STUDIES ON GENETIC ARCHITECTURE AND RESPONSE OF SELECTION FOR YIELD AND YIELD ATTRIBUTING TRAITS IN LINSEED (Linum usitatissimum L.)
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Date
2018
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Birsa Agricultural University, Ranchi, Jharkhand-6
Abstract
A study entitled “Genetic architecture and response of selection for yield and yield attributing
traits in linseed (Linum usitatissimum L.)” was conducted at departmental research farm, BAU, Kanke,
Ranchi during Rabi 2016-17 to investigate about variability, nature and magnitude of gene effects,
their interactions, heterosis and inbreeding depression for ten yield and yield attributing traits
following six parameter model generation mean analysis. Sixty nine treatments consisting eight
parents, 15F1s, 15F2s, 15BC1s, 15BC2s and one check (T-397) were sown in randomized block design
with three replications. Simultaneously, in a separate experiment using two backcross populations viz.,
(Meera x T-397) x Meera and (Shekhar x T-397) x Shekhar, response of selection study was done
evaluating variability, correlation coefficient analysis, path coefficient analysis etc. Five hundred
BC1F2 plants were selected randomly constituting base population and out of this, hundred superior
plants were selected considering all the selections criterion and whose progenies rows were grown
making BC1F3 population in both the crosses.
The analysis of variance revealed highly significant differences among the treatments for all
the characters under study. An estimate of GCV and PCV for all characters revealed that the PCV was
higher than their corresponding GCV, indicating presence of variability among the treatments for yield
and yield attributing traits and characters like, number of primary branches per plant, number of
capsules per plant and seed yield per plant showed high PCV and GCV. High heritability coupled with
high genetic advance as percent of mean was obtained for number of capsules per plant and seed yield
per plant.
With the help of scaling and joint scaling test presence or absence of epistasis and adequacy of
additive-dominance model respectively was checked and accordingly six parameter model was
followed for estimation of gene effect as well as presence of non-allelic interactions. Epistasis was
indicated in almost all the fifteen crosses for the studied traits. Duplicate epistasis was more prevalent
than complementary epistasis.
Significant and desirable heterosis over mid parent was observed in four crosses for days to
50% flowering, two crosses for days to maturity, three crosses for plant height, two crosses for number
of primary branches per plant, twelve crosses for number of capsules per plant, three crosses for
number of seeds per capsule, seven crosses for capsule diameter, twelve crosses for each seed yield per
plant and 1000-seed weight and eleven crosses for oil content. Heterosis over better parent was
observed significant and in desirable direction for seven crosses for days to 50% flowering, five
crosses for days to maturity, four crosses for plant height, two crosses for number of primary branches
per plant, nine crosses for number of capsules per plant, two crosses for number of seeds per capsule,
one cross for capsule diameter, eleven crosses for seed yield per plant, twelve crosses for 1000-seed
weight and eight crosses for oil content. Similarly, heterosis over check variety T-397 was found
significant and desirable in eleven crosses for number of capsules per plant, thirteen crosses for each
capsule diameter, seed yield per plant and oil content and in all the fifteen crosses for 1000-seed
weight.
Inbreeding depression in F2 generation showed that only one cross for days to 50% flowering,
three crosses for days to maturity, two crosses for plant height, three crosses for number of primary
branches per plant, eight crosses for number of capsules per plant, two crosses for number of seeds per
capsule, twelve crosses for capsule diameter, eleven crosses for seed yield per plant, ten crosses for
1000-seed weight and nine crosses for oil content revealed significant positive inbreeding depression.
For study of response to selection in early segregating generation in linseed in cross (Meera x
T-397) x Meera the highest mean value for days to 50% flowering was observed in BC1F3 generation
followed by BC1F2 base population and BC1F2 selected plant while for remaining characters the
highest mean value was seen for BC1F3 progeny population followed by selects and BC1F2 base
population. In both the populations i.e., BC1F2 and BC1F3 high values of PCV and GCV was found for
number of primary branches per plant, number of capsules per plant and seed yield per plant. High
heritability coupled with high genetic advance as per cent of mean was observed in BC1F2 and BC1F3
populations for number of capsules per plant and seed yield per plant. The traits such as plant height,
number of primary branches per plant, number of capsules per plant. number of seeds per capsule,
capsule diameter and 1000-seed weight showed positive and highly significant correlation with seed
yield per plant while path coefficient analysis concluded that in both the generations, direct selection
for characters such as number of capsules per plant, number of seeds per capsule, 1000-seed weight,
capsule diameter and number of primary branches per plant would be rewarding as they also showed
significant correlation with seed yield per plant.
At 20% selection intensity in cross (Meera x T-397) x Meera, all the characters exhibited
positive selection differential (S/rS) except days to 50% flowering. Standardized selection differential
was the highest for seed yield per plant, followed by number of capsules per plant, 1000-seed weight,
number of primary branches per plant, number of seeds per capsule and plant height. Days to 50%
flowering recorded negative value which is desired in case of earliness. The response to selection (R) was
found positive for all the characters. Maximum standardized selection response was obtained for number
of capsules per plant followed by days to maturity, seed yield per plant, days to 50% flowering, number
of primary branches per plant, plant height and 1000-seed weight. The realized heritability was found
high for all the characters, the highest being for days to 50% flowering followed by days to maturity,
plant height, number of capsules par plant, number of primary branches per plant, seed yield per plant
and 1000-seed weight indicating that the offspring of the selected parents differ from the original
population almost as much as the selected parents do. The predicted/expected selection differential (pS)
in BC1F2 was found highest in number of capsules per plant followed by plant height, days to maturity,
days to 50 % flowering, number of seeds per capsule, 1000-seed weight, number of primary branches per
plant and seed yield per plant. The predicted/expected selection response (pR) or (genetic advance) in
BC1F2 was seen highest for number of capsules per plant followed by plant height, days to maturity, days
to 50% flowering, 1000-seed weight, number of seeds per capsule, seed yield per plant and number of
primary branches per plant. The predicted or expected generalized selection response (pgR) in next
generation was maximum for seed yield per plant followed by days to 50 % flowering, number of
capsules per plant, plant height, 1000-seed weight, days to maturity, capsule diameter and number of
primary branches per plant. The predicted heritability in narrow sense (phNS) in BC1F2 generation was
found high (more than 60 %) for all the characters.
In cross (Shekhar x T-397) x Shekhar the highest mean value for days to 50 % flowering was
observed in BC1F3 generation followed by BC1F2 base population and BC1F2 selected plants while for
characters the highest mean value was seen for BC1F3 population followed by selects and BC1F2 base
population. Number of capsules per plant and seed yield per plant recorded high PCV and GCV values in
both the generations. In both the generations high heritability coupled with high genetic advance as per
cent of mean was observed for number of capsules per plant and seed yield per plant. The traits such as
days to maturity, plant height, number of primary branches per plant, number of capsules per plant,
number of seeds per capsule and 1000-seed weight showed positive and highly significant correlation
with seed yield per plant while path coefficient analysis showed that in BC1F2 generation maximum
positive direct effect was exerted on seed yield per plant by number of capsules per plant followed by
1000-seed weight, number of seeds per capsule, number of primary branches per plant, days to maturity
and plant height while in BC1F3 generation highest positive direct effects were revealed by number of
capsules per plant followed by capsules diameter, 1000-seed weight and days to maturity.
At 20% selection intensity in cross (Shekhar x T-397) x Shekhar, all the characters exhibited
positive selection differential (S/rS) except days to 50 % flowering. Standardized selection differential
was the highest for seed yield per plant, followed by number of capsules per plant, number of primary
branches per plant, 1000-seed weight, number of seeds per capsule, days to maturity and plant height.
Days to 50 % flowering recorded negative value which is desired in case of earliness. The response to
selection was found positive for all the characters. Maximum standardized selection response was
obtained for days to maturity, followed by number of capsules per plant, seed yield per plant, plant
height, number of primary branches per plant, 1000-seed weight, days to 50 % flowering and number
of seeds per capsule. The predicted/expected selection differential (pS) in BC1F2 was found highest in
number of capsules per plant followed by plant height, days to maturity, days to 50 % flowering,
number of seeds per capsule, 1000-seed weight, number of primary branches per plant and seed yield
per plant. The predicted/expected selection response (pR) or (genetic advance) in BC1F2 was seen
highest for number of capsules per plant followed by plant height, days to maturity, days to 50 %
flowering, 1000-seed weight, number of seeds per capsule, seed yield per plant and number of primary
branches per plant. The predicted or expected generalized selection response (pgR) in next generation
was maximum for days to 50 % flowering followed by seed yield per plant, 1000-seed weight, days to
maturity, number of capsules per plant, plant height, capsule diameter, number of primary branches per
plant and number of seeds per capsule. The predicted heritability in narrow sense (phNS) in BC1F2
generation was found high (more than 60 %) for all the characters except number of seeds per capsule.
Description
STUDIES ON GENETIC ARCHITECTURE AND RESPONSE OF SELECTION FOR YIELD AND YIELD ATTRIBUTING TRAITS IN LINSEED (Linum usitatissimum L.)
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