Integrating marker assisted background analysis with foreground selection for identification of superior bacterial blight resistant recombinants in Basmati rice

Plant Breeding (Impact Factor: 1.34). 04/2008; 127:131—139. DOI: 10.1111/j.1439-0523.2007.01458.x

ABSTRACT Basmati rice is highly susceptible to bacterial blight (BB) caused by
Xanthomonas oryzae pv. oryzae. Transfer of BB resistance genes from
non-Basmati sources to Basmati through cross-hybridization requires
strict monitoring for recovery of the desirable Basmati quality traits in
the recombinants, which show complex inheritance pattern. We
integrated background analysis using mapped microsatellite markers
with foreground selection to identify superior lines that combine useful
genes from a non-Basmati BB resistance donor line IRBB55 with grain
and cooking quality characteristics of the popular Basmati rice variety
Pusa Basmati 1(PB 1) employing backcross pedigree strategy.
Foreground selection using linked markers ensured presence of two
genes, xa13 and Xa21 for BB resistance from IRBB55, and the
recurrent parent PB 1 allele for the waxy locus giving intermediate
amylose content and maintainer allele at fertility restorer locus in the
BC1F5 recombinants. Background analysis enabled selection of
recombinants with recurrent parent genome to the extent of 86.3%
along with the quality traits. The extent of introgression of non-
Basmati donor chromosome segments in the superior selections was
estimated to be <7.8 Mb and <6.7 Mb in the xa13 and Xa21 linked
genomic regions, respectively. Association mapping identified three
quantitative trait loci, one each for 1000-grain weight, fertile grains/
panicle and cooked kernel length. The backcross-pedigree breeding
strategy facilitated recovery of additional desirable characteristics from
the donor in some of the selections. The elite selection Pusa 1460-01-
32-6-7-67 with maximum genomic background and quality characteristics
of the recurrent Basmati parent gave resistance reaction against
BB, similar to that of the non-Basmati resistant check variety and
recorded an yield advantage of 11.9% over the best check in the
multiplication agronomic trial in the Basmati growing region of India.
This line, which has been released as a new variety in the name of
Improved Pusa Basmati 1 for commercial cultivation in India, is an
example of successful application of marker assisted selection to
variety development.


Available from: Anand Kullan, Feb 15, 2014
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    ABSTRACT: Globally, blast incited by Magnaporthe oryzae and sheath blight (ShB) by Rhizoctonia solani Kuhn forms two major fungal diseases that cause significant yield loss in rice. Pusa 6B, the Basmati quality maintainer line of the popular superfine grain aromatic rice hybrid Pusa RH10, is highly susceptible to both the diseases. The rice cultivar Tetep was used as the donor for transferring a major blast resistant gene, Pi54 and three ShB resistant quantitative trait loci (QTLs) namely, qSBR11-1, qSBR11-2 and qSBR7-1 into Pusa 6B using a marker assisted backcross breeding scheme with restricted number of backcrosses. Plants heterozygous for the alleles of interest and phenotypic similarity to the recurrent parent were used for generating BC1F2 population by selfing selected BC1F1 plants. Selected BC1F2 plants homozygous for Pi54 were selfed to generate BC1F3 families that were subjected to a step-wise reductive screening for the three ShB resistant QTLs. Final selections were advanced to BC1F5 generation through selfing while subjecting to stringent phenotypic selection. The advanced selections carrying blast and ShB resistant genes (Pi54, qSBR11-1, qSBR11-2, qSBR7-1) in the background of Pusa 6B were resistant to highly virulent strains of rice blast as well as ShB isolates without compromising the grain and cooking quality of Pusa 6B. Marker assisted transfer of blast and ShB resistance into Pusa 6B will aid in developing CMS lines with inbuilt resistance to these diseases. When combined with restorer lines possessing resistant genes/QTLs for these diseases, the improved Pusa6A lines will aid in development of improved Pusa RH10 and other novel aromatic hybrids with resistance to blast and ShB diseases. The present study demonstrates successful use of a restricted backcrossing strategy for introgression of multiple loci conferring resistance to two important fungal diseases in rice.
    Euphytica 10/2014; 203(1):97-107. DOI:10.1007/s10681-014-1267-1 · 1.69 Impact Factor
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    ABSTRACT: A set of NILs carrying major blast resistance genes in a Basmati rice variety has been developed. Also, the efficacy of pyramids over monogenic NILs against rice blast pathogen Magnaporthe oryzae has been demonstrated. Productivity and quality of Basmati rice is severely affected by rice blast disease. Major genes and QTLs conferring resistance to blast have been reported only in non-Basmati rice germplasm. Here, we report incorporation of seven blast resistance genes from the donor lines DHMASQ164-2a (Pi54, Pi1, Pita), IRBLz5-CA (Pi2), IRBLb-B (Pib), IRBL5-M (Pi5) and IRBL9-W (Pi9) into the genetic background of an elite Basmati rice variety Pusa Basmati 1 (PB1). A total of 36 near-isogenic lines (NILs) comprising of 14 monogenic, 16 two-gene pyramids and six three-gene pyramids were developed through marker-assisted backcross breeding (MABB). Foreground, recombinant and background selection was used to identify the plants with target gene(s), minimize the linkage drag and increase the recurrent parent genome (RPG) recovery (93.5-98.6 %), respectively, in the NILs. Comparative analysis performed using 50,051 SNPs and 500 SSR markers revealed that the SNPs provided better insight into the RPG recovery. Most of the monogenic NILs showed comparable performance in yield and quality, concomitantly, Pusa1637-18-7-6-20 (Pi9), was significantly superior in yield and stable across four different environments as compared to recurrent parent (RP) PB1. Further, among the pyramids, Pusa1930-12-6 (Pi2+Pi5) showed significantly higher yield and Pusa1633-7-8-53-6-8 (Pi54+Pi1+Pita) was superior in cooking quality as compared to RP PB1. The NILs carrying gene Pi9 were found to be the most effective against the concoction of virulent races predominant in the hotspot locations for blast disease. Conversely, when analyzed under artificial inoculation, three-gene pyramids expressed enhanced resistance as compared to the two-gene and monogenic NILs.
    Theoretical and Applied Genetics 04/2015; DOI:10.1007/s00122-015-2502-4 · 3.51 Impact Factor
  • ENCYCLOPEDIA OF SUSTAINABILITY SCIENCE AND TECHNOLOGY, Edited by Robert A. Meyers, 01/2013: chapter Modeling Frameworks for Determination of Carrying Capacity for Aquaculture: pages 417-448; Springer New York., ISBN: 978-1-4614-5796-1