Monday, 13 October 2025

Assessment of Genetic Divergence Using D2 Analysis in Rice (Oryza sativa L.) Germplasm | Chapter 5 | New Horizons of Science, Technology and Culture Vol. 5

 

Oryza sativa (2n=2x=24) is a diploid monocot flowering plant of the family Gramineae, which originated in Southeast Asia and is widely cultivated in the wet tropics and subtropics. India is remarkably rich in rice diversity, including cultivars, landraces, wild and weedy relatives. Genetic variability for quantitative traits is the basic component of the breeding programme for broadening the gene pool of rice and other crops. Understanding the extent and degree of genetic divergence aids in the selection of ideal parents for a breeding programme. The present investigation was conducted with 41 genotypes of Rice during Kharif 2023 under a Randomised Block Design (RBD) with three replications. Data were recorded for thirteen quantitative characters to obtain estimates of variability, heritability, genetic advance and genetic divergence through Mahalanobis’ D² analysis. The analysis of variance was worked out to test the significance of F and t-tests. Significant differences were observed among the genotypes for all the characters studied. From the findings, the highest grain yield was observed in VASUMATHI 38.9, followed by DHAN-69 34.33 based on mean performance at the Prayagraj region. The estimates of Genotypic Coefficient of Variation and Phenotypic Coefficient of Variation were consistent for all the traits, with PCV values being numerically higher than GCV values, which indicated greater genotype and environment interaction. A higher magnitude of PCV as well as GCV coefficient of variation was noted for the number of total tillers per plant (22.05) and (21.20). Whereas the lowest PCV and GCV coefficient of variation was recorded for Days to maturity (7.40 and 6.80). High estimates of heritability (above 60%) in the broad sense were recorded for all thirteen characters under study, which ranged from 92.45% number of total tillers per plant to 61.55% harvest index. along with high genetic advance for the number of spikelets per panicle (54.38), plant height (cm) (27.95), days to 50% flowering (22.93), and days to maturity (17.72). Biological yield (g) (15.33), harvest index (%) (11.06) and flag leaf length (cm) (10.05) D2 analysis distributed the 41 genotypes into six clusters.

 

The largest cluster was cluster I with 36 genotypes, followed by cluster II, III, IV, V, and VI with 1 genotype each. The highest contribution in manifestation of genetic divergence was exhibited by grain yield per plant (22.82), followed by biological yield (21.28) and test weight (12.56). The lowest intercluster distance was between cluster I and cluster IV, which was 60.58. The intercluster distance was maximum between cluster IV and VI (247.17). Overall, the study identified VASUMATHI and DHAN-69 as high-yielding genotypes, and the clustering pattern provides useful information for selecting genetically diverse parents in future breeding programmes.

 

 

Author(s) Details

Vinayak V. Thakare
Department of Genetics and Plant Breeding, SHUATS, U.P., India.

 

G. M. Lal
Department of Genetics and Plant Breeding, SHUATS, U.P., India.

 

Bineeta M. Bara
Department of Genetics and Plant Breeding, SHUATS, U.P., India.

 

 

Please see the book here :- https://doi.org/10.9734/bpi/nhstc/v5/6329

 

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