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Material and Method
The present study was carried out on 45 varieties consisting of
36 diverse varieties and four biblends (equal parts) of durum wheat
and five commercial bread wheat varieties. All the genotypes were
grown in randomized block design consisting of three replications in
3 artificially created environments as given below :
1) Normal sown, high fertility and irrigated (E1)
2) Medium fertility and restricted irrigations (E2)
3) Rainfed and low fertility (E3).
The data were recorded for traits as shown in Table
1. Stability
parameters of 45 varieties were computed using the model proposed by
Eberhart and Russell (1966).
Results and Discussion
The introduction of dwarf wheat varieties led to the striking
increase in the wheat yields all over the world. However, in
developing countries limited input conditions put considerable
constraints on the full exploitation of genetic potential of the new
wheat varieties. In developing countries like India there is large
area of rainfed wheat where annual fertilizer consumption per unit
area is also very low. Under such situation it becomes imperative to
test the wheat genotypes under rainfed, restricted
irrigation/fertility conditions to identify their predictable
response to inputs and irrigation levels. Hence G x E interaction
would be of great interest if it is estimated under aforesaid
conditions which may be more realistic to wheat growing situations.
Eberhart and Russell (1966) suggested an approach to identify stable
and responsive genotypes. According to their model, a stable genotype
is characterized by average response (unit regression) and least
deviation accompanied by high mean.
Highly significant variances due to varieties revealed the presence
of genetic variability in the material included in this study for all
the traits studied (Table
1). The linear
component of G x E interaction was significant for plant height,
tiller number, biological yield, grain yield, and harvest index.
Therefore, prediction for these traits appeared to be feasible. This
also shows the existence of additive type of gene-action for these
traits. Significance of pooled deviation for all these traits showed
that the varieties differed considerably with respect to their
response to different environments for these traits. Singh and Singh
(1980) and Jatasara and Paroda (1980) observed similar estimates of
linear proportion of G x E interaction for grain yield in bread
wheat. Kaltsikes and Larter (1970) observed the same for grain yield,
plant height and days to maturity in durum wheat. Nanda et al (1983),
in bread wheat, found larger predictable portion for plant height and
number of spikelets par spike.
Seven best varieties based on linear (b) and non-linear
(S-2d) components of G x E interaction and high mean
values are listed in Table
2. Varieties CC
530, JU 72, R 6009 gave high grain yield, b value above average and
S-2d non-significant. Therefore, these varieties were
suitable for favourable environment. However, WH 822, R 6011, HI
8078, CPAN 6038 and R 6032 produced average grain yield, b value near
unity and S-2d non-significant hence were stable and
responsive. Amongst aestivum wheat varieties C 306 was
desirable because of its average grain yield, stable and responsive
behaviour. Similar results have been reported by Chowdhury and Paroda
(1983) for C 306 variety. HD 2009 was also found to be average
performer and stable. WH 157 was suitable for favourable environment
since it had above average linear regression.
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