Marker Aided Introgression of Blast Resistance Genes Pi1, Pi2 and Pi54 Into Intan Rice Variety
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Date
2016-12
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University of Agricultural Science, Dharwad
Abstract
Rice blast caused by Magnaporthe oryzae is the most devastating fungal disease that causes approximately 80 % yield loss. Use of resistant cultivars is the most effective and economical way to control rice blast disease. “Intan” is a medium slender indica variety, popular with farmers and consumers in Karnataka but highly susceptible to blast disease.
BPT5204 NIL-28, 18, 30 introgressed with Pi1, Pi2 and Pi54 which was developed in the Department of Biotechnology, UAS, Dharwad and Tetep, having Pi1 and Pi54 were used as donor parents in the crossing programme to develop F1’s, BC1F1’s and BC2F1’s. Marker assisted backcross breeding approach was adopted to introgress broad spectrum blast resistance genes Pi1, Pi2 and Pi54 independently and pyramided into Intan in 2015 & 2016.
Molecular markers genic/linked, flanking and unlinked to target genes were used as foreground, recombinant and background selection markers respectively. Genic marker RM224 for Pi1 gene, tightly linked marker AP5659-5 (0.10 cM) for Pi2 gene, RM206 (0.6 cM) for Pi54 gene showed polymorphism among the parents. These polymorphic markers were employed to confirm target genes in hybrids and backcross population. F1 plants generated from ‘Intan x Tetep’ cross was confirmed for the presence of Pi1 + Pi54 genes and confirmed plants were backcrossed. Further, these F1 plants were challenge inoculated with Magnaporthe oryzae isolates and F1’s showed resistant reaction, confirming the hybridity.
Foreground selection was exercised and heterozygous plants with Pi1, Pi54, Pi1 + Pi54 pyramids were identified in BC1F1 generation. Sixty three genome wide markers were subjected for polymorphism and polymorphic markers were employed for background selection. From ‘Intan x BPT5204 NIL-18’ cross, heterozygous plants for Pi2 gene were confirmed in BC2F1 generation and subjected for background selection, in which recurrent parent genome recovery ranged from 57.40 % to 81.48 %.