Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: February 8, 2002
Publication Date: June 1, 2002
Citation: BERGMAN, C.J., MCCLUNG, A.M., PINSON, S.R., FJELLSTROM, R.G. DEVELOMENT OF PCR-BASED MARKERS ASSOCIATED WITH COOKED RICE KERNEL ELONGATION AND AROMA. RICE TECHNICAL WORKING GROUP MEETING PROCEEDINGS. 2002. p. 53. Technical Abstract: Aromatic rice is highly valued and growing in popularity throughout the world. Cooked kernel elongation and aroma are some of the end-use quality traits that differentiate these types of rice from those in conventional market classes. Our objective was to map several PCR based markers in order to provide rice improvement programs with markers that have respective strengths of linkage with grain aroma and cooked kernel elongation using germplasm relevant to the US. The aroma gene is known to be near RG28 or chromosome 8. Three genetic populations from crosses 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. The fgr locus was found closely flanked between markers RG28 and RM223. A survey of markers in US rice germplasm shows that aromatic and non-aromatic germplasm have many similar marker genotypes. Since no unique marker alleles are found in aromatic germplasm, markers for selection must be chosen in respect to parental polymorphism and genetic distance from the fgr locus. Using one of the same populations used in the aroma study that was also segregating for cooked kernel elongation, we found that the frequency distribution indicated that this trait is strongly influenced by the environment but controlled by one gene. A microsatellite, RM44, that maps near RZ323 explained 22 and 74 percent of the phenotypic and genetic variance, respectively, for cooked kernel elongation in this population. The RM44 marker appears to be 25.7 cM from the fgr locus. Thus, these two loci are not closely linked. These PCR based markers offer US breeders new tools to use for rapidly selecting end-use quality traits in their narrow-based elite germplasm.