Genetic divergence studies in okra (abelmoschus esculentus (l.) Moench.)
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Date
2017-07-05
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Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani
Abstract
The present investigation was undertaken to estimate the genetic
divergence in okra and to carry out yield component analysis through
correlation and path analysis. Twenty genotypes were sown in a randomized
block design with two replications, during Kharif 2016-2017 at Horticulture
Research Station, College of agriculture, VNMKV, Parbhani, Maharashtra. The
objective of the experiment was to identify divergent genotypes to use as donor
parents in hybridization programmes.
The D2 analysis for eighteen characters partitioned the twenty genotypes
into five clusters. The maximum genetic divergence was observed between
cluster III and V followed by between clusters I and V. The maximum intra
cluster distance was shown by cluster IL The characters number of branches
per plant, number of fruits per plant, total number of pickings, fruit weight,
fruit length and fruit yield per plant contributed greatly towards diversity. The
clusters showing high genetic divergence could be effectively utilized in
heterosis breeding programme. If a breeding programme is used at improving
growth attributes like plant height, then cluster III showing maximum plant
height can be utilized in breeding programme. Therefore, a plant breeder may
keep in mind the above aspects to obtain superior hybrids and good
recombinants.
The analysis of variance revealed significant difference for eighteen
characters studied suggesting considerable amount of variability exists among
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the genotypes. Wide range of variability was observed for plant height, number
of seeds per fruit, iodine content, and fruit yield per plant indicating the scope
for selection of suitable initial breeding material for further improvement.
In a true agreement with the GCV and PCV values in the present
investigation for most of the characters was noticed, indicating additive genetic
variance governing the high heritability (>60%) with high genetic advance as
per cent of mean was high (>20%) for plant height, number of branches, days
to first flowering, days to 50% flowering, days to first harvest, average fruit
weight, number of fruits per plant, number of seeds per fruit, number of
pickings, 100 seed weight, crude fibre content, iodine content, iron content and
fruit yield per plant. Hence there could be exercised for improvement through
selection.
From correlation studies it was observed that fruit yield per plant has
exhibited highly positive and significant association with plant height, number
of branches per plant, inter nodal length, days to last harvest, fruit length, fruit
girth, fruit weight, number of fruits per plant, number of seeds per fruit, 100
seed weight and number of pickings, crude fibre content, iron content and
iodine content. Therefore, it is emphasized to lay attention on these traits in
crop improvement programme of okra in future.
The results on path analysis indicated that the characters which
exhibited maximum positive direct effect on fruit yield per plant and positive
associations like Plant height, Number of branches per plant, inter nodal length,
days to first flowering, days to first harvest, fruit length, fruit girth, average
fruit weight, number of seeds per fruit, 100 seeds weight, total number of
picking, crude fibre content, iodine content and iron content would be more
effective to bring improvement of yield and to evolve superior high yielding
genotypes in okra.
On the basis of mean performance of the genotypes among traits
studied, IC-43743 from cluster III, PBNOK-2 from cluster V and IC-22237
from cluster IL were found to be best in almost all the attributes i.e. , growth,
earliness, fruit traits, and yield. Hence, for exploitation of fruit quality four
genotypes i.e., IC-10533, PBNOK-2, PBNOK-5 and EC-755648 were found to
be best for qualitative characters. So, these genotypes were considered the best
genotypes and would be used as parental source in future breeding
programmes.