Genetic variability among the accessions of Sesbania species for morphological and biochemical markers
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Date
2005
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CCSHAU
Abstract
Field experiment and isozymic analysis on 40 accessions of Sesbania were carried out
with the objectives: (i) to estimate variability among accessions of Sesbania using various
isozymes and morphological markers and (ii) to establish relationship among accessions using
these parameters. The accessions were grown in randomized block design with three replications.
The observations were recorded on 15 variables viz., plant height (at 20 and 60 days after
sowing, and at maturity), green biomass, dry weight, number of root nodules, fresh weight of
root nodules, leaf length, leaves per plant, leaflets per leaf, number of pods per plant , pod length,
number of seeds per pod, 100-seed weight and seed yield per plant.
Significant genotypic differences were observed for all the 15 morphological characters.
Accession EC 493668 (T21) from Australia was identified for its direct exploitation as a cultivar.
Seed yield showed positive correlation with number of pods, number of seeds per pod, pod
length, leaf length and plant height at maturity. Weight of root nodules, number of pods and pod
length showed high positive direct and indirect effects contribution towards their correlation with
seed yield. Seed yield and its components showed medium to high heritability and genetic
advance.
UPGMA method with Euclidean distances based on agromorphological traits grouped
accessions into seven clusters. Accessions T3 from cluster 1 and T24 from cluster 7 were
recommended for hybridization programme for improvement of grain yield. Cluster 7 showed
high inter cluster distance from clusters namely cluster 2, 3 and 4.
The accessions were fingerprinted for 6 isozyme systems (acid phosphatase, amylase,
catalase, glutamate dehydrogenase, peroxidase and malate dehydrogenase) and grouped the
accessions into 11 clusters. Malate dehydrogenase and glutamate dehydrogenase exhibited
maximum unique isozymic patterns i.e. 38 and 31, respectively followed by acid phosphatase,
amylase, peroxidase and catalase. None of the enzyme system could alone distinguish all the
accessions individually, however, a combination of any of the two enzyme systems may be used
to distinguish all 40 accessions uniquely.
Majority of accessions of S. rostrata were grouped together in one cluster in both
agromorphological and isozymic data analysis. Both analyses indicated that geographical
diversity is important but not the sole factor determining the genetic diversity.
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