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Title: PROGRESS TOWARD POSITIONAL CLONING OF SEED DORMANCY QTLS FROM WEEDY RICE (ORYZA SATIVA)

Author
item Foley, Michael
item XINGYOU, GU - NDSU
item KIANIAN, SHAHRYAR - NDSU

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/9/2004
Publication Date: 5/25/2004
Citation: Foley, M.E., Xingyou, G., Kianian, S.F. 2004. Progress toward positional cloning of seed dormancy QTLs from weedy rice (Oryza sativa) [Abstract]. 3rd International Symposium on Plant Dormancy. p. 28.

Interpretive Summary: A wild-like weedy strain SS18-2 was selected to investigate the genetic architecture underlying seed dormancy. A framework genetic map covering the whole rice genome was constructed based on 156 BC1 [EM93-1(non-dormant breeding line)//EM93-1/SS18-2] individuals. The mapping population was replicated using a splitting-tiller technique to control and better estimate the environmental variation. Dormancy was determined by germination of seeds after 1, 11, and 21 days of after-ripening (DAR). Six dormancy QTLs, designated as qSDS-4, -6, -7-1, -7-2, -8, and -12, were identified. The locus qSDS-7-1 was tightly linked to the red pericarp color gene Rc. A QTL×DAR interaction was detected for qSDS-12, the locus with the largest main effect at 1, 11, and 21 DAR (R2 = 0.14, 0.24, and 0.20, respectively). Two and higher (three and four) orders of epistases were detected with 4 and all of the 6 QTL, respectively. The higher-order epistases strongly suggests the presence of genetically complex networks in the regulation of variation for seed dormancy in natural populations, and makes it critical to select for a favorable combination of alleles at multiple loci in positional cloning of a target dormancy gene. The weedy rice derived dormancy alleles are being introduced into the EM93-1 genetic background to develop near isogenic lines.

Technical Abstract: A wild-like weedy strain SS18-2 was selected to investigate the genetic architecture underlying seed dormancy. A framework genetic map covering the whole rice genome was constructed based on 156 BC1 [EM93-1(non-dormant breeding line)//EM93-1/SS18-2] individuals. The mapping population was replicated using a splitting-tiller technique to control and better estimate the environmental variation. Dormancy was determined by germination of seeds after 1, 11, and 21 days of after-ripening (DAR). Six dormancy QTLs, designated as qSDS-4, -6, -7-1, -7-2, -8, and -12, were identified. The locus qSDS-7-1 was tightly linked to the red pericarp color gene Rc. A QTL×DAR interaction was detected for qSDS-12, the locus with the largest main effect at 1, 11, and 21 DAR (R2 = 0.14, 0.24, and 0.20, respectively). Two and higher (three and four) orders of epistases were detected with 4 and all of the 6 QTL, respectively. The higher-order epistases strongly suggests the presence of genetically complex networks in the regulation of variation for seed dormancy in natural populations, and makes it critical to select for a favorable combination of alleles at multiple loci in positional cloning of a target dormancy gene. The weedy rice derived dormancy alleles are being introduced into the EM93-1 genetic background to develop near isogenic lines.