Character associations and genetic diversity in bread wheat using molecular markers
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Date
2017
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CCSHAU
Abstract
The present investigation entitled, “Character associations and genetic diversity in bread wheat using
molecular markers” was conducted during rabi 2015-16 to evaluate 167 bread wheat genotypes in order to
determine variability, heritability, genetic advance, correlation among the traits and path analysis along with genetic
diversity analysis both at phenotypic and molecular level. The genotypes were also screened for yellow rust using
modified Cobb’s scale. The experimental material was grown in Randomized Block Design (RBD) with three
replications at Research Farm of Department of Genetics and Plant Breeding, CCS HAU, Hisar. All the genotypes
showed enough genetic differences for fourteen characters, namely, days to heading, number of tiller per plant, flag
leaf length (cm), flag leaf breadth (cm), flag leaf area (cm2), plant height (cm), ear length (cm), number of grains per
ear, number of spikelets per ear, ear weight (g), 1000-grain weight (g), grain yield/ plant (g), biological yield/ plant
(g) and harvest index (%).The maximum value of genotypic as well as phenotypic coefficients of variation was
observed for grains per ear (17.16 %), (24.08), respectively. Number of tiller per plant, ear length, ear weight, grain
yield per plant and biological per plant recorded high heritability along with high genetic advance which revealed
the presence of additive gene effects indicating effectiveness of selection for these traits in wheat improvement.
Number of tillers per plant, 1000-grain weight, ear weight, grain weight per ear, number of grains per ear, flag leaf
area and ear length showed positive and significant correlation (both phenotypic and genotypic) with grain yield per
plant. Nine traits showed direct effect towards grain yield per plant. Ward method based on Euclidean minimum
distance divided 167 genotypes into twelve major clusters in such a way that genotypes within each cluster had
smaller value than those between clusters. Highest intra-cluster distance was found in cluster IV (4.539) while
Cluster II and cluster VIII showed maximum inter cluster distance (9.263). 167 genotypes were screened using
modified Cobb’s Scale, out of which, 127 showed 0 % infection against yellow rust and maximum infection was
observed in AL23, AL30 and PBW 343. Genotypes which showed 0% infection were resistant to yellow rust and
could be utilized for breeding programme aimed toward disease resistance. Genetic diversity was studied at
molecular level by using 29 SSR markers, out of which, 15 were found polymorphic, 4 were not amplified while ten
were found monomorphic. Number of alleles ranged from 2-3 with an average of 2.47. PIC values of various SSR
loci ranged from 0.131 (cfa 2164) to 0.673 (barc 146). Cluster tree analysis based on UPGMA following the
software NTSYS PC led to grouping of 167 genotypes in 2 major clusters at 0.53 similarity index. Cluster I, which
is biggest, comprised of 162 genotype while Cluster II comprised of only 5 genotypes. Precise information on the
nature and degree of genetic variability and divergence present in studied wheat genotypes would help to select
parents for evolving superior varieties.
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