Introgression of Xa4, Xa7 and Xa21 for resistance to bacterial blight in thermosensitive genetic male sterile rice (Oryza sativa L.) for the development of two-line hybrids

• Published in: Euphytica 2008-12, Vol.164 (3), p.627-636
• Main Authors: Perez, Loida M, Redoña, Edilberto D, Mendioro, Merlyn S, Vera Cruz, Casiana M, Leung, Hei
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Bacteria; bacterial blight; bacterial diseases of plants; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Crop diseases; Crop production; disease resistance; Fertility; Fundamental and applied biological sciences. Psychology; genes; Genetic markers; Genetically altered foods; Genetically engineered microorganisms; Genetics and breeding of economic plants; Growth chambers; Heterosis. Floral biology applications: apomixy, male sterility, incompatibility, varia; Hybrids; Interspecific and intergeneric hybridization, introgressions; introgression; leaf blight; Life Sciences; marker-assisted selection; Oryza sativa; Phenotypes; plant breeding; Plant breeding: fundamental aspects and methodology; plant fertility; Plant Genetics and Genomics; Plant Pathology; Plant Physiology; Plant resistance; Plant Sciences; Pollen; Rice; Risk assessment; temperature-sensitive genetic male sterile lines; Transgenic plants; Tropical environments; Varietal selection. Specialized plant breeding, plant breeding aims; Xa21 gene; Xa4 gene; Xa7 gene; Xanthomonas oryzae pv. oryzae
• ISSN: 0014-2336; 1573-5060
• DOI: 10.1007/s10681-008-9653-1

Bacterial blight (BB) of rice caused by X. oryzae pv. oryzae is a major production constraint in commercial hybrid rice production in the Philippines because most of the parental lines used in hybrid production do not carry resistance genes against the pathogen. In this study, three bacterial blight resistance genes, Xa4, Xa7 and Xa21, were introgressed to a temperature-sensitive genetic male sterile (TGMS1) line. A three-way cross of AR32-19-3-3/TGMS1//IRBB4/7 (PR36944) was made to produce 1,364 F₂ plants carrying various combinations of Xa4, Xa7 and Xa21. Individual plants were characterized for reaction to bacterial blight PXO61 (race 1), PXO86 (race 2), PXO99 (race 6) and pollen sterility. Of 144 F₂ plants demonstrating resistance against PXO61, PXO86 and PXO99, 22 exhibited highly resistant phenotypes with mean lesion lengths ranging from 0.37-2.97 cm. Analysis of disease reaction identified 20 potential TGMS F₂ plants containing Xa4, Xa7 and Xa21 while 78 plants with Xa4 + Xa7. Phenotypic and polymerase chain reaction (PCR) analyses confirmed PR36944-450, PR36944-473 and PR36944-700 as homozygous for Xa7 and Xa21 and highly resistant to all three Xoo races. Fertility of PR36944-450 and PR36944-700 was restored at permissive temperature in a growth chamber. BB-resistant TGMS lines should facilitate breeding two-line hybrids in the tropics.