CHARACTERIZATION OF RICE GENOTYPES FOR MORPHOLOGICAL, PHYSIOLOGICAL AND QUALITY TRAITS
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Date
2023-12-02
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Acharya N G Ranga Agricultural University
Abstract
The present investigation was carried out during kharif, 2020 at Agricultural College Farm, Bapatla with 30 genotypes to elicit information on the nature and extent of variability, heritability, genetic advance as per cent mean for morphological, physiological and quality traits; association among yield, yield components, physiological and quality traits; direct and indirect effects of morphological, physiological and quality traits on grain yield and to evaluate the molecular diversity among 30 rice genotypes using SSR markers.
The analysis of variance for morphological, physiological and quality traits revealed significant differences among the genotypes for all the characters under study indicating the existence of sufficient variation among the genotypes studied. The estimates of phenotypic coefficient of variation for all the characters under study were high than the genotypic coefficient of variation and the variation is less between these two estimates indicating meager influence of environment on the expression of these traits. The results of genetic parameters among morphological, physiological and quality traits revealed high GCV, PCV, heritability and genetic advance as per cent mean for grain yield per plant, volume expansion ratio among yield and quality traits whereas, LAI at tillering; net assimilation rate; root dry matter at harvesting; stem dry matter at tillering, panicle initiation and flowering stage; leaf dry matter and panicle dry matter at all phenophases and total dry matter at tillering and panicle initiation stages among physiological traits indicating the pre-ponderance of additive gene action and therefore, there is an ample scope for the improvement of these traits through selection.
The perusal of results on character association between yield, yield components, quality and physiological parameters revealed positive and significant association of grain yield per plant with root length at harvesting and harvest index at both phenotypic and genotypic levels; test weight, relative water content at 30 DAT and relative water content at 60 DAT at genotypic level indicating an increase in grain
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yield with improvement of these characters. Hence, priority should be given to these traits while making selection for grain yield improvement.
The results on path analysis revealed positive and significant association of relative water content at 30 DAT, 60 DAT and root dry matter at harvesting with grain yield per plant in addition to high and positive direct effects on grain yield per plant indicating the effectiveness of direct selection for these traits would result in improvement of grain yield per plant.
The molecular diversity studies of 30 genotypes using 19 SSR markers revealed that out 19 markers, 13 markers showed polymorphism. Among 13 polymorphic markers, the marker RM219 exhibited highest PIC value of 0.78 followed by RM431 (0.64) and RM60 (0.62). The marker RM279 produced maximum of four alleles whereas, the marker RM431 recorded maximum number of effective alleles, high Shannon‟s information index and high genetic diversity index. High PIC markers are more informative and can effectively distinguish the genotypes. The results of cluster analysis by using UPGMA method revealed that all the 30 genotypes were grouped into two major clusters. Cluster I was the largest cluster which was further separated into two clusters IA with nine genotypes and IB with 14 genotypes whereas, cluster II comprised of seven genotypes.
Out of seven markers that were associated with the reported QTLs for different traits, only three markers RM228, RM240 and RM430 were found to be associated with spikelet fertility percentage, harvest index and test weight & grain yield per plant respectively in the present study. Hence, these markers may be utilised as linked markers in marker assisted selection.