Plant Genome III Conference Plant Genome III Conference
Rice, Oryza saliva L., is an ideal species for genetic and biological studies for monocot plants. It is diploid (2n = 24) and has a small genome size (420 Mbp/1IC), which is < three fold larger than that of the model species for dicot plants, Arabidopsis thaliana, but > five fold smaller than maize and > 38 fold smaller than bread wheat. Furthermore, several high density molecular linkage maps, a classic genetic map, and a genetic transformation system have been developed, which will greatly facilitate genome research and genetic studies of rice. Additionally, rice is one of the most important crops and the staple for over half of the population in the world. Therefore, rice is not only an ideal species for genome research for monocot plants but also economically important. To facilitate genome research and map-based cloning of genes of agronomic importance in rice, we have constructed two bacterial artificial chromosome (BAC) libraries for rice from the parents of a permanent mapping population of 400 recombinant inbred lines developed at the Texas A&M University Agricultural Research and Extension Center, Beaumont, Texas. The parents, Teqing (0. saliva ssp. indica ) and Lemont (0. sativa ssp. japonica), represent the two major genomes of cultivated rice. The permanent mapping population developed from the cross between these varieties is segregating for many traits of agronomic importance, including disease resistance (blight and blast), heading date, plant type, and many component traits of yield. The Teqing BAC library consists of 14,000 clones with a range from 40 to 315 kbp in size and an average insert size of 130 kbp, which is equivalent to 4.3 genomes of rice. The Lemont BAC library consists of 10,000 clones with a range from 80 to 310 kbp in size and an average insert size of 150 kbp, which is equivalent to 3.5 genomes of rice. The probability to obtain a particular clone from either of these two BAC libraries is over 95%. Characterization of these two BAC libraries will be reported.