Status of golden rice breeding in the Philippines
2008
Alfonso, A.A. | Dilla, C.J.A. | Ravelo, G.B. | Espejo, E.O., Philippine Rice Research Inst. Maligaya, Science City of Muñoz, Nueva Ecija (Philippines) Plant Breeding and Biotechnology Div | Aldemita, R.R., International Service for the Acquisition of Agri-Biotech Applications, IRRI Compound, College, Laguna (Philippines) | Avellanoza, E.S. | Garcia, N.S. | Sebastian, L.S., Philippine Rice Research Inst. Maligaya, Science City of Muñoz, Nueva Ecija (Philippines) Plant Breeding and Biotechnology Div
To help alleviate the persistent problem of vitamin A deficiency in the country, PhilRice has embarked on a research aimed at developing rice varieties biofertified with beta-carotene, a pro-vitamin A. A two-pronged strategy was initiated to transfer into local varieties with beta-carotene biosynthetic genes Phytoene Synthase and Phytoene desaturase from a transgenic donor (Golden Rice 1 event 309 in Cocodrie variety). One approach involved DNA marker-aided introgression of the GR309 into PSB Rc82 and NSIC Rc128. Foreground selection using an event-specific marker and background selection using 67 SSR markers are being conducted in developing GR versions of these varieties. A total of 253 BC2FI plants from the cross NSIC Rc128 x GR309 and 305 BC2FI plants from PSB Rc82 x GR309 were planted in 2007 WS. Foreground selection identified 73 and 128 BC2FI plants as GR+ in these crosses, respectively. In 2008 DS, five BC3FI populations of GR309 x Mabango 1 and 12 from GR309 x PSB Rc82 were planted. Out of the 804 plants, 409 were determined to be GR+. In each cross, at least 15 plants exhibited more than 90% recovery of the recurrent parents. These will be self-pollinated to produced uniform lines. The other strategy aims to develop new GR varieties with resistance to tungro and bacterial blight derived from non-transgenic donors. Resistant elite lines were crossed to GR309 and progenies were crossed to a line with excellent agronomic traits. Disease resistance was verified through pathogen inoculation. Another culture was initiated to fast-track the development of stable lines. Field testing of stable GR lines is planned for early 2009.
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