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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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