HETEROSIS AND COMBINING ABILITY IN OKRA [Abelmoschus esculentus (L.) Moench] 2937
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Date
2019-08
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JAU, JUNAGADH
Abstract
The present investigation entitled “heterosis and combining ability in okra
[Abelmoschus esculentus (L.) Moench]” was undertaken at the Vegetable Research
Station, Junagadh Agricultural University, Junagadh during summer 2018. The
experimental material comprised of 6 lines viz., GO-2, VRO-6, JOL-2K-19, HRB-55,
HRB-108-2 and AOL-08-5; five testers namely; AOL-13-133, AOL-13-73, Kashi
Kranti, EC-169513 and IC-90107; their 30 hybrids derived from line x tester mating
and one check variety, GJOH-4. These 42 genotypes were evaluated in a Randomized
Block Design with three replications. Observations were recorded on days to 50%
flowering, days to first picking, plant height, number of branches per plant, number of
nodes per plant, fruit girth, fruit length, internodal length, number of fruits per plant
and fruit yield per plant.
Analysis of variance revealed significant variations among the genotypes,
parents and hybrids for all the ten traits. The mean squares due to parents vs. hybrid
were significant for all the characters under investigation except days to 50%
flowering and fruit girth.
The magnitude of standard heterosis in the positive direction was high for
plant height and number of branches; medium for number of fruits per plant and yield
per plant and low for number of nodes per plant and fruit length. Similarly, the
magnitude of standard heterosis in the negative direction was high for days to 50%
flowering and medium for internodal length and low for days to first picking and fruit
girth. The three crosses viz., JOL-2K-19 x AOL-13-73, JOL-2K-19 x EC-169513 and
GO-2 x EC-169513 manifested significant and desirable heterobeltiosis and standard
heterosis.
The analysis of variance for combining ability revealed that mean squares due
to lines x testers were found highly significant for all the traits under study except
fruit girth, it was significant. Whereas, variance due to lines and testers were found
also significant for all the traits (except the line for fruit girth and tester for days to
first picking, number of nodes per plant and fruit length). The magnitude of SCA
variance was higher than GCA variance for all the traits indicated preponderance of
non-additive gene action in the expression of yield and yield attributing traits except
plant height.Abstract
The results on gca effects of the parents indicated that none of the parents was
found to be good general combiner simultaneously for all the characters. The
estimates of gca effects of parents revealed that IC-90107 and HRB-55 for days to
50% flowering, HRB-55 and EC-169513 for days to first picking, GO-2, EC-169513
and AOL-08-5 for plant height, GO-2, JOL-2K-19, AOL-08-5, AOL-13-133 and
AOL-13-73 for number of branches per plant, AOL-08-5 and IC-90107 for number of
nodes per plant, HRB-108-2, AOL-08-5 and EC-169513 for internodal length,
JOL-2K-19, AOL-08-5 and EC-169513 for number of fruits per plant, GO-2 and
VRO-6 for fruit length, JOL-09-07, AOL-13-73 for fruit girth, EC-169513, GO-2 and
JOL-2K-19 for fruit yield per plant were found good general combiners for respective
traits.
As regard to specific combining ability effects, the best cross combination
were JOL-2K-19 x AOL-13-133 for days to 50% flowering; HRB-108-2 x
AOL-13-133 for days to picking; HRB-55 x AOL-13-133 for plant height; VRO-6 x
EC-169513 for number of branches per plant; JOL-2K-19 x AOL-13-73 for number
of nodes per plant and number of fruit per plant; AOL-08-5 x AOL-13-73 for
internodal length; AOL-08-5 x Kashi Kranti for fruit length, JOL-2K-19 x
AOL-13-73 for fruit yield per plant and no one cross significant and best for fruit
girth.
On the basis of per se performance and heterosis over standard check,
JOL-2K-19 x AOL-13-73, JOL-2K-19 x EC-169513 and GO-2 x EC-169513 were
found to be the best cross combinations for fruit yield and some yield attributing
traits. The crosses JOL-2K-19 x AOL-13-73 involved good x average general
combiner, JOL-2K-19 x EC-169513 good x good and cross, GO-2 x EC-169513 good
x good general combiner. This was also true for some yield components. Such crosses
appeared to be suitable for exploitation in practical plant breeding.
From the present findings, it can be concluded that sufficient variability was
present in the materials studied for yield and its components. The non-additive gene
action was observed in the inheritance of fruit yield and other yield associated traits
except plant height. This suggested that heterosis breeding would be more suitable for
the improvement of these traits in okra.