Improvement of bacterial blight resistance in rice cultivars Jyothi and IR50 via marker-assisted backcross breeding

• Published in: Journal of crop improvement Vol. 21; no. 1; pp. 101 - 116
• Main Authors: Bharathkumar, S, Paulraj, R.S.D, Brindha, P.V, Kavitha, S, Gnanamanickam, S.S
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01-01-2008
• Subjects: artificial selection; backcrossing; Bacteria; bacterial blight; bacterial diseases of plants; blight; cultivars; Disease resistance; genetic resistance; IR50; Jyothi; marker-assisted selection; near-isogenic lines; Oryza sativa; pathotypes; plant breeding; plant pathogenic bacteria; RFLP; rice; STS markers; traditional backcrossing; Xanthomonas oryzae; Xanthomonas oryzae pv. oryzae; India
• DOI: 10.1300/J411v21n01_07
• EISSN: 1542-7536
• ISSN: 1542-7528

In pathogen population analysis of 208 Xanthomonas oryzae pv. oryzae(Xoo) strains that were assembled from different parts of India, 21 pathotypes were identified on the basis of disease reactions on near-isogenic lines (NILs) and 13 pathotypes, on rice differentials. Rice cultivars, Jyothi and IR50, which are high yielding but highly prone to bacterial blight (BB) caused by pathogen populations of Xanthomonas oryzae pv. oryzae in India, were chosen. To improve the BB resistance of these two varieties, a pyramid line, NH56, containing four R-genes, Xa4, xa5, xa13, and Xa21, was selected as the R-donor based on resistance to existing pathogen population. The four R-genes were successfully transferred to cultivars through a traditional backcross method and their presence was documented with marker-aided selection (MAS). Thirty BC
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plants derived from JxNH56 (cv. Jyothi) and 45 BC
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plants derived from IR50xNH56 (cv. IR50) had all four resistance genes (Xa4, xa5, xa13, and Xa21), which should be useful resistance donors for breeding other BB-resistant elite indica varieties.