Callus development, plant regeneration and in vitro selection for drought tolerant cell lines of wheat [Triticum aestivum l.]
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Date
2007
Authors
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Publisher
CCSHAU
Abstract
Wheat (Triticum aestivum L.) is world’s leading cereal grain and also the
most important food crop. In recent years a considerable improvement has
been made in wheat using in vitro and in vivo techniques. The present study
was planned to study the callus development and plant regeneration
potential of wheat and to screen ten wheat genotypes viz., WH-147, WH-711,
PBW-343, WH-542, HD-2687, WH-533, PBW-502, WH-1025, WH-773 and
C-306 for drought tolerance using in vitro and in vivo techniques. The mature
embryos of five wheat genotypes (WH-147, WH-711, PBW-343, WH-542 and
WH-533) were cultured on MS1 (MS + 2.0% 2,4-D), MS2 (MS + 2.5% 2,4-D)
and MS3 (MS + 3.0% 2,4-D) media for callus induction and regeneration. The
calli were screened for drought tolerance by culturing them on MS2 media
supplemented
with various concentrations of PEG (6000 MW) viz., 7.5%, 10.0%, 12.5%,
15.0% and 17.5%. For in vivo drought screening, the seeds of wheat
genotypes were sown in small plastic pots and the drought stress was
produced by using different concentrations of PEG and the seed germination,
seedling length, moisture content were measured. Based on these, vigour
index and stress index were calculated. The results of the study revealed that
the MS3 medium was superior to MS1 and MS2 medium for callus induction.
The genotypic variation was present for callus induction and the mean callus
induction was found the highest in WH-711 (83.85%) and the lowest in
PBW-343 (65.66%). Callus regeneration was the highest in genotype
PBW-343 (89.58%, from the calli developed on MS3 medium). Similarly, the
number of shoots regenerated /callus was higher in WH-533 (9-10, from the
calli developed on MS3 medium) and the lowest in WH-147 (5, from the calli
developed on MS1 medium). Average seed germination was found the highest
in WH-533 and WH-147 (80.00%) but at maximum stress level (17.5% PEG),
the germination of PBW-502 (56.67%) was the highest. Moisture content of
WH-147 was found the highest (89.44%). When the genotypes were compared
for the callus growth percentage and stress index, the genotypes WH-533,
WH-147, HD-2687 and C-306 were found better than the other genotypes
under study.
Description
Keywords
Drought stress, PEG, Seedling, Wheat, Callus, Seed Germination, Moisture content, Vigour index