Estimation of induced variability in chillies
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Date
1985
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Department of agricultural botany , College of agriculture Vellayani, Trivandrum.
Abstract
The mutagenic effect of Co-gamma rays and
Ethylmethane sulphonate on three different chilli
varieties have bean studied in detail in generation
U3 ing two moderate doses of gamma rays <20 and 30 kR)
and two concentrations of ISMS (0.5 and 1*0 par cent)*
The presence and extent of chimeras and their relation
to induced variability was assessed by raising
branch-wise progenies in ^ generation* The experiment
was conducted during 1982-84 at the Department of Agricultural
Botany# College of Agriculture, Vellayani*
The generation was laid out in RBD and in splitplot
design with proper randomisation and replications*
The crop wa3 raised and maintained following the Package
of Practices recommended. The polygenic traits analysed
in a, generalisen include plant height, number of branches
per plant, fruit yield per plant and length and
weight of fruits. The data collected were statistically
analysed for proper interpretation of tho results
obtained.
It has been observed in almost all the polygenic
traits that the extent of variability created vary
depending on the genotypes, mutagen and their dosos and
character under observation. The mean values wer« found
to shift both in negative and positive directions to
control values• significant shift in mean values depending
on the type of branch category clearly demonstrates
that there exists the mechanism of diplontlc selection in
this particular crop variety# when exposed to mutagens.
But the extent of selection varies depending on the
mutagen and their doses and the genotypes concerned.
a significant negative shift in mean Value was noted
only in the case of fruit weight under both the concentrations
of EM3 and 20 kR gamma rays whereas a positive or
negative insignificant shift was noted in all other characters
under both the mutagens, when under EM3 and
in gansna rays showed a negative shift* positive shift in
mean value wes noted in majority of the cases for number
of branches per plant. Fruit length and weight and
number of seeds per fruit showed a negative shift in
majority of the cases analysed# but fruit number and yield
per plant showed a reverse trend. The shift in mean value
under the different branch categories varied depending
on the varieties# mutagens and their doses and also the
character under study.
The phenotypes were found toAdistributedboth in
negative and positive directions to control group in all
the characters analysed. The frequency distribution whether
negative or positive varied depending on the mutagen
and their doses# the genotypes and character under study.
In majority of tha cases the maximum frequencies
of positive variants under both the concentrations of
EMS and under 0.5 per cent for negative variants were
found to be in the early formad branches when it was
in the later ones is tha case of negative variants under
1.0 per cent EMS. in the case of gamma rays this general
trend was not observed* The data analysed clearly
demonstrate the existence of diplontic selection and
promises wide scope for positive selection response
either in negative or positive directions.
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Citation
T-391