Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Identification Of QTLs For Tillering Ability In An Inter-Specific Rice Cross

L.S. Lim¹ , K.K. Sabu¹ , R. Wickneswari¹ , M.Z. Abdullah²

¹  School of Environmental and Natural Resource Sciences, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia.

²  Gene Bank, MARDI Seberang Perai, PO Box 203, 13200 Kepala Batas, Pulau Pinang, Malaysia.

Domestication and intensive breeding have resulted in a narrowing of the gene pool of modern rice cultivars. Wild and unadapted germplasm represents the majority of the existing genetic variation in rice. Common wild rice (Oryza rufipogon Griff.) has many useful genes which could improve the quality and yield potential of cultivated rice. We are focusing primarily on the tillering ability of O. rufipogon IRGC105491 to enhance the grain yield of MR219, an elite Malaysian rice cultivar. On average, O. rufipogon exhibits 70% more panicle-bearing tillers in comparison to MR219. The study involves the simultaneous transfer of tillering genes into an elite breeding line and the mapping of putative alleles with reference to the tillering trait via the advanced backcross approach. A significant 90% increase in the tillering of BC₂F₁ progenies compared to MR219, more than compensates for the expected 13% lower no. of filled grains per panicle observed. Moreover, a marked decrease in plant height by 24.7% and culm length by 31.6% would solve the problem of lodging exhibited by the MR219 cultivar. Generated BC₂F₂ will lay the groundwork for QTL analysis when tillering-related traits such as plant height, no. of tillers per plant, panicles per plant, spikelets per panicle and yield per plant will be correlated with genotypic data. We will identify chromosomal regions responsible for variation in tillering traits, characterize the relative importance of marker regions in terms of the proportion of phenotypic variation each controls and determine whether the same regions affect more than one trait.