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Wheat Information
Service
Number 75: 46-53 (1992)
Genetic
variability in grain yield and its component characters and their
association under salt stress conditions in tissue culture lines of
bread wheat (Triticum aestivum L. em. Thell)
K. N. Singh and Ravish Chatrath
Central Soil Salinity Research Institute, Karnal 132001,
(Haryana), India.
Summary
An experiment was conducted to study genetic variability and
associations among different characters under saline and sodic stress
conditions in 24 wheat lines developed through tissue culture. The
study showed that the means of all the characters declined under both
types of stress conditions, the decrease being maximum under sodic
conditions. There was reduction in genetic variability, genetic
advance and heritability for important character like grain yield per
plant. The associations among characters indicated that, under saline
conditions, number of ear-bearing tillers per plant, and under sodic
conditions, grain weight, number of grains per ear, number of
ear-bearing tillers per plant, plant height and number of spikelets
per ear were important contributors toward grain yield.
Introduction
The magnitude of heritable variability in any genetic stock has a
close bearing on the success of selection programs. Since there is no
such information on wheat tissue culture lines under stress
conditions, an experiment was conducted under edaphic stress
conditions to study genetic variability in grain yield and its
component characters and their correlations in bread wheat lines
which were developed through tissue culture. Path coefficient
analysis was also made to determine the contribution of each
character on grain yield under normal, saline and sodic stress
conditions.
Materials and methods
The experimental materials consisted of 24 bread wheat lines
selected from 137 lines originally obtained in 1989-90 from CIMMYT,
Mexico, which were developed through tissue culture technique. The
materials were sown with four replications, each in normal soil,
sodic soil
(pH2 9.3) and under saline water irrigation conditions
(ECiw 20 dSm-1). The experiment was laid out in
a split plot design, with three edaphic environments in the four
replicated main plots and 24 tissue culture lines in the sub plots.
Each line was sown in one row of 80 cm in length and with a
row-to-row distance of 23 cm. Randomly taken 5 representative plants
from each entry in each replication provided the material for the
evaluation of seven characters, viz., plant height, number of
ear-bearing tillers per plant, main ear length, number of grains per
ear, number of spikelets per ear, 1000 grain weight and grain yield
per plant. Statistical analysis of the split plot design was done
according to the method described by Panse and Sukhatme (1967).
Genotypic and phenotypic variances, heritability, and genetic advance
were estimated according to Burton and de Vane (1953), Johnson et al
(1955) and Robinson et al (1949), respectively. Genotypic
correlations were computed according to Al-Jibouri et al (1958) and
path coefficients following the method suggested by Dewey and Lu
(1959).
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