GENETIC DIVERGENCE FOR POD QUALITY, YIELD AND YIELD ATTRIBUTES IN DOLICHOS BEAN (Dolichos lablab L. var. typicus Prain) GERMPLASM
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Date
2017-07-20
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College of Horticulture, Rajendranagar, HYD-30
Abstract
A field experiment entitled “Genetic divergence for pod quality, yield and yield
attributes in dolichos bean (Dolichos lablab L.var. typicus Prain) germplasm” was carried
out to study genetic divergence, genetic variability parameters and yield component analysis
through correlation and path analysis. Thirty two genotypes of dolichos bean germplasm
along with three checks were evaluated in Randomized Block Design with two replications,
during August, 2016 to March, 2017 at Vegetable Research Station, ARI, Rajendranagar,
Hyderabad with the objective to identify divergent genotypes and use as donor parents in
hybridization programmes.
The analysis of variance revealed significant differences between genotypes
indicating presence of sufficient amount of variability in all the 19 characters studied. Wide
range of variability was observed for pod yield per plant (46487.040), vine length
(15234.210) and number of pods per plant (2379.014) indicating the scope for selection of
initial breeding material for further improvement.
On the basis of mean performance, genotype IC-546387 was found superior for pod
yield per plant (805.23g), more number of pods per plant (175.66), vine length (462.17cm)
and pod attributes like medium pod width (1.29cm) followed by IC-427428, which was
found significantly superior over the check variety RND-1 with regard to pod yield per plant
(667.07g), number of pods per plant (92.76), for earliness in days to first flowering (86.00),
days to first pod harvest (104.50), and pod attributes like pod length (12.61cm), pod width
(2.03cm) and protein content (24.76%).
Mahalanobis D2 statistical analysis, revealed that pod yield per plant, fiber and protein
content, number of pods per plant, days to last pod harvest, pod length, 100 dry seed weight,
vine length, number of seeds per pod, seed length, 100 fresh seed weight and pod weight
contributed towards genetic divergence and 35 genotypes were partitioned into six clusters
based on Tocher‟s method. Maximum divergence was observed between cluster III and VI
(D2=1780.19), while minimum was observed between cluster II and cluster IV (333.46). The
maximum intra cluster distance was shown by cluster IV (D2=249.64).
The clusters showing high genetic divergence could be effectively utilized in
heterosis breeding programme. If a breeding programme is used at improving protein
content, cluster II (PSRJ-13039) showing maximum protein content (25.09%) can be utilized
in breeding programme.
GA as per cent of mean, GCV and PCV values were on par with each other for most
of the characters which indicated that the influence of the environment on the trait (s) was
very negligible. The recorded values were not influenced by the environment. It is a true
reflection of the homeostasis effect or buffer reaction of the gene. Thus, the true reflection of
the trait is exhibited.
A true agreement with the GCV and PCV values in the present investigation for the
19 characters was noticed, indicating additive genetic variance governing the high
heritability with high genetic advance as per cent of mean. Thus, a breeder can employ a
simple selection process which will be a rewarding one to improve the yield attributing
characters and protein content. High heritability coupled with moderate genetic advance as
percent of mean was observed for days to 50% flowering, days to first pod harvest and days
to pod maturity. Moderate heritability coupled with moderate genetic advance as per cent of
mean observed for number of primary branches per plant indicates non additive action
controlling the traits.
From correlation studies, it was observed that pod yield per plant has exhibited highly
significant and positive association with vine length (0.511), number of pods per plant
(0.494), pod weight (0.485), seed breadth (0.389), seed length (0.349), 100 dry seed weight
(0.325), primary branches per plant (0.291), days to 50 percent flowering (0.254), days to
first flowering (0.244) and pod length (0.240).
Path analysis revealed that maximum positive direct effect on pod yield per plant was
exhibited through pod weight (0.440) followed by protein content (0.235). Positive direct
effect of primary branches per plant (0.229) on pod yield per plant was moderate.
Dolichos bean genotypes exhibited high variability for all qualitative traits viz., plant
growth characters, leaf characters, flower characters, pod characters and seed characters.
Therefore, it is emphasized to lay attention on the traits viz., number of pods per plant, pod
weight, days to last pod harvest, pod length, protein content and less fiber content in crop
improvement programme of dolichos bean in future.
Considering mean performance, heritability, variability, genetic advance as percent of
mean and correlation analysis, two genotypes i.e. IC-427428 and IC-546387 were identified
as best genotypes compared to check. Hence, these may be utilized for multilocation trials
for further yield exploitations as they are attributed with high mean performance with many
useful genes for majority of traits studied. They can also used in further breeding
programmes and may be released as a variety after multi location trails.
Description
The analysis of variance revealed significant differences between genotypes
indicating presence of sufficient amount of variability in all the 19 characters studied. Wide
range of variability was observed for pod yield per plant (46487.040), vine length
(15234.210) and number of pods per plant (2379.014) indicating the scope for selection of
initial breeding material for further improvement.
Keywords
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Citation
Sri Konda Laxman Telangana State Horticultural University, Rajendranagar, Hyderabad-30