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Not AvailableIn order to understand the pathogen’s genetic diversity and dynamics of fungal populations, 34 rice blast isolates collected from various blast endemic areas of India were analyzed using Magnaporthe grisea genome specific microsatellite markers (MGM) and repeat element based Pot2 primer. All the blast isolates showed average pair wise similarities in the range of 0.15 to 0.9 and suggested the large variations with in the isolates collected from the different places. To know the genetic relationship among the blast isolates, a dendogram was generated based on analysis of MGM and Pot2 primers separately and in combination using SHAN/ UPGMA program. The cluster analysis grouped all the blast isolates in to different clusters mostly based on the location, from where they were collected. Based on International blast differential lines containing single resistance genes, it was identified that AVR Pi-k gene was present predominantly in isolate collected from Nellore in costal Andhra Pradesh; and AVR Pi-2 and AVR Pi-4 genes in isolates collected from Mandya (Karnataka). The isolates collected from Almora, Ranchi and Nawagam showed the presence of AVR Pi-1 and AVR Pi-4a genes. The present study helped us to understand the population diversity and their AVR genes spectra in the blast hotspot regions of India, which can be useful in deployment strategies for blast resistance genes in rice improvement programmes.Not Availabl

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Not AvailableThe experiment was conducted out at the Indian Institute of Rice Research, Rajendranagar, Hyderabad during dry season (Rabi) 2013-2014 and Wet season (Kharif) 2014 crop seasons. The objective was to establish the nature of relation between grain yield and yield components by partitioning the correlation co-efficients between grain yield and its components into direct and indirect effects by using simple correlation and path analysis. A correlation co-efficient and path analysis study was conducted with eleven parents and their 24 F1 crosses for eleven component characters including grain yield. The correlation studies of these crosses showed that, grain yield per plant exhibited highly significant positive association with plant height, number of productive tillers per plant, panicle length, grains per panicle, and harvest index while days to 50 per cent flowering registered non-significant negative association with grain yield.ICAR-Indian Institute of Rice Researc

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Not AvailableBroadening of the genetic base for identification and transfer of genes for resistance to insect pests and diseases from wild relatives of rice is an important strategy in resistance breeding programs across the world. An accession of Oryza nivara, International Rice Germplasm Collection (IRGC) accession number 105710, was identified to exhibit high level and broad-spectrum resistance to Xanthomonas oryzae pv. oryzae. In order to study the genetics of resistance and to tag and map the resistance gene or genes present in IRGC 105710, it was crossed with the bacterial blight (BB)-susceptible varieties 'TN1' and 'Samba Mahsuri' (SM) and then backcrossed to generate backcross mapping populations. Analysis of these populations and their progeny testing revealed that a single dominant gene controls resistance in IRGC 105710. The BC(1)F(2) population derived from the cross IRGC 105710/TN1//TN1 was screened with a set of 72 polymorphic simple-sequence repeat (SSR) markers distributed across the rice genome and the resistance gene was coarse mapped on chromosome 7 between the SSR markers RM5711 and RM6728 at a genetic distance of 17.0 and 19.3 centimorgans (cM), respectively. After analysis involving 49 SSR markers located between the genomic interval spanned by RM5711 and RM6728, and BC(2)F(2) population consisting of 2,011 individuals derived from the cross IRGC 105710/TN1//TN1, the gene was fine mapped between two SSR markers (RMWR7.1 and RMWR7.6) located at a genetic distance of 0.9 and 1.2 cM, respectively, from the gene and flanking it. The linkage distances were validated in a BC(1)F(2) mapping population derived from the cross IRGC 105710/SM//2 × SM. The BB resistance gene present in the O. nivara accession was identified to be novel based on its unique map location on chromosome 7 and wider spectrum of BB resistance; this gene has been named Xa33. The genomic region between the two closely flanking SSR markers was in silico analyzed for putatively expressed candidate genes. In total, eight genes were identified in the region and a putative gene encoding serinethreonine kinase appears to be a candidate for the Xa33 gene.Not Availabl

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Not AvailableThe experiment was conducted out at the Indian Institute of Rice Research, Rajendranagar, Hyderabad during dry season (Rabi) 2013-2014 andWet season (Kharif) 2014 crop seasons. The objective was to establish the nature of relation between grain yield and yield components by partitioning the correlation co-efficients between grain yield and its components into direct and indirect effects by using simple correlation and path analysis. A correlation co-efficient and path analysis study was conducted with eleven parents and their 24 F1 crosses for eleven component characters including grain yield. The correlation studies of these crosses showed that, grain yield per plant exhibited highly significant positive association with plant height, number of productive tillers per plant, panicle length, grains per panicle, and harvest index while days to 50 per cent flowering registered non-significant negative association with grain yield.Not Availabl

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Not AvailableBacterial blight (BB) disease reduces the yield of rice varieties and hybrids considerably in many tropical rice growing countries like India. The present study highlights the development of durable BB resistance into the background of an elite maintainer of rice, DRR17B, by incorporating two major dominant genes, Xa21 and Xa33 through marker-assisted backcross breeding (MABB). Through two sets of backcrosses, the two BB resistance genes were transferred separately to DRR17B. In this process, at each stage of backcrossing, foreground selection was carried out for the target resistance genes and for non-fertility restorer alleles concerning the major fertility restorer genes Rf3 and Rf4, using gene-specific PCR-based markers, while background selection was done using a set of 61 and 64 parental polymorphic SSR markers respectively. Backcross derived lines possessing either Xa21 or Xa33 along with maximum genome recovery of DRR17B were identified at BC3F1 generation and selfed to develop BC3F2s. Plants harboring Xa21 or Xa33 in homozygous condition were identified among BC3F2s and were intercrossed with each other to combine both the genes. The intercross F1 plants (ICF1) were selfed and the intercross F2(ICF2) plants possessing both Xa21 and Xa33 in homozygous condition were identified with the help of markers. They were then advanced further by selfing until ICF4 generation. Selected ICF4 lines were evaluated for their resistance against BB with eight virulent isolates and for key agro-morphological traits. Six promising two-gene pyramiding lines of DRR17B with high level of BB resistance and agro-morphological attributes similar or superior to DRR17B withcomplete maintenance ability have been identified. These lines with elevated level of durable resistance may be handy tool for BB resistance breedingNot Availabl

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Not AvailableBacterial blight (BB) and fungal blast diseases are the major biotic constraints that limit rice productivity. To sustain yield improvement in rice, it is necessary to developed yield potential of the rice varieties by incorporation of biotic stress resistance genes. Tellahamsa is a well-adapted popular high yielding rice variety in Telangana state, India. However, the variety is highly susceptible to BB and blast. In this study, simultaneous stepwise transfer of genes through marker-assisted backcross breeding (MABB) strategy was used to introgress two major BB (Xa21 and xa13) and two major blast resistance genes (Pi54 and Pi1) into Tellahamsa. In each generation (from F1 to ICF3) foreground selection was done using gene-specific markers viz., pTA248 (Xa21), xa13prom (xa13), Pi54MAS (Pi54) and RM224 (Pi1). Two independent BC2F1 lines of Tellahamsa/ISM (Cross-I) and Tellahamsa/NLR145 (Cross-II) possessing 92% and 94% recurrent parent genome (RPG) respectively were intercrossed to develop ICF1—ICF3 generations. These gene pyramided lines were evaluated for key agro-morphological traits, quality, and resistance against blast at three different hotspot locations as well as BB at two locations. Two ICF3 gene pyramided lines viz., TH-625-159 and TH-625-491 possessing four genes exhibited a high level of resistance to BB and blast. In the future, these improved Tellahamsa lines could be developed as mega varieties for different agro-climatic zones and also as potential donors for different pre-breeding rice research.Department of Biotechnology, Government of India grant # BT/ PR11705/AGR/02/646/200

Marker Assisted Gene Pyramiding (MAGP) for bacterial blight and blast resistance into mega rice variety "Tellahamsa".

Bacterial blight (BB) and fungal blast diseases are the major biotic constraints that limit rice productivity. To sustain yield improvement in rice, it is necessary to developed yield potential of the rice varieties by incorporation of biotic stress resistance genes. Tellahamsa is a well-adapted popular high yielding rice variety in Telangana state, India. However, the variety is highly susceptible to BB and blast. In this study, simultaneous stepwise transfer of genes through marker-assisted backcross breeding (MABB) strategy was used to introgress two major BB (Xa21 and xa13) and two major blast resistance genes (Pi54 and Pi1) into Tellahamsa. In each generation (from F1 to ICF3) foreground selection was done using gene-specific markers viz., pTA248 (Xa21), xa13prom (xa13), Pi54MAS (Pi54) and RM224 (Pi1). Two independent BC2F1 lines of Tellahamsa/ISM (Cross-I) and Tellahamsa/NLR145 (Cross-II) possessing 92% and 94% recurrent parent genome (RPG) respectively were intercrossed to develop ICF1-ICF3 generations. These gene pyramided lines were evaluated for key agro-morphological traits, quality, and resistance against blast at three different hotspot locations as well as BB at two locations. Two ICF3 gene pyramided lines viz., TH-625-159 and TH-625-491 possessing four genes exhibited a high level of resistance to BB and blast. In the future, these improved Tellahamsa lines could be developed as mega varieties for different agro-climatic zones and also as potential donors for different pre-breeding rice research

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Not AvailableTo create novel variants for morphological, physiological, and biotic stress tolerance traits, induced mutations were created using Ethyl Methane Sulphonate (EMS) in the background of Samba Mahsuri (BPT 5204), a popular and mega rice variety of India. A population derived from 10, 500 M1 plants and their descendants were phenotyped for a wide range of traits leading to the identification of 124 mutants having variations in key agro-morphological traits, and 106 mutants exhibiting variation for physiological traits. Higher yield is the ultimate goal of crop improvement and we identified 574 mutants having higher yield compared to wild type by having better yield attributing traits. Further, a total of 50 mutants showed better panicle exertion phenotypes as compared to Samba Mahsuri leading to enhancement of yield. Upon rigorous screening for three major biotic stresses, 8 mutants showed enhanced tolerance for yellow stem borer (YSB), and 13 different mutants each showed enhanced tolerance for sheath blight (ShB) and bacterial leaf blight (BLB), respectively. In addition, screening at multiple locations that have diverse field isolates identified 3, 3, and 5 lines for tolerance to ShB, YSB and BLB, respectively. On the whole, 1231 desired mutant lines identified at M2 were forwarded to an advanced generation (M5). PCR based allele mining indicated that the BLB tolerant mutants have a different allele than the reported alleles for well-known genes affecting bacterial blight resistance. Whole genome re-sequencing revealed substantial variation in comparison to Samba Mahsuri. The lines showing enhanced tolerance to important biotic stresses (YSB, ShB and BLB) as well as several economically important traits are unique genetic resources which can be utilized for the identification of novel genes/alleles for different traits. The lines which have better agronomic features can be used as pre-breeding lines. The entire mutant population is maintained as a national resource for genetic improvement of the rice crop.Not Availabl

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Not AvailableDRR Dhan 55 [IET 26194(RP 5591 - 123 - 16 - 2)], an aerobic rice variety developed from MTU1010/ IR79915 - B - 83 - 4 - 3 cross combination. It was evaluated in AICRIP multi - location aerobic rice trials during wet seasons of 2016 to 2019. DRR Dhan 55 consistently out - performed the check varieties in Eastern Zone (Zone III) and Central Zone (Zone V) with a mean grain yield 4974 kg/ha, which is 15%, 19% and 18 % higher than National check, Zonal and Local checks, respectively. In addition, it exhibited moderate resistance to Leaf blast and Neck blast; and also resistance to gall midge and rice thrips; and moderate resistance to plant hoppers. DRR Dhan 55 has medium duration of 120 - 130 days (seed to seed) and possess desirable grain andcooking quality parameters. It was released for cultivation in aerobic ecosystems of Bihar (Zone III) and Chhattisgarh (Zone V) states through Central Sub - committee on Crop Standards, Notification and Release of Varieties for Agricultural Crops vide S.O. 500(E) dt. 29th Jan 2021[CG - DL - E - 03022021 - 224901].Not Availabl