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Wheat Information
Service
Number 72: 14-17 (1991)
Seedling
studies on dwarf mutants of tall varieties of rainfed
wheat
R. Kumar, H. C. S. Negi* and K. Kant*
Division of Genetics Indian Agricultural Research Institute New
Delhi-110012, India
Summary
The study on the seedlings of three rainfed wheat varieties and
their dwarf mutants indicated that in spite of a positive correlation
between the coleoptile length and plant height, it is possible to
select genotypes having long coleoptile and well developed root
system with dwarf plant type suitable for sowing under rainfed
conditions. The study also revealed that coleoptile length is not
under pleiotropic control of dwarfing gene. Embryonic root number and
length are two independent characters.
Introduction
Traditionally tall wheat cultivars, matchless for quality
characteristics have remained unexploited for intensive cultivation
in agronomically rich environments, obviously due to tendency for
lodging. However, under rainfed agriculture they find no substitute
from dwarf category. Under moisture stress conditions, seeds are
deeply placed in the moist zone to insure maximum germination. In
deep sowings recently-developed dwarf wheat varieties have poor
seedling emergence due to short coleoptile length, which is known to
show significant positive correlation with the plant height (Allan et
al 1961). There is thus, a need for identification/induction of new
and effective culm shortening genes for non-lodging with standard
coleoptile length for better field emergence. Good root system is
another important characteristic of rainfed wheats (Rozentreter 1950;
Vedrob 1971). Rajendra Kumar (1984) induced dwarfness through
experimental mutagenesis in three tall rainfed wheat cultivars. The
present attempt is to evaluate the seedling characters of these dwarf
mutants to assess their suitability under rainfed conditions.
Materials and Methods
The experimental material for present study comprised of three
rainfed wheat varieties C 306, K 65 and NI 5439 and their ten dwarf
mutants in M5 generation developed through experimental
mutagenesis. Ten dwarf mutants along with three parental lines were
sown in three replications in random block design at IARI
Experimental Farm, New Delhi. The average height of ten plants per
replication was recorded from ground surface to the tallest tiller's
earhead excluding awns at maturity. One thousand seeds were counted
from the cleaned seed and the weight was recorded for each plot.
Twenty seeds/replication of each line were kept for germination in
template stands in a seed germinator at 20C
under moist
conditions for seven days as per ISTA rules (Anonymos 1976). The
Laboratory experiment was conducted in three replications.
Observations on coleoptile length, embryonic root number and maximum
root length were recorded on ten seedlings per replication. Random
block design analysis were done for calculating critical difference
(C. D.) for each character.
Central Seed Testing
Laboratory, Indian Agricultural Research Institute, New Delhi-110
012.
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