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Effects of Different Drying Methods and Rate of Drying on Quality and Storability of Sorghum (Sorghum bicolor (L.) Moench) and Pearl Millet (Pennisetum glaucum L.) R. Br.) Seeds

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Title Effects of Different Drying Methods and Rate of Drying on Quality and Storability of Sorghum (Sorghum bicolor (L.) Moench) and Pearl Millet (Pennisetum glaucum L.) R. Br.) Seeds
M.Sc.
 
Creator MANISH KUMAR VIJAY
 
Contributor Sushil Pandey
 
Subject maize, intercropping, legumes, yields, cowpeas, crops, biological phenomena, nitrogen, planting, proteins
 
Description T-8838
oisture content (mc) of seeds is a key component that determines the storage potential
of germplasm conserved in seed gene banks. The genotypes of sorghum and pearl millet were
dried using silica gel, saturated salt of lithium chloride, conc. sulphuric acid and dryer
(conventional method used to dry seeds for conservation in seed gene banks at 15oC and 15%
RH) to obtain the moisture content up to 6%. Among the drying methods, the seed desiccated
using acid and silica gel attained a moisture content of 6 + 0.2% in 8 to 12 days duration in
different genotypes, whereas the seeds dried using lithium chloride and seed dryer attained the
similar moisture content after 19 to 24 days. Seeds were stored up to 6 months under ambient
conditions. Among the different seed quality parameters studied, germination, vigour, total
protein content, dehydrogenase, amylase, superoxide dismutase (SOD) and peroxidase showed
decline whereas water soluble sugar (WSS), electrical conductivity (EC) showed higher value in
different genotypes, irrespective of the drying methods. Although drying by seed dryer and
lithium chloride, the rate of drying was slow but was most conducive for maintaining the seed
quality and storage potential. In case of acid and silica gel drying, rate of drying was quick, but
acid drying had pronounced harmful effects on seed quality during storage whereas silica gel
drying was found to be effective and quicker as compared to seed dryer and maintained the high
seed quality which was comparable with slow drying methods using seed dryer and lithium
chloride, over the storage period.
The longevity of seed depends on the amount of water it contains and on the temperature
under which it is stored. In general, lower the moisture content, longer the seed longevity.
Sorghum and pearl millet are orthodox and tolerate drying to low moisture content, but there is
a need to determine the optimum moisture content to prolong the seed storage without affecting
seed viability. The sorghum and pearl millet genotypes were dried using silica gel and to obtain
about 7%, 5% and 3% mc and were stored under ambient and MTS (15oC and 15% RH)
conditions for six months. In case of sorghum, the mc of 7% and 5% gave higher values for
germination and associated seed quality parameters studied as compared to 3% mc, whereas in
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case of pearl millet, the mc of 5% and 3% gave higher values for seed quality parameters as
compared to 7% mc, irrespective storage conditions. Biochemical parameters such as EC, WSS
which are negatively correlated with seed quality, showed significantly higher values in control
followed by seeds stored with 3% mc in sorghum and 7% in pearl millet. Higher values of SOD,
POX, amylase, dehydrogenase and protein content, which are positively correlated with seed
quality, was observed in seeds stored with 5% and 7% mc in sorghum while 3% in pearl millet
over the control after six months of storage. The study reveals that optimum moisture content
for extending seed storability and to ensure maximum viability is between 5-7% in sorghum,
while 3-5% in case of pearl millet.
The effect of different drying methods on seed quality after aging was studied using
molecular markers such as SSR, ISSR and SCoT. SSR primer study showed monomorphism,
irrespective of moisture contents, drying methods and genotype studied. However
polymorphism was recorded in SCoT and ISSR primers in sorghum genotypes, which indicated
that the deleterious effects of ultra-drying and acid drying after accelerated aging. SDS-PAGE
protein profile also showed maximum number of bands in 5% and 7% mc in sorghum while 3%
and 5% mc in pearl millet after accelerated aging as compared to control.
Micro-morphological study using scanning electron microscope (SEM) clearly showed
the impact of acid drying and ultra-drying on seed ultra-structure. The destruction of seed
surface and endospermic starch granules in acid dried and accelerated aged seeds of sorghum
and pearl millet was conspicuous. Similar impact was also observed in the ultra-dried seeds of
sorghum while no change was recorded in pearl millet. Therefore ultra-drying was found to be
suitable for extending the seed storage life in pearl millet.
The present study on sorghum and pearl millet seeds using different parameters, namely,
physical, physiological, biochemical, molecular and micro-molecular parameters, reveals that
pearl millet seeds can be dried upto 3% mc without affecting the structural integrity and storage
potential, whereas, in case of sorghum, safe mc for storage is 5%, as below this, the structural
integrity and storage potential is adversely affected.
 
Date 2016-06-22T12:08:16Z
2016-06-22T12:08:16Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67696
 
Format application/pdf
 
Publisher IARI,Division of Germplasm Conservation