be days to 50% flowering, days
to maturity, distance to the first pod and number of primary branches in order of
importance. Cluster analysis grouped 100 genotypes into eight diversity groups
containing 39, 43, 3, 9, 3 genotypes in that order while, the remaining three clusters had
single accession each signifying the fact that efficient germplasm management can be
achieved through avoiding redundant accessions. Generally the study had shown the
existence of high genetic diversity among the evaluated accessions that could be utilized
for future breeding programs. Further investigations are needed to study the diversity of
the crop at molecular levels to ascertain the finding of this study.
Description
Keywords
Biology