Browsing by Author "A. Anandan"

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Deciphering environmental factors and defense response of rice genotypes against sheath blight disease
(Academic Press, 2022) R. Naveenkumar; A. Anandan; Vineeta Singh; S.R. Prabhukarthikeyan; C. Parameswaran; G. Sangeetha; A. Mahender; U. Keerthana; P.K. Singh; B.C. Patra; Jauhar Ali
Sheath blight (ShB) is one of the most serious diseases in rice, leading to severe yield losses globally. In our study, we evaluated a total of 63 rice genotypes for resistance against sheath blight disease by artificial inoculation over two seasons under field conditions and studied the weather parameters associated with disease incidence. Based on two years of testing, 23 genotypes were found moderately resistant, 38 were moderately susceptible, and 2 exhibited a susceptible reaction to sheath blight disease. Among the specific four genotypes (IC283139, IC283041, IC283038, and IC283023) of the moderately resistant group exhibited less disease reaction in comparison with check variety Tetep. Further, the correlation of percent disease index (PDI) with weather parameters revealed negative associations between PDI and maximum temperature, minimum temperature, low rainfall and the positive association with maximum relative humidity (RH) suggest that very low temperature or high precipitation might have a negative impact on pathogen establishment. In addition, the sheath blight-linked SSRs were assessed using distance and model-based approaches, results of both the models revealed that genotypes distinguished the resistant population from the susceptible one. From the output of two years of principal component analysis, two genotypes from each group of moderately resistant, moderately susceptible and susceptible were studied for their biochemical reaction against the sheath blight pathogen. The biochemical study revealed that the accumulation of defense and antioxidant enzymes, namely, polyphenol oxidase, peroxidase, total phenol, phenylalanine ammonia-lyase, catalase, and superoxide dismutase, were higher in moderately resistant genotypes, but was observed to be lower in moderately susceptible and susceptible genotypes. The statistical analysis revealed the enzyme activities (defense and antioxidant) exhibited a strong negative correlation with area under the disease progress curve (AUDPC) and influence of weather parameter RH. This demonstrates that the environment factor RH plays a major role in imparting the resistance mechanism by decreasing the enzymes activities and increasing PDI. This study found that the identified novel resistant genotype (IC283139) with purple stem base demonstrated improved resistance against sheath blight infection through a defense response and the use of antioxidant machinery. © 2022 The Authors
Pattern of genetic variation in rice (Oryza sativa l.) population for sheath blight resistance over the seasons
(Indian Society of Genetics and Plant Breeding, 2021) R. Naveenkumar; Vineeta Singh; P.K. Singh; A. Anandan
A set of 192 indica rice accessions were evaluated in two seasons to generate information on the extent of genetic variability, broad-sense heritability and genetic advance for yield and sheath blight related traits. The estimated genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) varied over the season. Largely, PCV values were relatively higher than GCV with reference to the studied parameters. However, GCV was found to be medium for per cent disease index (PDI) of 14th day, 28th day, area under the disease progress curve (AUDPC), and tiller number over the seasons. Interestingly, grain yield was found to be high. The trait plant height and panicle length had moderate heritability coupled with moderate genetic advance, whereas AUDPC was moderately heritable coupled with high genetic advance. The findings may be useful in breeding improved rice genotypes. © 2021, Indian Society of Genetics and Plant Breeding. All rights reserved.
Variabilty for sheath blight (Rhizoctonia solani Kuhn.) resistance in Indica rice germplasm
(Springer, 2024) R. Naveenkumar; A. Anandan; Vineeta Singh; Shyam Saran Vaish; P.K. Singh
In the present study, 325 rice accessions comprising of improved varieties and landraces were obtained from different states of India and were screened against Rhizoctonia solani (AG1-IA). The rice accessions were transplanted with established moderately resistant (Tetep, Jasmine 85, and Teqing) and susceptible checks (Pusa Basmati-1 and Tapaswini). The correlation coefficient among the traits associated with sheath blight-related traits such as RLH and PDI and other morphological traits, viz., plant height (cm), panicle length (cm), tiller number plant− 1, and days to 50% flowering (days)were computed. At the booting stage, immature sclerotia of R. solani (AG1-IA) were inoculated with plants to evaluate the rice genotypes against sheath blight. Among all the accessions screened, 55 entries were moderately resistant and none of the test entries was found resistant. The computed correlation revealed a significant positive correlation among the different days of PDI and RLH with respect to the disease. Among the different morphological and sheath blight related parameters studied, a wide range of variation was observed among the traits. © 2024, The Author(s) under exclusive licence to Society for Plant Research.