Genetic and molecular studies on aromatic rice germplasm for yield and quality attributing traits
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Date
2016
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JNKVV
Abstract
ABSTRACT
The present investigation entitled “Genetic and Molecular Studies on Aromatic Rice Germplasm for Yield and Quality Attributing Traits” was carried out with 103 aromatic rice genotypes, to select promising lines for breeding programme and to know the genetics for morphological (fifty eight) and biometrical (thirty one) traits in randomized complete block design with three replications at Seed Breeding Farm, JNKVV, Jabalpur during Kharif 2013 and
2014.
The objective of this study was to systematically characterize and categorize the aromatic genotypes collected from different geographical locations so that they could be easily distinguishable and distinct from one another, for feasibility in identification at various levels and to study the genetic variability, correlation coefficients, path coefficients, genetic divergence, principal component for yield and yield attributing traits and diversity analysis using SSR markers.
Characterization of aromatic genotypes concluded that the out of fifty eight morphological traits, seventeen characters had sufficient amount of variability. Thus, we find that majority of the genotypes have undergone changes from primitive types to evolved ones but there are still some genotypes, which possess primitive characters.
Analysis of variance indicated that the differences among genotypes were highly significant for all the traits studied. This indicated that the genotypes had sufficient amount of variability. The variability among aromatic genotypes ranged from spikelet density to elongation ratio. Analysis of variance indicated that the differences among genotypes were highly significant and the genotypes had sufficient amount of variability for all the traits studied. Most of the traits exhibited high heritability coupled with high genetic advance. Indicates that the heritability is most likely due to additive gene effect and selection may be effective.
Visualizing the results of correlation and path analysis it is clear that the traits harvest index, panicle weight plant-1, panicle index and biological yield plant-1 exhibited positive direct effect on grain yield per plant and also showed positive and significant association with grain yield per plant. It indicates true relationship between them and direct selection for these traits will be rewarding for yield improvement. Among the traits having negative direct effect on grain
yield per plant spikelet density and spikelet fertility percent showed positive association with grain yield per plant. It indicates that the restricted selection model should be used for nullification of undesirable effect of these traits.
One hundred and three genotypes of aromatic rice were grouped into nine clusters, which showed two multigenotypic and seven monogenotypic clusters. Cluster II showed maximum intra cluster distance values, followed by cluster I. Rest of the clusters were monogenotypic clusters consisting of one genotype each. The inter cluster D2 values were minimum between cluster III and cluster VII, while it was maximum between I and IX.
PCA was performed for thirty one agro-morphological and quality contributing traits. Out of thirty one, only 7 principal components (PCs) exhibited more than 1.59 eigen value showed about 73.14% cumulative variability. From the first seven PCs, it was clear that the PC1, PC3 and PC4 were mostly related to quality characters while PC2, PC5 PC6 and PC7 was found to be associated with yield related traits. From the above result, it is clear that Pusa Basmati 1121 and Sugandha are the best quality genotypes while regarding yield attributing traits performance of Basmati 5874 and Basmati 385 were remarkable. However, in terms of both yield and quality attributing traits Haryana Basmati 1 can be considered as best genotype.
At molecular level, a total of forty two SSR markers were used to assess the genetic diversity. Out of forty two markers, twenty eight markers were polymorphic, while remaining fourteen markers were found monomorphic. Total
82 alleles were amplified with a mean value of 1.95 across forty two SSR
markers. Unique allele was amplified by only one marker namely RM 16, While markers RM 105, RM 215, RM 241 and RM 489 amplified multiple alleles. The mean value of major allele frequency, gene diversity, heterozygosity and polymorphic information content was 0.5771, 0.5234, 0.0141 and 0.4653, respectively. The diversity analysis done based on the molecular markers, forty two aromatic rice genotypes got divided into two multigenotypic clusters viz., cluster I and cluster II. The clusters are further subdivided into subclusters and subclusters are again divided into groups showing high genetic diversity among the genotypes.
Considering, the results obtained PCA analysis, genetic diversity using morphological and molecular markers, it is clear that the genotypes included in the study are highly diverse with regards to yield and quality traits and utilization of these diverse trait specific genotypes to develop crop varieties with broad genetic base would be highly helpful for aromatic rice improvement programme
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PLANT BREEDING & GENETICS