Submitted to: US Japan Nutritional Research Panel
Publication Type: Abstract Only
Publication Acceptance Date: September 4, 2001
Publication Date: N/A
Technical Abstract: Using conventional breeding methods it can take a decade to develop a new rice cultivar. DNA markers offer a new tool for breeders to use to streamline the breeding process and reduce the development time for cultivars. We have developed genetic markers for key traits that are now being routinely used to select for amylose content, which largely controls rice cooking quality, and for resistance to the organism which causes rice blast disease. This paper reports progress in the development of markers that are associated with the fragrance gene in rice that produces 2-acetyl- 1-pyrroline and gives scented rices their popcorn flavor. Molecular markers were identified in two populations involving the aromatic parents, Dellmont and A-301, crossed with the non-aromatic genetic sources, B8462T3-710 and Labelle, respectively. Markers that were 3.6 cM and 1.9 cM away from the fragrance gene on chromosome 8 were found in the two populations, respectively, indicating that they are closely linked to the gene. Althoug the two aromatic parents were derived from the same aromatic source, Della, the two populations differed in which markers were polymorphic. We have also mapped markers in another region of chromosome 8 that are associated with cooked kernel elongation, a trait that is characteristic of basmati- type rices. Seven markers associated with high milling yield were identified after screening nearly 2000 AFLP and RAPD markers in a cross using the cultivar Cypress which is known for its superior milling quality. These markers will be verified in an independent genetic population using Cypress as a parent. All of the markers that we have developed so far are useful in narrow-based elite U.S. germplasm and will help breeders to more quickly develop cultivars for domestic and export markets.