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COMBINING ABILITY ANALYSIS IN SESAME (Sesamum indicum L.)

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Title COMBINING ABILITY ANALYSIS IN SESAME (Sesamum indicum L.)
 
Creator VIJAYA DURGA, G
 
Contributor RATNA BABU, D
 
Subject planting, oilseeds, yields, biological phenomena, sowing, developmental stages, genetics, sesamum indicum, heterosis, additives
 
Description The present investigation was carried out during kharif 2011 and rabi 2011-12 at
Agricultural College Farm, Bapatla to study the variability, heritability, expected genetic
advance, combining ability, heterosis, character association and path coefficient analysis of
eight parents (five lines + three testers) and 15 F1s of sesamum for characters viz., days to
50% flowering, days to maturity, plant height (cm), number of primary branches per plant,
number of capsules per plant, number of seeds per capsule, 1000-seed weight (g), oil
content (%) and seed yield per plant (g).
Analysis of variance revealed significant differences among the genotypes for all
characters studied, indicating a high degree of variability in the material.
The estimates of heritability and genetic advance as per cent of mean were high for
the characters viz., number of primary branches per plant, number of seeds per capsule
number of capsules per plant, 1000-seed weight and seed yield per plant. High heritability
coupled with moderate genetic advance as per cent of mean was observed for plant height
and days to 50% flowering. While moderate heritability coupled with low genetic advance
as per cent of mean was observed for the characters viz., days to maturity and oil content.
The analysis of variance for combining ability revealed that lines, testers, lines vs
testers, crosses and Line x Tester effects had significant amount of variability within each
of them for majority of traits studied. The per cent contribution towards the total variance
was maximum due to the interaction of lines and testers for the traits days to maturity,
1000-seed weight, days to 50% flowering and oil content while contribution of lines alone
was maximum towards the total variance for number of capsules per plant, number of seeds
per capsule, seed yield per plant, plant height and number of primary branches per plant.
Out of the five lines tested in the present investigation, IS 355 followed by YLM 95
recorded significant general combining ability effects for majority of the characters studied.
Among the testers Gowri recorded good general combining ability effects for majority of
traits. Within the 15 Line x Tester combinations, KMR 42 x Madhavi followed by IS 355 x
RT 54, YLM 95 x Gowri and YLM 96 x Gowri recorded good specific combining ability
effects for important yield components. The gca effects of parents and sca effects of their
hybrid combinations indicated that the crosses with high sca effects were resulted due to
high x low, low x low and high x high gca combinations. Therefore it is worth including
some low general combiners also in hybridization programmes.
Further heterosis studies revealed that four Line x Tester combinations viz., IS 355 x
Gowri, KMR 42 x Madhavi, YLM 95 x Gowri and IS 355 x Madhavi registered significant
positive heterosis over both mid and better parents for seed yield per plant. Though the per
se performance of the parents are relatively low, the above combinations are highly
heterotic indicating better nicking ability of the lines and testers involved. Majority of lines
and testers which yielded heterotic hybrids registered good gca as well. With this it is
evident that lines with good gca though having less per se may also yield heterotic
combinations. This shows the importance of studying the combining ability effects of
different lines that are to be use either in heterosis breeding or in combination and
transgressive breeding.
The estimates of sca and gca variance also revealed the predominance of nonadditive
gene action in the inheritance of days days to 50% flowering, days to maturity, oil
content and 1000-seed weight while both additive and non-additive gene actions were
predominant for number of seeds per capsule, number of capsules per plant, plant height,
seed yield per plant and number of primary branches per plant. These gene actions were
further confirmed by the ratios of gca variance to total genetic variance and the estimates of
narrow sense heritability.
The traits number of capsules per plant, number of seeds per capsule, number of
primary branches per plant and plant height were found to possess significant positive
association with seed yield per plant at both genotypic and phenotypic levels. While path
analysis studies revealed that number of capsules per plant showed true relationship by
establishing significant positive association and high positive direct effect on seed yield per
plant followed by number of seeds per capsule, number of primary branches per plant and
plant height. From this it can be inferred that simultaneous improvement in seed yield per
plant is possible through manifestation of number of capsules per plant, number of seeds
per capsule and number of primary branches per plant.
It can be concluded that out of the five lines tested for their combining ability the
line IS 355 exhibited significant gca effects in desirable direction for the traits number of
seeds per capsule, number of capsules per plant, plant height, seed yield per plant and
number of primary branches per plant while another line YLM 95 also recorded good gca
effects in desirable direction for number of capsules per plant, number of seeds per capsule,
seed yield per plant, number of primary branches per plant and 1000-seed weight. These
two lines also resulted in heterotic hybrids when test crossed with different testers used in
the study. Therefore, one can utilize the above two lines either in heterosis breeding or in
transgressive breeding for the improvement of respective characters in which they
registered good general combining ability effects.
 
Date 2016-06-22T11:49:06Z
2016-06-22T11:49:06Z
2012
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67675
 
Language en
 
Relation D9405;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY