Rice Genomics and Genetics 2015, Vol.6, No.4, 1-5
2
1 Results and Discussion
In the present investigation ADT 37 x
IR68144-3B-2-2-3 showed high mean value for the
characters
viz.,
kernel length, kernel breadth after
cooking, iron content. TRY (R) 2 x Mapillaisamba had
high mean value for the characters
viz.,
zinc content,
breadth wise expansion ratio. The genotypic and
phenotypic coefficient of variability were low in both
the crosses for the most of the traits
viz
., kernel length,
kernel breadth, kernel L/B ratio, kernel length after
cooking, kernel breadth after cooking, linear
elongation ratio and breadth wise expansion ratio
(Table 1). It indicated that all the crosses might have
attained homozygosity in F
4
itself for these traits.
These results were in accordance with Nandeshwar et
al. (2010)
who
studied F
2
progenies which were
derived from the crosses IR-62 × Samba Mashuri and
Kunti x Dudheswar and the report of Kumar et al.
(2006) in rice F
2
generation for kernel length.
Umadevi et al. (2010) recorded low genotypic and
phenotypic coefficient of variability for kernel breadth
in 110 rice genotypes. The findings of Vanaja and
Babu (2006) recorded low genotypic and phenotypic
coefficient of variability for kernel length after
cooking and kernel breadth after cooking, breadth
wise expansion ratio in 10 quality parameters in set of
56 high yielding diverse rice genotypes which is
corroborates the current investigation. For iron and
zinc content moderate GCV and PCV was observed in
F
5
generation. Hence, these traits need one or more
generations in order to attain homozygosity. These
results were in parallel with the findings of
Kalaimaghal (2011) who observed moderate GCV and
PCV for iron content in the in F
2
and F
3
the cross
ADT37 × IR68144-3B-2-2-3.
High heritability coupled with high genetic advance
was observed in ADT37 x IR68144-3B-2-2-3 only for
iron and zinc content, except TRY(R) 2×
Mapillaisamba which showed high heritability with
moderate genetic advance. Hence, these traits were
least influenced by environment and mostly governed
by additive gene action. Therefore, there is scope for
improvement of iron and zinc content by exercising
selection pressure on these two characters. These
results were in agreement with Shanmuga Sundara
Pandian (2007), Purusothaman (2010) and Aswini
Shamak et al. (2011) in F
4
and F
5
generation. Low
heritability with low genetic advance as percentage of
mean was observed for kernel length, kernel breadth
and kernel L/B ratio in all the crosses in both the
generations. The findings of Jayasree (2007) and
Umadevi et al. (2010) in genotypes observed medium
to high heritability with high genetic advance as
percentage of mean for kernel length after cooking,
kernel breadth after cooking, linear elongation ratio
and breadth wise expansion ratio which in contrast
with the result of current investigation. Based on mean,
GCV & PCV, heritability and genetic advance, it was
understood that the progenies of ADT 37 x
IR68144-3B-2-2-3 would be more useful for
improving grain iron content with the desirable quality
traits
viz
., kernel length, kernel breadth after cooking.
Similarly TRY (R) 2 × Mapillaisamba segregants
could be used for improving the grain zinc content and
breadth wise expansion ratio.
2 Material and Methods
Seeds of F
3
generation of two Cross combinations
generated from Anbil Dharmalingam, Agricultural
College &Research Institute, Trichy.
viz.,
ADT 37 ×
IR68144-3B-2-2-3, TRY (R) 2 × Mapillaisamba were
utilized as the experimental material in the present
study. Among the parents
viz
., TRY (R) 2 and ADT 37
are high yielding commercial varieties and
IR68144-3B-2-2-3 is a iron donor and Mapillaisamba
is a zinc donor which were used in earlier
hybridization programme for introgression of high
iron and zinc contributing genes. The experiment was
conducted at Agricultural College and Research
Institute, Madurai. The F
4
generation was raised
during August to November, 2011 and F
5
generation
during December 2011 to April 2012 respectively. The
F
4
progenies were raised along with their parents in
randomized block design with two replications. A total
of five families were selected from each cross
combination based on high iron and zinc content in F
3
population. For each family, 75 seedlings per
replication were raised with a spacing of 20 cm
between the rows and 15 cm between the plants. Each
family had five rows of 15 single plants each. The
recommended agronomic practices were followed
throughout the crop growth period. Five single plants
per family per replication were randomly selected and
forwarded as single plant progeny row in F
5
generation. The mean data after computing for each
character subjected to standard method of analysis of
variance following Panse and Sukhatme (1967),
