QTL mapping and development of candidate gene-derived DNA markers associated with seedling cold tolerance in rice (Oryza sativa L.).
Cold stress at the seedling stage is a major threat to rice production. Cold tolerance is controlled by complex genetic factors. We used an F7 recombinant inbred line (RIL) population of 123 individuals derived from a cross of the cold-tolerant japonica cultivar Jinbu and the cold-susceptible indica cultivar BR29 for QTL mapping. Phenotypic evaluation of the parents and RILs in an 18/8 °C (day/night) cold stress regime revealed continuous variation for cold tolerance. Six QTLs including two on chromosome 1 and one each on chromosomes 2, 4, 10, and 11 for seedling cold tolerance were identified with phenotypic variation (R(2)) ranging from 6.1 to 16.5 %. The QTL combinations (qSCT1 and qSCT11) were detected in all stable cold-tolerant RIL groups, which explained the critical threshold of 27.1 % for the R(2) value determining cold tolerance at the seedling stage. Two QTLs (qSCT1 and qSCT11) on chromosomes 1 and 11, respectively, were fine mapped. The markers In1-c3, derived from the open reading frame (ORF) LOC_Os01g69910 encoding calmodulin-binding transcription activator (CAMTA), and In11-d1, derived from ORF LOC_Os11g37720 (Duf6 gene), co-segregated with seedling cold tolerance. The result may provide useful information on seedling cold tolerance mechanism and provide DNA markers for a marker-assisted breeding program to improve seedling cold tolerance in indica rice varieties.
Plant Breeding, Genetics, and Biotechnology Division, International Rice Research Institute, 7777, Metro Manila, Philippines, s.kim@irri.org.
Suk-Man
SM
Kim
Jung-Pil
JP
Suh
Chung-Koon
CK
Lee
Jeong-Heui
JH
Lee
Yeong-Gyu
YG
Kim
Kshirod Kumar
KK
Jena
D000220:Adaptation, Biological / Q000235:genetics*; D002874:Chromosome Mapping; D003080:Cold Temperature; D017343:Genes, Plant; D008040:Genetic Linkage; D005819:Genetic Markers; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000254:growth & development*; D010641:Phenotype; D040641:Quantitative Trait Loci; D015203:Reproducibility of Results; D036226:Seedlings / Q000235:genetics*; D013312:Stress, Physiological
D005819:Genetic Markers