(go to
KOMUGI Home) (go
to WIS List) (go to NO.79
Contents)
Materials and Methods
Ten varieties of bread wheat [Triticum aestivum (L.)
Thell], namely, Moncho, Pavon, Brochis, Chiroca, HD 2204, Raj
1482, WL 711, Raj 821, D 65 and Kharchia 65, were crossed in all
possible combinations excluding reciprocals. The resulting 45
F1's were grown to get F2's seeds. Parents
along with their 45 F1's and F2's were grown in
a randomised block design with three replications under early, normal
and late sown conditions (environments). Each plot consisted of
single 5m row length of parent and F1 and 10 rows of
F2 with the spacing of 30 cm between rows and 15 cm
between plants. Ten competitive plants in parents and F1's
and twenty plants in F2 progenies were selected randomly
for recording observations (Table
1) under each
environment separately.
The mean of each plot was used for statistical analysis. The data
were first subjected to the usual analysis followed for a randomised
block design for pooled over environments. The combining ability
analysis was done following Method 2, Model 1 of Griffing (1956).
Results and Discussion.
Pooled analysis of variance over the environments revealed highly
significant differences amongst them. So was true for genotype x
environment interactions.
The analysis of variance for combining ability for the data pooled
over three environments (Table
1)
showed that mean
squares due to general combining ability (gca) and specific combining
ability (sea) were significant for all the traits studied in both
F1 and F2 generations except tiller number and
variance due to gca for grain yield, sea for days to heading, number
of spikelets per spike in F1 generation, sea for number of
grains per spike in F2 generation, signifying the
importance of both additive and non-additive gene effects in
controlling the inheritance of yield and its component traits.
However, the gca variance was found higher than sea variance in both
the generations, indicating the preponderance of additive gene
effects for yield components but for grain yield sea variance was
predominant. The findings of Jaimini and Mathur (1980), Shrivastava
et al. (1981), Sharma and Singh (1983), Sharma et al. (1986), Rajora
(1992), Singh et al. (1993) and Solanki et al. (1993) are in
agreement with the present results. Results further revealed that
tiller number, days to heading, number of spikelets per spike and
number of grains per spike were highly influenced by the genotype
environmental interaction. This is corroborated by the estimates of
heterosis as heterosis for these traits was non-significant.
Both the gca and sea exhibited highly significant interaction with
the environments for yield and its components in both the
generations, indicating the role of environment in influencing the
gene effects. Other studies (Jatasara and Paroda 1981; Shanna and
Singh 1982; Kumar et al. 1983; Singh et al. 1986; Dasgupta and Mondal
1988) substantiate this point. However, gca x environment interaction
variances were higher than sea x environment variances for all the
traits except grain yield in both the generations, further signifying
the importance of additive genetic variance for yield components.
<--Back | -->Next
(go to
KOMUGI Home) (go
to WIS List) (go to NO.79
Contents)