PhD

The present study entitled “Development of superior varieties in white seeded
sesame for seed yield and oil content’ was carried out at ORARS, Kayamkulam
during 2019-2022. The objectives of the study were collection and evaluation of
various genotypes of white seeded sesame for seed yield and oil content, to study
the heterosis and combining ability and to develop superior segregants of white
seeded sesame genotypes with high seed yield and oil content. The study consisted
of five experiments.
In the first experiment, thirty white seeded sesame genotypes obtained from
different parts of India were assessed for genetic variability, heritability, genetic
advance, correlation and path analysis of seed yield and thirteen other traits.
Analysis of variance showed significant differences among the genotypes for all
investigated characters. The genotype Gu. Til 4 and PCU-37 recorded highest seed
yield plant-1
and oil content respectively. The seed yield plant-1
exhibited the highest
GCV (43.59 %) and PCV (49.72%). Heritability was high for all the characters
except maturity days (49.48%). The genetic advance was high for all the characters
except 1000 seed weight, days for 50 per cent blooming, capsule length, protein
content, oil content and maturity days. High heritability coupled with high genetic
advance as per cent of mean was recorded for seed yield plant-1
, number of capsules
per leaf axil, leaf area, dry matter production, number of capsules plant-1
, primary
branches plant-1
, number of seeds capsule-1
and height of the plant indicating
additive gene action. Hence selection based on these characters may be rewarding.
The association analysis revealed that seed yield plant-1
has significant and
positive correlation with number of capsules plant-1
, dry matter production, height
of the plant, number of capsules per leaf axil, leaf area, primary branches plant-1
,
number of seeds capsule-1
and capsule length. The high significant positive direct
effect was recorded by number of capsules plant-1
, number of seeds capsule-1
,
number of capsules per leaf axil and height of the plant with seed yield plant-1
.
Among the thirty genotypes evaluated in experiment I, five high seed
yielding genotypes (lines) viz., Gu. Til 4, VRI-3, Punjab Til No.2, RT-346 and
PCU-42 and three genotypes with high oil content (testers) viz., PCU-37, PCU-38
and NIC-8322 were chosen and crossed in a Line x Tester mating design
(experiment II)
In experiment III, fifteen hybrid combinations obtained were raised in the
field along with the parents and evaluated for heterosis and combining ability. The
analysis of variance showed significant differences for all the characters among
parents and crosses. The cross Gu. Til 4 x NIC-8322 manifested highest seed yield
plant-1
followed by the crosses Gu. Til 4 x PCU-41 and RT-346 x PCU-37.
Combining ability analysis demonstrated the dominance of non-additive gene
action for most of the traits except number of capsules per leaf axil. Among the
parents, Gu. Til 4 was the good general combiner as it displayed highly significant
and positive gca effect for seed yield plant-1
. Among the crosses, highest significant
sca effect for seed yield plant-1 was manifested by the cross RT-346 x PCU-37
followed by Punjab Til No.2 x PCU-37 and VRI-3 x PCU-41. The highest
magnitude of standard heterosis along with high per se performances for seed yield
plant-1 was observed in the cross Gu. Til 4 x NIC-8322 followed by Gu. Til 4 x
PCU-41 and RT-346 x PCU-37.
In experiment IV, F2 seeds obtained from the F1 hybrids were raised in the
field. The highest number of transgressive segregants in the F2 generation for seed
yield plant-1 was observed in the cross VRI-3 x PCU-41. From the F2 population,
110 transgressive segregants which were superior in yield were selected and
forwarded to F3 generation. Forty superior segregants were identified and selected
based on plant growth habit and yield contributing parameters. From the forty
segregants, seven superior segregants with high seed yield, oil content and protein
content were selected from six families of the crosses viz., Gu. Til 4 x NIC-8322,
VRI-3 x PCU-41, Punjab Til No.2 x PCU-37, Punjab Til No.2 x PCU-41, RT-346
x PCU-37, PCU-42 x PCU-37. These superior segregants may be forwarded to
advanced generations and yield trials for confirming their superiority and release as
a variety.