ASSESSMENT OF PROTEIN, LYSINE AND STARCH CONTENTS IN GRAINS AND BIOCHEMICAL MARKERS ASSOCIATED WITH DROUGHT TOLERANCE IN SORGHUM GENOTYPES
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Date
2010
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Journal ISSN
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Publisher
MPKV,Rahuri
Abstract
The present investigation was undertaken to evaluate the ~
levels of crude protein, lysine and starch from the sorghum
grains of seven each of drought tolerant and susceptible
genotypes. In addition, the levels of proline, glycine betaine,
the activity of PSCS and soluble proteins were determined
from the leaves of these genotypes by imposing stress created
by polyethylene glycol-6000.
Among the drought tolerant genotypes under study, the
highest crude protein content of 9.63% was observed in the
grains of RSV -962, whereas among the drought susceptible
ones, the highest of 9.24% was observed in CSV-216.
Amongst the drought tolerant genotypes, the highest
lysine content of 2.19 g 16 g-1 N was observed in the grains of RSV-458 and among the susceptible ones, the highest of 2.17 g
16g-1 N was observed in SPV-504. As regards the starch content, a
drought tolerant genotype SPV-1546 recorded the highest of 77.40
per cent in the grains, whereas among the drought susceptible
ones, RSLG-1119 recorded the highest of 76.50 per cent.
The seedlings of 2-weeks-old sorghum genotypes were
evaluated for the accumulation of free proline, glycine betaine
and P5CS activity under control and PEG induced stress of
-0.5 MPa. On imposition of stress the mean proline
accumulation increased by 7 -folds in drought tolerant
genotypes as compared to a 3-folds increase in drought
susceptible ones. The highest proline content of 544.4 pmol g-I
fr.wt. was recorded in a drought tolerant genotype, RSLG-262.
The activity of the rate-limiting enzyme, P5CS in leaf materials
of drought tolerant genotypes demonstrated correspondingly
higher activity than the susceptible ones under PEG induced
stress. The mean fold increase of 2.44 in P5CS activity of leaf
materials was observed in drought tolerant genotypes,
whereas there was 1.44-fold in drought susceptible ones. The
maximum fold increase of 3.42 in P5CS activity was observed
in a drought tolerant genotype, Sel-3. As regards the
accumulation of glycine betaine, the mean fold increase of
3.71 was observed in drought tolerant genotypes as compared
to 1.57 -fold in leaf materials of a drought susceptible ones.