Genetic variability of root traits of different classes of rice (Oryza sativa L.) in Assam
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Date
2020-10
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Publisher
AAU, Jorhat
Abstract
Root characters for plant selection have been major breeding objectives for
development of stress tolerant varieties in rice. Therefore the present
investigation was conducted for comparative study of root traits and some yield
attributing traits in different classes of rice (Ahu, Sali, Bao and Hybrid) in Assam.
The study revealed presence of genetic variability among the genotypes for all the
root and yield attributing traits. Bao varieties showed maximum root development
throughout its growth period upto maturity in comparison to the other classes of
rice. Highest phenotypic coefficient of variation and genotypic coefficient of
variation was observed for the root length, root volume and root: shoot ratio.
Heritability in broad sense was found to be high for root length, plant height, root
volume and root: shoot ratio. Genetic advance as percentage of mean was found
to be maximum for the root: shoot ratio, root volume and root length. High
heritability along with high genetic advance as percentage of mean indicates
presence of additive gene action and simple selection procedure can be adopted
for improvement of yield. Correlation coefficient revealed positive association of
fresh root weight, root: shoot ratio, total tillers per plant, effective tillers per plant
with grain yield per plant respectively at genotypic level. Higher genotypic
correlation coefficient indicates less influence of environmental effects on traits.
Genotypic path analysis revealed 1000-grain weight, fresh shoot weight showed
highest positive direct effect on grain yield. D2 analysis revealed total 11 numbers
of clusters and cluster I and cluster VII showed highest numbers of genotype (5
each). Contribution of traits to total divergence was observed highest for root
length followed by root volume and plant height. Inter cluster average distance
was found to be maximum between cluster VIII and XI; IV and VIII and intra
cluster average distance was found to be maximum for cluster I followed by
cluster VII and cluster II. Clustering pattern of the genotypes revealed it did not
follow any particular pattern with respect to the origin of the genotypes. Parental
lines selected from cluster IV, VIII and XI can be used for hybridization
programme.