INDUCED MUTAGENESIS THROUGH GAMMA RAYS AND EMS IN COWPEA [Vigna unguiculata (L.) Walp] 2954
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Date
2019-09
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JAU, JUNAGADH
Abstract
The present investigation entitled “Induced mutagenesis through gamma rays
and EMS in cowpea [Vigna unguiculata (L.) Walp]” was under taken to find out the
amount and types of variability developed and their impact on association between
different characters. The seeds of GC-5 were exposed to 100, 200, 225, 250 275 300
and 400Gy of gamma rays at Bhabha Atomic Research Center, Trombay, Mumbai
and another lot of seeds treated with 0.25% EMS. Treated seeds were considered as
M1 generation for laboratory and field condition.
Field studies was carried out for M1 and M2 generation in Randomized Block
Design and Complete Family Block Design, respectively with two replications at
Pulses Research Station, Junagadh Agricultural University, Junagadh during summer
2018 and kharif 2018, respectively .
In M1 generation (Laboratory) observations were recorded for germination per
cent, radical length (cm), plumule length, root fresh weight, shoot fresh weight, root
dry weight, shoot dry weight, seed vigour index (mass) and seed vigour index
(length). Field study of M1 generation carried out in all mutagen treatments for the
study of germination per cent, plant height, number of primary branches per plant,
number of clusters per plant, number of pods per plant and seed yield per plant. All
characters were significant except germination per cent in M1 generation field
condition.
For raising M2 generation, seeds of 20 superior plants were taken from M1
generation. In M2 generation, observations were recorded for days to flowering, days
to maturity, plant height, number of primary branches per plant, number of clusters
per plant, number of pods per cluster, number of pods per plant, pod length, number
of seeds per pod, seed yield per plant and test weight.Analysis of variance revealed significant differences among the mutagenic
family for all characters except number of primary branches per plant. Significant
existence of variation was observed for progenies within family in M2 generation, for
days to flowering, days to maturity, plant height, number of clusters per plant, number
of pods per cluster, number of pods per plant, pod length, number of seeds per pod,
seed yield per plant and test weight.
PCV and GCV high for number of seeds per pod and seed yield per plant,
while all other characters had moderate phenotypic and genotypic coefficient of
variation except days to flowering, days to maturity and test weight. High heritability
and high genetic advance found in plant height, number of primary branches per
plant, number of clusters per plant, number of pods per cluster, number of pods per
plant, seed yield per plant. High heritability coupled with high genetic advance were
observed for this trait, which may be attributed to the preponderance of additive gene
action and selection pressure could profitably be applied.
The seed yield per plant showed positive and highly significant correlation
with number of clusters per plant and number of pods per plant, plant height at both
genotypic and phenotypic levels. The seed yield per plant had negative and non
significant correlation with days to flowering, days to maturity, number of primary
branches per plant and test weight. Positive and significant correlation found between
seed yield per plant and pods per plant in mutagen treatments 0.25% EMS and 0.25%
EMS + 225Gy gamma rays.
It is concluded from present investigation that induction of genetic variability
through mutagenic treatments is possible in cowpea and as supplement to
conventional breeding methods. Mutagenic treatments increase the genetic variability
which can be utilized for selection and improvement of cowpea. In M2 generation
significant and positive as well as significant and negative shift of mean performance
were observed in most of characters except days to flowering and days to maturity as
compared to control treatments. High genotypic and phenotypic coefficient of
variation were observed for number of seeds per pod and seed yield per plant, while
moderate phenotypic and genotypic coefficient of variation were observed for plant
height, number of primary branches per plant, number of clusters per plant, number of
pods per cluster, number of pods per plant and pod length. Highest range for seed
yield per plant was observed for treatment T2 (200Gy gamma rays) and T9
(0.25% EMS + 100Gy gamma rays) where in T9 exhibited highest GCV, heritability
coupled with genetic advance and so, progenies of T9 should given more weightage
during selection to identify high yielding varients.