Time filter

Source Type

Vijay Krishna Kumar K.,Auburn University | Vijay Krishna Kumar K.,Acharya N.G. Ranga Agricultural University | Yellareddygari S.K.R.,Auburn University | Reddy M.S.,Auburn University | And 7 more authors.
Rice Science | Year: 2012

Rice sheath blight disease (ShB), caused by Rhizoctonia solani, gives rise to significant grain yield losses. The present study evaluated the efficacy of Integral®, the commercial liquid formulation of Bacillus subtilis strain MBI 600, against rice ShB and for plant growth promotion. In greenhouse studies, four log concentrations of Integral (from 2.2×10 6 to 2.2×10 9 cfu/mL) were used as seed treatment (ST). After 25 d, seedlings were dipped (SD) into Integral prior to transplanting. At 30 d after transplanting (DAT), leaf sheaths were inoculated with immature sclerotia of the pathogen. At 45 DAT, a foliar spray (FS) with Integral was applied to some treatments. The fungicide control was 50% carbendazim at 1.0 g/L, and a nontreated control was also included. Overall, there were 10 treatments, each with five replications. ShB severity was rated at 52 DAT, and seedling height and number of tillers per plant were rated at 60 DAT. In 2009, two field trials evaluated Integral at 2.2×10 8 and 2.2×10 9 cfu/mL. Integral was applied as ST, and seedlings were produced in a nursery bed. After 32 d, seedlings were treated with Integral as SD and transplanted into 10 m 2 blocks. Foliar sprays were given at 45 and 60 DAT. There were seven treatments, each with eight replications arranged as a factorial randomized complete block design. At 20 DAT, the plots were broadcast inoculated with R. solani produced on rice grains. Seedling height before transplanting, ShB severity at 90 DAT, and grain yield at harvest were recorded. Integral at 2.2×10 9 cfu/mL provided significant increase of seedling heights over other treatments under greenhouse conditions. The Integral treatments of ST + SD + FS at 2.2×10 9 cfu/mL significantly suppressed ShB over other treatments. In field studies, Integral provided significant increase of seedling height in nursery, and number of tillers per plant, compared with the control. ShB severity was significantly suppressed with higher concentrations of Integral compared to lower concentrations. Grain yield were the highest at an Integral concentration of 2.2×10 9 cfu/mL. Overall, Integral significantly reduced ShB severity, enhanced seedling growth, number of tillers per plant and grain yield as ST + SD + FS at the concentration of 2.2×10 9 cfu/mL under the conditions evaluated. © 2012 China National Rice Research Institute.


Rani M.G.,Andhra Pradesh Rice Research Institute | Satyanarayana P.V.,Andhra Pradesh Rice Research Institute | Ahmed M.L.,Andhra Pradesh Rice Research Institute | Ahmed M.L.,P.A. College | And 3 more authors.
Research on Crops | Year: 2015

Knowledge of gene action on yield and lodging related traits would help in framing suitable breeding strategy for the development of lodging resistance genotypes with high yield. Present investigation aimed at studying gene action among the eight yield and six lodging resistance related traits in two crosses MTU 7029/II 110-9-1-1-1-1 and MTU 7029/MTU 1121 using six-parameter model of generation mean analysis. The results revealed significance of scaling test for all the traits indicating inadequacy of additive dominance model for explanation of inheritance of 14 traits in both the crosses except for number of ear bearing tillers/plant, test weight and grain yield/plant in case of MTU 7029/MTU 1121. In both the crosses, characters number of filled grains/panicle, spikelet fertility, test weight, culm diameter and panicle length expressed complementary epistasis besides dominance x dominance interaction. Hence, biparental mating followed in early generations and selection could be practised in advanced generations to fix favourable alleles. Rest of the traits such as number of ear bearing tillers/plant, grain yield/plant, culm thickness, culm strength, basal internodal length and per cent of lodging exhibited duplicate type of epistasis. Characters with non-additive gene action coupled with duplicate type of gene interaction can be improved by recurrent selection or diallel selective mating.


Vijaya Lakshmi B.,Andhra Pradesh Rice Research Institute | Srinivas B.,Andhra Pradesh Rice Research Institute | Vinay Kumar M.,Andhra Pradesh Rice Research Institute | Vijay D.,Andhra Pradesh Rice Research Institute
Current Trends in Biotechnology and Pharmacy | Year: 2010

Phenotypic response of the 16 rice genotypes to brown plant hoppers (BPH) was evaluated at flowering stage under field conditions. The results indicated that genotypes were classified into five groups from score 1 to score 9. A total of 88 alleles were detected by 37 polymorphic markers with an average of 2.17. Polymorphic information content (PIC) value varied from 0.92 for RM 483 to 0.98 for RM 84, with an average of 0.95. An efficient separation of 16 rice genotypes based on SSR data into three groups was achieved by using unweighted pair group method with arithmetic means (UPGMA) clustering procedure based on genetic similarity expressed by the Jaccard similarity coefficient (JSC). Genotypes that are derivatives of genetically similar type clustered more together. The results also indicated that land races which are potential sources for biotic stress exhibited wide range of reaction from score 1 (slight drying) to score 9 (all plants apparently dead) to brown plant hopper screening and therefore very useful for rice breeding programs, especially for genetic mapping studies and eventually for application of marker-assisted selection (MAS). From this study it was concluded that mapping population could be developed by using PTB 33 and BM 71 as donors to introgress genes for BPH resistance into cultivated high yielding rice cultivars.


Rani M.G.,Andhra Pradesh Rice Research Institute | Lakshmi B.V.,Andhra Pradesh Rice Research Institute | Adilakshmi D.,Andhra Pradesh Rice Research Institute | Ravi Kumar B.N.V.S.R.,Andhra Pradesh Rice Research Institute | And 5 more authors.
Research on Crops | Year: 2013

Neck blast is more destructive among rice blast symptoms causing economic yield loss. Detection of presence of blast resistant genes in resistant donors using molecular markers will aid in breeding location specific resistant varieties with precise marker assisted breeding. Simple sequence repeat marker RM 224 linked to Pi-1 blast resistant gene was found to be polymorphic between susceptible parent Samba Mahsuri and neck blast resistant donor WGL 167. Polymorphic bands between resistant and susceptible bulks with RM 224 marker indicated that Pi-1 blast resistant gene conferred neck blast resistance in donor WGL 167 through bulk segregant analysis of BC2F2 mapping population developed between Samba Mahsuri and WGL 167 and it was confirmed by field screening of individual BC2F2 BC 2F3 and BC2F4 lines. Results of composite interval mapping revealed that one major effect quantitative trait loci (QTL) flanked by SSR markers RM 187 and RM 224 on chromosome 11 with LOD peak value of 11.3 accounting for 55.53% phenotypic variation of neck blast disease reaction. Three lines with more than 70% recurrent genome recovery with 0 or 1 neck blast score were selected through graphical genotyping using back ground selection markers from BC2F3 and BC 2F4 population of Samba Mahsuri and WGL 167. Presence of blast resistant gene Pi-1 against avirulence genes of local pathotype in neck blast resistant donor WGL 167 was detected through bulk segregant analysis.


Rani M.G.,Andhra Pradesh Rice Research Institute | Adilakshmi D.,Andhra Pradesh Rice Research Institute
Journal of Crop Improvement | Year: 2011

Gene-linked markers are powerful tools to detect the presence of gene(s) for rice (Oryza sativa) blast resistance; they are useful in conducting marker-assisted selection. Eight genotypes of rice were used for genetic analysis with 85 gene-linked SSR markers for rice blast resistance and defensive response genes to study the parental polymorphism between resistant and susceptible genotypes. PCR-amplification results revealed that 39 primers out of 85 exhibited distinct polymorphism among the eight genotypes. The number of alleles varied from 2 to 4, with a mean of 2.26. The genetic associations among eight genotypes were examined via unweighted pair group method with arithmetic mean (UPGMA) analysis. Cluster analysis revealed that two blast-resistant genotypes (WGL167 and NBR 16) and susceptible genotype (BPT 5204) were grouped into cluster I, showing polymorphic loci for RM 138 (pib) and RM 3330 (pi40) gene-linked markers. Three other blast-resistant genotypes (NBR 11, MTU 1003, and NLR 34449) and a susceptible genotype (MTU 2077) were grouped into cluster II, exhibiting polymorphic loci for RM 144 (piK-S) gene-linked marker. Cluster III had only one susceptible genotype, MTU 3626. The susceptible and resistant genotypes exhibited polymorphic alleles for RM 6468 and RM 260 (oxalate oxidase), RM 542 (thaumatin), and RM 5426 (DHAP) candidate gene co-localized markers. Efficiency of detecting blast-resistance gene depended on genotypes and gene-linked markers. These results indicated scope for utilization of blast-resistant genotypes with detected gene-linked markers in marker-assisted selection. © Taylor & Francis Group, LLC.

Loading Andhra Pradesh Rice Research Institute collaborators
Loading Andhra Pradesh Rice Research Institute collaborators