Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: December 1, 2001
Publication Date: June 1, 2002
Citation: BERGMAN, C.J., MCCLUNG, A.M., PINSON, S.R., FJELLSTROM, R.G. DEVELOPMENT OF PCR BASED MARKERS ASSOCIATED WITH COOKED RICE KERNEL ELONGATION AND AROMA. RICE TECHNICAL WORKING GROUP MEETING PROCEEDINGS. 2002. p. 53.
Cooked kernel elongation (CKE) and aroma are some of the end-use quality traits that differentiate highly valued specialty rices from conventional rices. Previous genetic studies have identified the recessive fgr gene on rice chromosome 8 that controls 2-acetyl-1-pyrroline (2-AP), the compound of greatest importance to aroma. Although this locus is linked with the RFLP marker RG28, RFLP markers are impractical for routine use in breeding programs. Published PCR markers associated with grain aroma are comprised of sequence-tagged-site (STS) primers based on the RG28 sequence or microsatellite markers near RG28. The RFLP marker RZ323 also maps to chromosome 8 and has previously been reported to explain 45 percent of genetic variance for CKE. Our objective was to map several PCR based markers that can be used in U.S. germplasm to provide breeders with markers that can be easily used to select for grain aroma and CKE. Populations from mcrosses between aromatic and non-aromatic rices were analyzed for segregation of 2-AP content, an RG28 STS marker, and 9 microsatellite markers linked to RG28. Results indicated that aroma was controlled by one gene and that the fgr locus is closely flanked between markers RG28 and RM223. A survey of markers in U.S. rice germplasm demonstrated that no unique marker alleles are found in aromatic germplasm and therefore markers must be chosen based on parental polymorphism and genetic distance from the fgr locus. Using one population that was also segregating for CKE, we found that the RM44 microsatellite located near RZ323, explained 74 percent of the genetic variance for CKE but was not closely linked to the fgr locus. These PCR based markers offer U.S. breeders new tools to select for specialty end-use quality traits.