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Results and
Discussion
The phenotypic and genotypic correlations among grain yield and
its components in F4 progenies for two wheat crosses,
namely, WL 711 x HD 2122 (cross 1) and HD 2122 x Sonalika (cross 2)
are given in Table
1. The genotypic
correlation coefficients were higher in magnitude than the phenotypic
correlation coefficients for almost all the traits in both the
crosses. This indicated that the association between these traits was
genetically inherited. It is clear from this table that yield was
positively and significantly associated with tiller number per plant,
number of grains per ear and 1000-grain weight in both the crosses.
The direct effects of three component characters on grain yield
(Table
2) indicated that
tillers/plant had largest contribution followed by grain number and
1000 grain weight in cross 1. Jaimini et al (1974) and Quick (1978)
also found tiller number and grain number/ear having high direct
effect on grain yield. On the contrary, in cross 2, the character
1000 grain weight was having the largest contribution followed by
number of grains per ear and number of tillers per plant. Ahmad et al
(1978) and Gupta et al
(1979) also reported
high direct effect of kernel weight and grains per ear on grain
yield.
The highly, significant and positive correlation of tillers/plants in
cross 1 and 1000 grain weight in cross 2 with grain yield was
due to the substantial direct influence of these characters in the
two crosses, respectively, which were in agreement with the results
reported by Paroda and Joshi (1970). Indirect effect of tiller
number/plant via grain number/ear was also positive as compared to
that via 1000-grain weight where it was negative in cross 1. Grain
number/ear also had high positive direct effect on grain yield. Its
negative contribution via 1000 grain weight in cross 1 and via tiller
number/plant in cross 2 is approximately compensated by indirect
effects through tiller number/plant in cross 1 and 1000 grain weight
in cross 2. The 1000 grain weight in cross 1 and tiller number/plant
in cross 2 though had high positive direct influence on grain yield,
their, effects were negative through tiller nuniber/plant and grain
number/ear in cross 1 and through grain number/ear and 1000-grain
weight in cross 2, respectively. This is why their correlation
coefficients were comparatively low.
Although results of the two crosses investigated differed in respect
of maximum contribution made by component characters towards yield
(tillers/plant in cross 1 and 1000-grain weight in cross 2), the
positive and high direct effects of all three components on grain
yield in both the crosses indicated that if an increase in grain
yield is to be obtained, selection should be made for genotypes
having more number of tillers, grains/ear, and higher 1000-grain
weight. But in selection programme, there must be compromise between
these three components so that the increase in one component is not
nullified by the decrease in the other.
References
Ahmad Z, Sharma JC, Katiyar RP and Bhatia RS (1978) Path analysis
of productivity in wheat. Indian J Genet 38: 299-303.
Dewey DR and Lu. KH (1959) A correlation and path coefficient
analysis of components of crested wheat grass seed production. Agron
J 51: 515-518.
Gupta RR, Ahmad Z and Dixit RK (1979) Path-coefficient analysis in
macroni wheat. Indian J Agric Sci 49: 238-243.
Jaimini SN, Goyal SN and Tikka SB (1974) Estimation of correlation
and-path coefficient analysis of some biometric characters in wheat.
Indian J Agric Sci 44: 201-203.
Paroda RS and Joshi AB (1970) Correlation, path analysis and the
implications of discriminant function for selection in wheat.
Heredity 25: 383-392.
Quick JS (1978) Combining ability and in terrelationships among an
international array of durum wheat. In: Proc 5th Int Wheat Genet Symp
Vol 2 (ed. Ramanujam S): pp 635-647. New Delhi Indian Society of
Genetics and Plant Breeding.
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