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Results and Discussion
The analysis of variance for combining ability revealed that
variances due to general and specific combining abilities
were significant for latent period and pustule size. Some
good general combiners and specific cross combinations along
with their per se performance for latent period and
pustule size are presented in Table
1.
An overall appraisal of general combining ability
(gca) effects in the present study showed that parent
P1438 was the best general combiner for latent period as
well as for pustule size. Therefore, this parent could be a
good choice in breeding programmes for the improvement of
these characters. The parent WH331 showed a high gca
effect and had relatively shorter pustule size and
considerably longer latent period whereas the susceptible
cultivar Agra local showed the poorest gca effects
for both latent period and pustule size. For latent period,
P1501 x P1523 was found to be a good cross combination. One
of the parents in this cross was good general combiner for
long latent period. This cross can give good segregants for
resistance to leaf rust in subsequent generations. The cross
combinations WH157 x P1486 and WH283 x P1438 showed
significantly high specific combining ability (sca)
effects for latent period. For pustule size P10015 x Agra
local showed the highest sca effect followed by
P10015 x P1523. These crosses could be expected to give
desirable transgressive segregants.
References
GRIFFING, B. 1956. Concept of general and specific combining
ability in relation to diallel crossing systems. Aus. J.
Biol. Sci 9: 463-493.
KUHN, R.C., W.H. OHM & G.E SHANER, 1978. Slow leaf
rusting resistance in wheat against twenty-two isolates of
Puccinia recondita. Phytopathology 68:
651-656.
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