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Perumalsamy S.,Tamil Nadu Agricultural University | Bharani M.,Tamil Nadu Agricultural University | Sudha M.,Tamil Nadu Agricultural University | Nagarajan P.,Tamil Nadu Agricultural University | And 4 more authors.
Plant Breeding | Year: 2010

Evolving high yielding rice genotypes with durable resistance to bacterial leaf blight (BLB) is pertinent considering the extensive damage caused by the disease in most of the rice growing regions. Two high yielding BLB susceptible indica rice cultivars, 'ADT43' and 'ASD16' popular among farmers and consumers across South India have been introgressed with three BLB resistance genes xa5, xa13 and Xa21 from isoline IRBB60 using functional markers. The F 2 populations of 500 plants from ADT43 × IRBB60 and 806 plants from ASD16 × IRBB60 crosses were screened for the presence of all the three resistance genes. Thirty genotypes with three genes in homozygous and 55 genotypes with two genes in homozygous and one gene in heterozygous condition were identified. These pyramided genotypes with two or three resistance genes exhibited high levels of resistance against two predominant Xanthomonas oryzae isolates of South India. Among the 30 pyramided genotypes (xa5 + xa13 + Xa21), 12 were found to be significantly high yielding with desirable agronomic characteristics and the selection efficiency of the present markers was hundred percent. © 2009 Blackwell Verlag GmbH.

Bharani M.,Tamil Nadu Agricultural University | Nagarajan P.,Tamil Nadu Agricultural University | Rabindran R.,Tamil Nadu Agricultural University | Saraswathi R.,Tamil Nadu Rice Research Institute | And 2 more authors.
Archives of Phytopathology and Plant Protection | Year: 2010

Marker assisted selection was employed to pyramid three bacterial blight resistance genes Xa21, xa13 and xa5 into high yielding susceptible rice cultivars ADT43 and ADT47. With the assistance of PCR markers, homozygous and heterozygous genotypes were identified in F2 generation of two crosses (ADT43 6 IRBB60 and ADT47 6 IRBB60) and goodness of fit was tested. Eighty nine plants from F3 generation of ADT43 6 IRBB60 were also screened for resistance genes.The genotypes carrying resistance genes in different combinations were identified. The pyramided lines showed a wider spectrum and higher level of resistance against two Xoo isolates under field conditions. © 2010 Taylor & Francis.

Maavimani M.,Agricultural College and Research Institute | Saraswathi R.,Tamil Nadu Rice Research Institute
Indian Journal of Genetics and Plant Breeding | Year: 2014

The effect of high temperature at anthesis on spikelet fertility was studied in 22 rice genotypes selected from 98 heat tolerant genotypes. Genotypes were grown in field under natural conditions in Randomized Block Design replicated twice till vegetative stage. Before booting stage, few plants were transferred to pots and placed in polyhouse for high temperature treatments. On the first day of anthesis (i.e. the appearance of anthers), plants were transferred into polyhouse with temperatures gradually increasing from 29°C to 40°C and maintained at 40°C until 15 h, with a relative humidity of 75 percent. Seven genotypes viz., IR 86970-145-1, IR86977-140-2, IR 86977-141-3, IR86977-95-1, IR 86970-126-3, IR 86977-92-3 and IR 86977-104-1 exhibited 20 to 40 per cent spikelet fertility after exposure to high temperature of 40°C. The pollen fertility ranged from 39.0 to 90.5 per cent. The genotype IR 86970-145-1 had significant value for anther length (2.125) and anther breadth (0.320). Anther dimensions seem to have an influence on anther dehiscence, pollen and spikelet fertility. All other genotypes were found to be sterile with no seed set. Exposure to high temperature during heading has significantly reduced the spikelet fertility but there were genotypic differences. © 2014, Indian Society of Genetics and Plant Breeding. All rights reserved.

Sable A.,Tamil Nadu Agricultural University | Suresh S.,Tamil Nadu Rice Research Institute | Mohan Kumar S.,Tamil Nadu Agricultural University
Ecology, Environment and Conservation | Year: 2015

Antibiosis of five selected genotypes against brown planthopper (BPH) Nilaparvata lugens was studied under glass house conditions. Number of probing marks by BPH was higher and feeding rate and adult longevity was lower on all test genotypes as compared to susceptible check TNI. BPH produced highest number of probing marks on RP 2068-18-3-5 (27.88/plant). Feeding rate of BPH females was measured by honeydew excretion area over 24 hours. On test genotypes, feeding rate ranged from 58.13 to 277.50 mm2 and 22.63 to 178.88 mm2 on 40 and 60 day old plants respectively which were significantly lower than TNI. Longevity of adults was significantly lower ranging from 4.05 to 7.12 days on all genotypes compared to 9.69 days on TNI. Plant resistance appeared to be increasing with increasing age irrespective of resistance level. Copyright © EM International.

Pandian S.S.,Tamil Nadu Agricultural University | Robin S.,Tamil Nadu Agricultural University | Vinod K.K.,Tamil Nadu Agricultural University | Vinod K.K.,Indian Agricultural Research Institute | And 5 more authors.
Australian Journal of Crop Science | Year: 2011

Rice as the major staple food of the world although is high in calories but deficient in essential micronutrients. This deficiency can be tackled by biofortification of rice grains with enhanced micronutrient content. Field experiments were carried out across three locations involving 17 genotypes, with the objective of assessing the genotype × environment interaction for native soil micronutrient assimilation in rice kernels and the influence of intrinsic soil variables on micronutrient content in rice grains. Contents of Fe, Zn, Cu and Mn in the milled kernels were found to vary significantly among genotypes and locations. There was significant genotype-byenvironment interaction (GEI) for all the nutrients. Further, it was found that soil pH and soil available P had significant influence towards grain Fe content. Soil Zn availability and the electrical conductivity of the soil solution were found closely associated with grain Zn content. The two factors that regulated Cu and Mn content of rice grains were soil organic carbon content and soil Cu availability. The factorial regression (FR) approach to assess the role of significant intrinsic soil factor (s) on enrichment of specific micronutrient in the milled rice kernels showed differential genotype responses that ultimately determined grain micronutrient accumulation in each genotype. These determinants enabled prediction of genotypes suited to different environments. In certain cases, further examination of environmental co-factors is advocated to bring out a comprehensive picture of the micronutrient assimilation in milled rice grains.

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