INFLUENCE OF ACCELERATED AGING AND GA3 PRIMING ON SEED QUALITY OF SORGHUM
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Date
2021-09-03
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Abstract
The present investigation was carried out in the Department of Seed Science
and Technology, Advanced Post Graduate Centre, Lam, during 2019-20 to assess the
influence of accelerated aging on physiological and biochemical parameters of
sorghum seed also to study the effect of priming with gibberellic acid on quality of
accelerated aged seed of sorghum, variety NTJ-5 and to predict the storage potential
of sorghum seed using accelerated aging test.
Initially seed of sorghum variety, NTJ-5 was subjected to accelerated aging for
24, 48, 72 and 96 h. The physiological and biochemical parameters of accelerated
aged seeds were tested along with control (unaged seed). The accelerated aging
caused highly significant decline in all the seed quality parameters viz., germination,
seedling length, seedling vigour index, field emergence, total soluble sugars and
peroxidase (POX) activity. Moisture content, electrical conductivity (EC) of seed
leachates, proline content, hydrogen peroxide (H2O2) and malondialdehyde (MDA)
content showed a highly significant increase with increase in the duration of
accelerated aging. Maximum per cent decline in germination (39.55%), seedling
length (24.79%) seedling vigour index (54.63%), field emergence (37.18%), total
soluble sugars (30.06%) and peroxidase (POX) activity (45.02%) over the control was
observed with 96 h of accelerated aging.
Correlation studies showed a highly significant positive correlation among all
the physiological parameters except moisture content and EC of seed leachates which
showed highly significant negative association with the remaining characters. Total
soluble sugars and POX activity exhibited a significant positive association and
proline, H2O2 and MDA content had a significant negative correlation with all the
physiological parameters under study except EC of seed leachates.
The accelerated aged seed was subjected to hormonal priming with GA3 50
ppm for various durations (3, 6, 9 and 12 h) along with control to standardize the best
duration of priming. The seed quality traits were studied by performing standard
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germination test by between paper method. Among different durations, highest
germination (%), seedling length (cm) and seedling vigor index were recorded with 9
hours duration and beyond that the seed quality declined gradually upto 12 hours.
Based on standardization results the aged and unaged seed of sorghum was
subjected to seed priming with GA3 50 ppm for 9 hours and shade dried to reach safe
moisture content. The invigorated aged seed along with untreated aged and unaged
seed was used for assessing physiological and biochemical characters. Results
revealed that accelerated aging caused a highly significant reduction in all the
physiological parameters except EC of seed leachates and showed a highly significant
increment in all the biochemical parameters under study except total soluble sugars
and POX activity. Hormonal priming with GA3 50 ppm showed a highly significant
improvement in seed quality and biochemical parameters. The interaction effect
between accelerated aging and hormonal priming with GA3 showed a significant
impact on all the physiological and biochemical parameters except germination and
field emergence.
Correlation studies showed a highly significant positive correlation among all
the physiological parameters except EC of seed leachates which exhibited significant
negative association with the remaining characters. Total soluble sugars showed a
positive association and POX activity had a significant positive correlation with all
the physiological parameters except EC of seed leachates. Proline content exhibited a
significant negative association whereas H2O2 and MDA contents showed a highly
significant negative association with all the physiological parameters under study
except EC of seed leachates.
The seed samples with different levels of germination and seedling vigour thus
obtained by accelerated aging along with the control were kept for storage in cloth
bag under ambient conditions. The physiological parameters were tested at monthly
interval, while biochemical characters were assessed at bimonthly intervals. The
physiological parameters, total soluble sugars and POX activity decreased
significantly and the EC of seed leachates, proline, H2O2 and MDA content showed a
highly significant increase due to accelerated aging and period of storage. The results
indicated that the germination recorded at 24 h of accelerated aging was almost
equivalent to normal (unaged) seed stored for 4 months. From the results it can be
found that accelerated aged exhibited lesser storability compared to unaged seed.
Correlation studies of biochemical characters with germination, seedling quality
parameters and EC of seed leachates of accelerated aged seed of sorghum during
storage revealed that total soluble sugars and POX activity showed a positive
correlation and proline, H2O2 and MDA content exhibited a negative correlation with
all the physiological parameters under study except EC of seed leachates.
The present study proved that hormonal priming with GA3 50 ppm
significantly improved the quality of accelerated aged seed of sorghum. Accelerated
aging test can be used to predict the storability of sorghum seed.
Description
INFLUENCE OF ACCELERATED
AGING AND GA3 PRIMING ON SEED
QUALITY OF SORGHUM