ARS | Publication request: RiceCAP: Identification of QTL Associated with Rice Milling Yield in a Long Grain Cross

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Proceedings/Symposium
Publication Acceptance Date: November 6, 2006
Publication Date: January 13, 2007
Citation: Fjellstrom, R.G., Linscombe, S.D., Oard, J.H., Moldenhauer, K.K., Boza, E., Jodari, F., Nelson, J., Yeater, K.M., Mcclung, A.M. 2007. RiceCAP: Identification of QTL Associated with Rice Milling Yield in a Long Grain Cross. Plant and Animal Genome XV, January 13-17, 2007, San Diego, CA. Available: http://intl-pag.org/15/abstracts.

Technical Abstract: Over the last 30 years of rice production in the US, field yields have increased by over 50% whereas milling quality has been improved by less than 5%. Milling yield is very difficult to select for in variety development programs because it is complexly inherited and is sensitive to environmental effects during grain development as well as post-harvest handling. The RiceCAP (Coordinated Agricultural Project) aims to discover the genetic bases for milling yield and sheath blight resistance in US rice germplasm. A mapping population was developed between Cypress (PI 561734), a long grain cultivar known for its high and stable milling quality, and RT0034, an indica derived long grain germplasm developed by RiceTec, Inc. Of the 430 polymorphic SSR markers identified between the parents, 155 were selected for genotyping the progeny. During 2005, 156 F12 progeny were grown and grain traits were evaluated using mixed-model composite interval analyses. The RILs showed about 2:1 segregation favoring the indica (RT0034) allele at most loci. This distortion in combination with the population size (reduced from the intended 300+ lines) is likely to have reduced the power of the analysis. However, some 40 QTL having LOD scores >7 were identified on ten of the chromosomes. The largest single QTL associated with whole milling yield was located on chromosome 9 and had a LOD score = 6.