GENETIC ANALYSIS OF GRAIN YIELD AND ITS COMPONENTS IN MAIZE (Zea mays L.) 2902
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Date
2019-07
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JAU, JUNAGADH
Abstract
In the present investigation, the experimental material comprised of 7 parents,
its 21 single cross hybrids produced through diallel mating design without reciprocals
and standard check GAYMH-1. The experimental materials were grown in randomized
block design in three replications at Cotton Research Station, Junagadh Agricultural
University, Junagadh during Rabi 2018-19. The objectives of this investigation was to
study the performance of parents and hybrids, magnitude of heterosis and their
combining ability.
Analysis of variance indicated the significance differences among the parents
for all the traits which revealed existence of variability in the genotypes. Analysis of
variance indicated the significance difference among the hybrids for all the 12 traits
studied which revealed differences among the hybrids.
A marked degree of significant desired heterosis over standard check
GAYMH-1 was observed in many hybrids for most of the quantitative characters.
Among 21 hybrids, 6 hybrids exhibited positive heterosis for kernel yield over better
parent. Maximum significant positive standard heterosis over standard check GAYMH 1 for kernel yield per plant was exhibited by CM-500 × GYL-2 (32.66%) followed by
IL 14-53 × GYL-4 (26.25%) and LM 13-2 × GYL-8 (25.01%). The high heterotic
response in these hybrids for kernel yield per plant resulted due to useful significant
heterotic effects for their yield contributing characters like ear length, ear girth, number
of kernel rows per ear, number of kernels per ear, 100 kernel weight and shelling
percentage.
The analysis of variance for combining ability revealed that mean sum of
squares due to general combining ability were found significant for all the traits except
plant height, ear length and kernel yield per plant. Whereas, the specific combining
ability effects were found significant for all the characters except ear girth. The SCA
variance component was observed to be higher than the corresponding GCA variance
component for all the trait indicating the preponderance of non-additive gene action for
inheritance of these traits. All the parents were average combiner for kernel yield per
plant. CM-500 and GYL-8 were good general combiners for days to 50% tasseling,
Major Guide
Dr. L. K. Dhaduk
Name of Student
Patel Aneri V.days to 50% silking and ear height, GYL-2 were good combiner for the ear height and
days to 75% dry husk. parent LM 13-2 good combiner for the ear girth and also average
combiner for the number of kernels per row, 100 kernel weight, kernel yield per plant
and shelling percentage. The parents CM-500 and IL 14-53 good combiner for the 100
kernel weight and average combiner for the ear girth, number of kernels rows per ear,
number of kernels per row, kernel yield per plant and shelling percentage.
The estimate of sca effects reveled that none of the crosses was consistently
superior for all the characters. However, best three hybrids on the basis of significant
positive sca effects for kernel yield per plant were CM-500 × GYL-2, IL 14-53 × GYL 4 and CM-500 × IL 14-53. These crosses also registered significant and positive sca
effects for most of its yield attributes viz., ear length, ear girth, number of kernels per
row, number of kernels per ear, 100 kernel weight and shelling percentage. The highest
significant sca effects in desired direction for various characters was exhibited by
different hybrids viz., GYL-2 × GYL-8 for days to 50% tasseling, CM-500 × IL 14-53
for days to 50% silking, HKI-163 × GYL-8 for plant height, LM 13-2 × HKI-163 for
ear height, GYL-2 × GYL-8 for days to 75% dry husk, CM-500 × GYL-8 for ear length,
IL 14-53 × HKI-163 for ear girth, CM-500 × GYL-8 for number of kernels rows per
ear, CM-500 × GYL-8 for number of kernels per row, GYL-2 × GYL-8 for 100 kernel
weight and LM 13-2 × GYL-4 for shelling percentage.
On the basis of per se performance, exploitable heterosis, gca effects,sca effects
and gene action involved in the expression of kernel yield per plant and its component
characters, CM-500 × GYL-2, IL 14-53 × GYL-4 and LM 13-2 × GYL-8 were found
promising and may be exploited commercially after critical evolution for its superiority
and stability across the locations and over years.
The estimate of genetic components of variation revealed significant
differences for variance due to additive genetic effect (D) as well as variance due to
non-additive effects (H1 and H2) for all the characters except ‘D’ for days to 50%
tasseling, Days to 50% silking, plant height , ear height,100 kernel weight, kernel yield
per plant, shelling percentage. The average degree of dominance (H1/D)1/2 was found
to be greater than unity for all the traits. The non-significant estimate of ‘E’ for all the
traits except kernel yield per plant, days to 50% tasseling, days to 50% silking, ear
height, ear length suggested that there was no considerable environment influence
modifying their expression. Asymmetrical distribution of positive and negative genes
in the parents was observed for most of the traits, while symmetrical distribution was
observed for number of kernels per row. KD/KR ratio more than unity for days to 50%
silking, plant height, ear height, days to 75% dry husk, ear length, ear girth, number of
kernel rows per ear, 100 kernel weight, kernel yield per plant and shelling percentage
showed an excess of dominant gene in the parents, while KD/KR ratio less than unity
for days to 50% tasseling and number of kernels per row indicated an excess of
recessive gene in the parents. Moderate estimates of heritability in narrow sense was
observed for days to 50% tasseling, days to 50% silking, ear height, ear girth and
number of kernels per row. Low heritability was observed in plant height, days to 75%
dry husk, ear length, number of kernel rows per ear, 100 kernel weight, kernel yield per
plant and shelling percentage.