Detection of quantitative trait loci for cold tolerance at the booting stage in a rice breeding line, Hokkai-PL9

Abstract

We performed quantitative trait locus (QTL) analysis for cold tolerance at the booting stage (CT), heading date (HD) and culm length (CL) using 84 recombinant inbred lines derived from a cross combination between temperate japonicas Hokkai-PL9 (cold-tolerant) and Hokkai287 (cold-sensitive). CT was evaluated by fertility after cold water treatment. Three QTLs for CT were detected on chromosomes 1 (qCTB1.1 and qCTB1.2) and 8 (qCTB8.1), and Hokkai-PL9 allele at all three QTLs increased the level of CT. Phenotypic variance explained (PVE) of qCTB1.1, qCTB1.2 and qCTB8.1 were 18.8%, 11.8% and 14.2%, respectively. Three QTLs for HD were detected on chromosomes 2 and 3 (two QTLs), and nine QTLs for CL were detected on chromosomes 1, 2, 3 (three QTLs), 8, 9 (two QTLs) and 11. No QTLs for HD and CL were detected in the same region as QTLs for CT. The effects of the Hokkai-PL9 allele of QTLs for CT significantly increased CT, suggesting that QTL combination is effective for CT improvement.