Monday, November 5, 2007
81-4

Incorporation of DNA Markers to Develop Improved Southern Rice Breeding Lines.

Herry Utomo1, S.D. Linscombe2, and Xueyan Sha1. (1) Louisiana State University - Agronomy & Environmental Management, Rice Research Station LSU Agric. Center, 1373 Caffey Rd., Rayne, LA 70578, (2) Louisiana State University, 1373 Caffey Road, Rayne, LA 70578

DNA markers provide an excellent opportunity to conduct systematic selection for a number of important traits. A wealth of information upon completion of rice genome sequence has contributed to faster development of molecular markers aimed to tag various important traits in rice, including sheath blight resistance, milling quality, drought resistance, grain dimension and quality specifications, grain nutritional quality, and various yield components. Emerging potentially from various genetic backgrounds identified by scientists around the world, DNA markers for various traits currently of a local or ethnic preference can be used to introgress these traits into the U.S. rice background of already premium quality to meet specific demands in a wider market of more diversified consumers. A high level of precision in selecting the traits can be used to fast-tract such development and will make them a crucial part in developing high quality superior varieties. Even though the southern U.S. rice germplasm has a very narrow genetic background, new cultivars being released from this narrow gene pool have shown considerable yield improvement from time to time. Grain quality generally can be maintained rather easily by crossing parents of southern U.S. types. Significant total yield improvement, however, is relatively hard to achieve. Wide crossing such as using indica types to breed long-grain rice can improve yield substantially. However, it typically has poor grain quality and exhibits other undesirable traits not suitable for commercial production. Marker scoring representing known marker linked traits was conducted along with field selection among progeny rows. Gene pyramiding and introgression efforts using molecular markers to develop superior breeding lines will be discussed.